i

Climate Compatible Wetland-Based Sanitation for Sustainable Cities (Eco-Cities) in East Africa

By

Thomas Lugeiyamu Balthazar

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in

Urban Water Engineering and Management at the Asian Institute of Technology and

the degree of Master of Science in Municipal Water and Infrastructure at the UNESCO - IHE

Examination Committee: Dr. Oleg Shipin (Chairperson) Prof. Chettiyappan Visvanathan Dr. Sangam Shrestha Dr. Assela Pathirana - (UNESCO – IHE)

Nationality: Tanzanian Previous Degree: Bachelor of Engineering in Civil Engineering Dar es Salaam Institute of Technology Tanzania

Scholarship Donor: Bill & Melinda Gates Foundation/UNESCO – IHE/AIT

Fellowship

Asian Institute of Technology School of Engineering and Technology–School of Environment, Resources and Development

Thailand May, 2014

ii

ACKNOWLEDGEMENTS

I would like to express my sincere gratitude to my advisor Dr. Oleg Shipin for his continuous motivation, valuable advices and kind support throughout the whole period of the research. His continuous guidance has been the major factor behind the timely completion of my thesis. I sincerely appreciate his efforts on building my professional capacity in addition to the thesis work.

This research was completed with support of many people within Asian Institute of Technology and UNESCO-IHE. I highly appreciate their support that they have provided to me during the research writing period.

I would like also to express my gratitude to Bill and Melinda Gates Foundation (BMGF) for providing financial support to complete my Master’s Degree in Urban Water Engineering and Management double degree program.

I am very grateful to thank members of committee Prof. C. Visvanathan, Dr. Sangam Shrestha and Dr. Assela Pathirana for their valuable guidance and which suggestions and comments that contributed immensely to refine my thesis work.

I highly appreciate the support provided by Dr. Kimwaga and Mr. L. Gastory of the Department of water resources engineering at the College of Engineering and Technology (CoET) of the University of Dar es Salaam Tanzania and the Hacienda Holdings Corporation manager Mr. P. Muthai in Mombasa Kenya during research study and data collection.

I dedicated this research work to my parents who gave me the strength and courage to face the challenges of life and I appreciate their moral support and guidance to make me a successful professional in Urban Water Management.

Finally I wish to express my love and appreciation to my wife “Beatrice, my daughter Bevelyne and my son Bryan” who have set their humiliation and provided me with peaceful space and time encouragement in completion of my research timely while bearing all my social responsibility. I always remember and love them.

iii

ABSTRACT

This research was done to propose a Climate Compatible process design of a Wetland-Based Sanitation for sustainable Cities in East Africa cities namely in Dar es Salaam and Mombasa. Through completion of this study the inventory assessment of existing sanitation situation in the studied areas were done through related stakeholders. The assessment discovered that 80% of the surveyed WSPs & CWs experience various forms of operational problems. The major problems experienced was a combination of blockages and over loading (43%) whereas blockage itself constituted 26%. Other operational problems are seepages through the walls or leakage and cracks which altogether constituted 11%. The study also find that 78% of population in the surveyed areas they do not have access to piped sewerage, due to insufficient funding allocated to sewerage and wastewater treatment investments which is appearing disproportionate when compared to the high percentage of growing population.

The performance efficiency removal of several wastewater parameters from Hacienda eco-city estate development wetland-based sanitation system were conducted to see if the final effluents discharged are achieving climate compatible development. The study revealed successful performance of the existing tropical CW for the secondary treatment of domestic wastewater with respect to organic matter (BOD, NO3-N and NH3-N) with removal efficiency of 95, 78, and 86% respectively. For these parameters the quality of effluent meet the admissible local standard for discharging in surface water courses with 29.7, 9.04 & 12.96 mg/l respectively. The performance assessment of the existing wetland-based sanitation system for wastewater management in Hacienda in Mombasa were considered only secondary data. It has been concluded that the wetland system is compatible to climate change.

Furthermore, a review to evaluating retrofit feasibility for development of sustainable wetland-based sanitation in the studied cities were conducted where by a design proposal for the climate change compatible system were developed by considering the existing septic tanks in the case study areas with unplanned settlement and should be connected into secondary septic tank and then to the secondary wetland treatment and finally polished in tertiary wetland for final discharge. The system aim is to promote the paradigm shift towards low emission and climate resilient development pathway by supporting the region to limit the greenhouse gas (GHG) emissions and adapt to the impacts of climate change through wastewater management.

Finally the author recommended that for the proposed waste management system to live up to its expectations requires a coordinated supervision by all relevant stakeholders, Governments and its departments responsible for wastes and environmental management, as well as local communities. Strong public participation in this infrastructure management at local level is emphasized for effective operation of the system. Therefore additional institutional capacity for wastewater related operations need to be restructured and initiated in the East Africa region’s local administrative structures.

Keywords: Climate change compatibility, wetland-based sanitation, sustainable cities, reduction of GHGs emissions, floods and droughts mitigation.

iv

TABLE OF CONTENTS

CHAPTER TITLE PAGES TITLE PAGE i ACKNOLEDGEMENT ii ABSTRACT iii TABLE OF CONTENTS iv LIST OF FIGURES vii LIST OF TABLES viii LIST OF ABBREVIATIONS ix

1 INTRODUCTION 1

1.1 General Background 1

1.1.1 East Africa 1

1.1.2 Sustainable city (Eco-City) 2 1.1.3 Wetland-based sanitation 2

1.2 Problem statement 3 1.3 Research objectives 4

1.3.1 Overall objective 4 1.3.2 Specific objectives 4 1.3.3 Research questions 4

1.4 Scope of the study 5

2 LITERATURE REVIEW 6

2.1 Sustainable city (Eco-city) 6 2.1.1 Origins and driving factors for Eco-City concept 8 2.1.2 The concept of Eco-city 9 2.1.3 Eco-Cities and the environment 10 2.1.4 Urban sustainability 10 2.1.5 Farming in the ecological cities 11 2.1.6 Eco-City criteria 11

2.2 Wetland-based sanitation system 12 2.2.1 Waste Stabilization Ponds (WSPs) 12 2.2.2 Constructed Wetlands (CWs) 15

2.3 Climate Change Compatible Development 20 3

RESEARCH METHODOLOGY

24

3.1 Introduction 24 3.2 Study areas 24 3.3 Study location 24 3.4 Sanitation coverage 25

3.4.1 National level 25 3.4.2 Overview of Dar es Salaam Sanitation 26

3.5 Research Design 27 3.6 Research Methods 28

3.6.1 Sampling 28

v

3.6.2 Data Collection Techniques 28 3.6.3 Household Surveys 30 3.6.4 Participatory Urban Appraisal (PUA) 30 3.6.5 Key Informants and Institutional interviews 30 3.6.6 Direct Field Observation 30 3.6.7 Literature Review 30 3.6.8 Data Processing and Analysis 31

3.7 Second case study area in Mombasa 31 3.7.1 Residential solid and liquid waste sampling 32 3.7.2 Conduction of Interviews 32 3.7.3 Standard Questionnaires 33 3.7.4 Field Observations 33 3.7.5 Secondary sources of data 33 3.7.6 Limitations of this study 33

3.8 Hacienda Eco-City in Mombasa 34 3.8.1 Study site and sampling 34 3.8.2 Statistical and Laboratory Analysis 35

4 RESULTS AND DISCUSSION 37

4.1 Inventory assessment of existing wetland-based sanitation in Dar es Salaam and Mombasa city through related stakeholders was conducted as follows;

37

4.1.1 Current Sanitation in Dar es Salaam city (Tanzania) 37 4.1.2 Existing sanitation in Mombasa city (Kenya)

37

4.2 Performance of the existing wetland-based sanitation in Mambasa, namely, the large scale housing estate, ‘Hasienda Eco-City’ was evaluated and results were drawn as follows:

59

4.2.1 Performance Efficiency of CW on Treating Domestic Wastewater

59

4.3 Eco-city related developments in Mombasa were reviewed and evaluated with regard to retrofit feasibility for development of sustainable wetland-based sanitation in Dar es Salaam as follows:

66

4.3.1 Introduction 66 4.3.2 Purpose of the Design 66 4.3.3 Design Objectives: 66 4.3.4 Domestic Wastewater and Effluent Quality 67 4.3.5 Design Components 67 4.3.6 Design Criteria 69 4.3.7 Horizontal Flow Constructed Wetland (HSSFCW) Components 75 4.3.8 Constructed Wetland system processess 75 4.3.9 Operation and Maintenance 75 4.3.10 Construction costing

77

5 CONCLUSIONS AND RECOMMENDATIONS 78

5.1. Conclusions 78 5.2 Recommendations 80

vi

REFERENCES 81 APPENDICES 89 Appendix A: Tables for performance efficiency removal of HSSFCW 89 Appendix B: Tables for existing HSSFCWs in East Africa 94 Appendix C: Summary of performance efficiency results of CW units 95 Appendix D: Questionnaires used in research study 96

vii

LIST OF FIGURES

FIGURE: TITLE:

1.1 Map of East Africa map region 1 2.1 CITYBLUES++ concept 7 2.2 FWS with floating macrophytes 16 2.3 FWS with emergent macrophytes 16 2.4 Operation of Horizontal Sub-surface Flow (HSSF) CWs 17 2.5 Operation of Vertical Sub-surface Flow (VSSF) CWs 18 2.6 Biodiversity in Construction Wetlands (CWs) 19 2.7 Climate Compatible Development; 22 3.1 Location of two cities in East Africa where case study was conducted 24 3.2 Map of Dar es Salaam city 25 3.3 Sanitation Status and coverage in Tanzania 25 3.4 Sanitation coverage in Dar es Salaam 26 3.5 Overall conceptual research plan 27 3.6 The conceptual framework for data collection 29 3.7 Map and location of Mombasa city 31 3.8 Map of Mombasa in the coast province showing Hacienda eco-city 34 4.1 Model of sanitation used in Dar es Salaam as per interviewed respondents 38 4.2 Sewerage coverage in Dar es Salaam as per interviewed respondents 38 4.3 Solid waste disposals and mismanagement system 39 4.4 Traditional pit latrines in the study area 40 4.5 Water table at Hananasif Street 40 4.6 Sanitation facilities in the study area. 41 4.7 The facilities used to store solid waste in the cases study area 41 4.8 Contaminants in a natural drainage system discharging s/water 42 4.9 Percentage of respondents on the use of bathing facilities in Dsm 42 4.10 Percentage of respondents on useful facilities for anal cleansing 43 4.11 Emptying services in Dar es Salaam city 43 4.12 Tankers discharging septic tanks wastewater/sludge at Vingunguti WSPs 45 4.13 Existing construction wetland sites in Dar es Salaam city 50 4.14 Over-flooding of CW at Azam Stadium in Dar es Salaam 51 4.15 Mombasa Island sewerage catchment and location of treatment plant sites. 54 4.16 Sanitation facilities and Sewerage coverage in Mombasa Kenya 58 4.17 Temperature & pH variations in influents and effluents in the studied CWs. 59 4.18 BOD5 levels (mg/L) in influents and effluents in the studied CWs 60 4.19 NO3-N levels (mg/L) in influents and effluents in the studied CWs 62 4.20 PO4 levels (mg/L) in influents and effluents in the studied CWs 63 4.21 NH3-N levels (mg/L) in influents and effluents in the studied CWs 64 4.22 Design Components flow diagram 67 4.23 Two compartment septic tank cross-section 70 4.24 HF subsurface constructed wetland cross-section 74 4.25 Plates (a) to (f) are wetland components; source: CW manual Tanzania 75

viii

LIST OF TABLES

FIGURES: TITLE: 2.1 Sustainable environment aspects which are applicable to the eco-city concept 9 2.2 Performance efficiency of Horizontal subsurface flow CW 17 3.1 Study area population and size of Municipalities in Dar es Salaam 26 3.2 Households sample size carried out in Dar es Salaam 28 3.3 Participatory respondents of the ward residents 30 3.4 The stakeholders targeted to be evolved in interviews 32 4.1 Network coverage for the existing sewers under DAWASCO 46 4.2 Status of the existing pump stations 47 4.3 Performances of some of existing waste stabilization ponds (WSPs) in Dsm 49 4.4 Summary of Existing Trunk Sewers of sewered areas of West Mainland 56 4.5 Average loading rates for domestic septic tanks and average effluent quality 67 4.6 Management plan for Septic tanks and Constructed Wetland 75 4.7 Proposed costing for Implementation of CW and its components 77

ix

LIST OF ABBREVIATIONS

AIT Asian Institute of Technology

DEWATS Decentralized Wastewater Treatment System ABPP African Biogas Partnership Programme BORDA Bremen Overseas Research and Development Association UNEP United Nations Environmental Programme CCD Climate Compatible Development DCC Dar es Salaam City Council CDM Clean Development Mechanism WSUD Water Sensitive Urban Design UNCED United Nations Conference on Environment and Development UNFCCC United Nations Framework Conversion on Climate Change GHG Green House Gas CH4 Methane CO2 Carbon dioxide N2O Nitrous Oxide UNDP United Nations Development Programme IPCC International Panel on Climate Change NEMC National Environmental Management Council UDSM University of Dar es Salaam CoET College of Engineering and Technology IRA Institute for Research Assessment CCCS Center for Climate Change Studies COP Conferences of Parties HRT Hydraulic Retention Time FS Faecal Sludge WSP Waste Stabilization Ponds CWs Construction Wetlands CBD Convention on Biological Diversity NAPA National Adaptation Programme of Action NAMA National Appropriate Mitigation Actions CMA Census Metropolitan Area IWMA International Water Management Institute BOD Biochemical Oxygen Demand HSSF Horizontal SubSurface Flow FWS Free Water Surface DO Dissolved Oxygen HBS Household Based Survey LMS Living Measurement Standard SPSS Statistical Package for Social Sciences

1

CHAPTER ONE

INTRODUCTION

1.1 General Background

1.1.1 East Africa

East Africa is the region in which geographically, located in the eastern part of Africa continent. Politically, is the region that comprising of five countries which are Tanzania, Uganda, Kenya, Burundi and Rwanda. Among residents of this region the Eastern Africa usually refers ten countries, the countries within East Africa plus Sudan, Ethiopia, Djibouti, Somalia and Eritrea.

Domestic and Municipal wastewater treatments are taken as the major and important stimulate for East Africa economic growth. Furthermore, they are also the major course of climate change because they are normally resulting on non-urbanization for water resources and land utilization where rapid degradation are taking place. Due to increase of energy demands the region become into interest of looking for the renewable energy that will replace current use of fossil fuel energy. Several non-organization companies have been increasing the initiatives on securing the sources of energy in the region. Those international NGOs are the African Biogas Partnership Programme (ABPP) which is jointly partnership between Hivos and Netherlands Development Organization (SNV) and Bremen Overseas Research and Development Association (BORDA), presently they are increasing efforts securing energy East Africa.

Figure 1.1: Map of East Africa showing its five countries, source: https://www.google

2

1.1.2 Sustainable city (Eco-City)

Sustainable city or (Eco-City) is the capacity to endure. Sometimes we can define sustainable cities as “the human settlement that enables its residents to live a quality life while using minimal natural resources” In ecological systems it expresses how biological systems remain intact and productive over time. For human sustainable development for long-term maintenance of well-being, which has ecological, economic and cultural aspects.

An eco-cities aims to build a viable future for humanity with a healthy planet that need to depend on renewable technology to support people’s lives to preserve ecosystems. Currently, our natural resources have been disturbed that lead in destabilizing the planet’s life-support systems. Three key issues leading to our problems are: (a) the increase of global urbanization and growth of population which is estimated to grow to 9 billion by 2050; (b) the resource consumption rapid growth related with urbanization, particularly in emerging economies; and (c) presence of climate change. 2008 is the year which was demarcated time in history that half of the population lived in urban centers. It is expected that the world population by 2050, will grow up twice as much as 3.3 billion in 2007 (U.N., 2008). This is to analyze the present global changes and to realize if and how we can be able acquire for the sustainable development. It’s time to agree that the cities climate compatibility and adaptation of wetland-based sanitation technology can lead the way to safeguard the environment.

The environmental management statistics shows us that a total of 15,589 species of plants and animals are in danger of being extinct, 50% of wetlands have disappeared, sea levels have risen by 20 cm, due to the temperature increase, all being caused by human activities (UNEP, 2010). Human activities also cause issues such as global dimming that prevent the sun’s energy and rays from reaching the Earth’s surface. This has been caused by rise in the aerospace particles in the atmosphere (Denman et al., 2007). However the all costs and risks of climate change will be equivalent to losing up to 20% worldwide GDP each year, while the adaptation costs now can be reduced to around 1% of global GDP each year (International Union for Conservation of Nature 2012).

According to Brundtland Report, (1987) dealt with sustainable development and explains the change in the political system. The highlight of this report was trying to define the sustainable development which is known today as “development that meet their own needs of the present without compromising the ability of future generations to meet their own needs”. The report aims to conceptualize the needs for world’s poorest economies and the limitations of technology and organization on the sustainability of the environment (U.N., 1987).

1.1.3 Wetland-based sanitation

Wetland-based sanitation is a new technology which is presents needed to be established for the aim of treatments of wastewater. Globally, there are several thousand wetland systems which have been deployed to treat wastewater from different sources of pollution which is either from point source or non-point source pollution. The WBS technology is now need to be addressed through several stakeholders concerns with environmental control and wastewater management this is due to the economically advantages which contributes to be the best option. The technology does not need any machinery, chemicals, anthropogenic energy input and become new chosen system in operation and maintenance requirements.

3

Principally, WBS systems are designed in order to be coupled with existing septic tanks at a place where there is no access of the piped sewerage network (unplanned settlements) so that to help treatment of wastewater which are normally discharged untreated in the environments. The system comprises of septic tanks and constructed wetland and it involving planting of vegetation, bed substrates (gravels), utilize also the use of natural processes to carry out process of wastewater treatment.

In other words, CWs attempt to replicate the function of natural wetlands and other aquatic systems but in more controlled manner (U S EPA, 2004) thereby involving the physical, chemical, biological processes. The most stable micro biota in these systems is found in the biofilm formed inside the system: on root plants or filter bed material surface. The complex microbial community associated with the filter material or roots, created by interactions with the wastewater, is main contributor to degrading efficiency of the system (Sleytret et al., 2009).

Research has continuously revealed increasing levels of pollution in receiving water points for decades. Important pollution components discharged in receiving water include excess nutrient levels, microbiological and chemical pollutants, suspended solids, which result from direct human activities, untreated municipal sewage, agricultural waste brought in by inflowing rivers, maritime transport, and runoff and storm water inflow (Katima et al., 2005).

These components have led to reduction in diversity of fish species, reduced levels of oxygen, increased salt loading, and emergence of water hyacinth, all of which eventually impact on the increased incidence of diseases and general health of the people (Karanja, 2006). This pollution acceleration within the water resource will have a tremendous impact on human welfare in the region. Technological solutions, specifically incorporation of WBS technology in the sanitation service, will have long term positive impacts towards improving sanitary status and biodiversity. Yet, most actors and stakeholders in the provision of sanitation services are unaware of the efficacy of this technology, hence minimal uptake. It also evaluates and proposes technological coupling with CW towards achieving complete wastewater treatment cycles and meeting recommended effluent discharge standards.

1.2 Problem statement

Sustainable city or (Eco-City) is becoming increasingly popular in a wide variety of countries across the world. The Eco-city concept presently addresses its aspects dealing with low cost urban Wastewater treatment-Energy-Food nexus for climate change adapted urban development. It aims to demonstrate that a rapid growing developing city can turn what is otherwise viewed as institution-specific problems into a unified resource-based path to prosperity, adapted to climate changes challenges, and achievable with current successful best practice implementation of wetland-based sanitation technologies. However, the rapid growing of urbanization and treatment of wastewater technologies in East Africa is considered as an enforcement of economic growth, currently being lacking of proper technology of treating our wastewater lead to serious problems which are greatly association with environmental depletion, specifically based on releasing of greenhouse gas emissions to the atmosphere and discharge of untreated or partially treated wastewater to the natural water courses, and eventually resulted into climate change (Kyambadde 2005) & (Environmental Protection Authority (EPA) 2003).

4

It was reported that less than 60% of people in East Africa have no enough access to water and sanitation service (WSP, 2002).

It was estimated that about 75 – 250 million people in Africa by the 2020 could have to face the challenges of shortage of clean water, food and health risk in which all of these are exacerbated by the climate change impacts (ECA, 2008). In addition, the tendency of releasing greenhouse gases (GHGs) unsafely into the atmosphere through process of anaerobic bio-conversion of wastes to biogas which contain 50% of methane that mimic the hazards of climate change. It was revealed that one unit of methane contributes 21 computed for a 100-year horizon or 56 computed for 20 years in the global warming (Ayalon et al. 2001) & (IPCC. 2007). The existing few conversion wastewater treatment plants in East Africa are either focusing on reducing pollution load alone or biogas production but neither designed integrated wastewater treatment systems, biogas, wastewater re-use, nutrients recovery, energy supply nor mitigation of climate change.

1.3 Research objectives

1.3.1 Overall objective

The objective of this research study is to propose a Climate Compatible process design of a Wetland-Based Sanitation for sustainable Cities (Eco-city) in East Africa (as exemplified by cities of Dar es Salaam, (Tanzania) and Mombasa, (Kenya).

1.3.2 Specific objectives

1. To conduct inventory assessment of existing sanitation in Dar es Salaam and Mombasa city through related stakeholders with a focus on climate compatible wetland-based sanitation.

2. Evaluate the performance of wetland-based sanitation in the Hacienda eco-city (housing estate) in Mombasa while focusing on achieving climate compatible development.

3. To review eco-city-related developments in Mombasa with a view to evaluating retrofit feasibility for development of sustainable wetland-based sanitation in Dar es Salaam.

1.3.3 Research questions

1. How much biogas can be produced if the resulting faecal sludge and plant biomass is used as fermentation substrate?

2. How wetland-based sanitation can become a source of income generation through resource recovery and energy production while achieving climate compatible developments.

3. What is citywide potential for clean development mechanism (CDM) if the proposed approach is implemented?

4. What policies are in place and what practices are applied in the eco-city for implementation of climate change compatible initiatives so that to reduce GHG emissions?

5

1.4 Scope of the study

The scope of this research study will be based in Dar es Salaam city Tanzania and at Hacienda eco-city in Mombasa Kenya which is current best successful implementation Eco-city development and addressing the Climate Compatibility in East Africa by;

1. Assessing and analyzing climate compatible development for achieving sustainability through wetland based sanitation technology.

2. Investigating the performance of existing construction wetlands so as to mitigate the impacts of climate change.

3. Identifying how wetland based sanitation system of wastewater treatment is operated while reducing the emissions of greenhouse gases (GHG).

4. Due to lack of manpower, study budget and instruments the study was mainly conducted by interviews according to the prepared questionnaires. Some of bio-technological parameters such as water qualities was gathered only based from the recent literatures and references.

6

CHAPTER TWO

LITERATURE REVIEW

2.1 Sustainable city (Eco-city)

Sustainable cities (Eco-City) is now becoming increasingly popular in a wide variety of countries across the world. The city itself has been questioned in terms of sustainability over the past decades on the basis of ongoing population growth and associated challenges of natural resource depletion and environmental pollution (Rapoport et al., 2011). “Green” technologies and practices are costly, and especially difficult to implement in developing countries. The intended purpose of implementing an Eco-city is generate the principles of recycling wastes so that to reduce carbon emission which contributes into greenhouse gases (GHG). All wastes in the eco-city are recycled in order to produce renewable and other nutrients while keeping or promoting eco-friendly environments. However, sustainable cities also intended to strengthen the economic growth, reducing poverty, organizing cities to focusing in eco-infrastructure developments and therefore to promote higher efficiency and improving hygiene.

“Eco-city" is a design method of human urban and economic environmental performance practiced around the world. With rapid growth of the world’s urban population and increasing concerns about environmental impacts (climate change, natural resource depletion etc.), the need for making urban living more sustainable is increasingly addressed by academics, architects and government officials. Sustainability concerns three basic components of a city - environmental, social and economic features. An Eco-City is an urban area that is ecologically sound and where the wastes resources are always deducted from impacting the environment. The re-use of these wastes is becoming into popularity where recycling have been used for reproducing renewable energy and nutrient resources such production of fertilizers for growing different agricultural plants within the eco-city boundaries. Depending on the efficiency and benefit per geographical location, the Eco-City concept need to be initiated so that to promote and implementation of sustainable development in the region.

Basically an Eco-City is focusing on principle of minimizing the use of land, energy and engage in promoting self-contained local economy while reducing carbon through a mix of renewable energy that can be supplies and mitigation of climate change, encouraging recycling practices and implementing of natural green spaces in the city area. They focus on sustainability through a minimal ecological footprint that can be achieved by perusing various clean technologies and practices of daily life applications e.g. implementing green transportation system for the public, by minimizing cars from using fossil fuels, maximizing the efficiency of reusing energy through wastes recycling for resource conservation, water and nutrient resources, and establishing a solid waste management system which insists the reuse and re-cycling of solid materials. By greening public and private spaces through the enhancement of urban ecosystems and waste land recovered, where environmentally degraded in the urban areas are restored.

Green architecture need to be promoted since it can provides best and affordable building for all groups being in ethical or socio-economically, this will improve job opportunities resulting in poverty alleviation and benefiting disadvantaged groups such as (women, minorities, disabled persons etc.).

7

More detailed aspects of a sustainable city are given in Figure 2.1 below. Examples of applying such sustainable urban practices include the so called “CITYBLUES++” project, conducted since 2011 in Vientiane, Laos, the system has been established to provide a link in the issues pertaining to environmental management so that to put a strategy for achieving sustainability, while involving public participatory processes and local government (CITYBLUES++, 2012).

The innovative approach of this particular project is based on establishing interdisciplinary connections of the aforementioned urban functions, by eventually turning urban sewage into a value added product, greening urban areas and mitigating GHG emissions, which meets the sustainable aspects of a “Eco-City” initiative.

CITYBLUES++ brings to green energy (the first +) in the form of biogas production from domestic/municipal wastewater and industrial organic material, septic tank slurry and aquatic-plants biomass as well as strengthening food-security (the security) in the form of biogas by-product sludge as soil conditioner along with Resource-Based Sanitation.

Figure 2.1 CITYBLUES++ concept

8

2.1.1 Origins and driving factors for eco-city concept

Ecological design and planning is not new in the literature, already (Wolman, 1965) started, that the cities should be accounted for its major physical inflows and outflows which most importantly should be integrated into the rest of the biospheric nature. The Eco-City concept recommends an eco-system alternative to urban development, management could change life of living within the city.

At the same time socio-economic considerations and ecological requirements are applied that favour the minimization of energy inputs, food and water, and output of waste, heat, air pollution that enhance safe and attractive environment to live and work. According to report by (Register, 1987), he proposes the eco-city to be built like a living system, where environment of the whole city is supported by land use patterns, hence biodiversity is enhanced, where building spaces are obtained vertically instead of spreading out and thereby building an incentive not using a car and relying on renewable energy. From this background, Eco-cities would have characteristically a compact and pedestrian-oriented layout with mixed-use urban areas which have a priority for re-using land and relying on public transport.

Afterwards several similar concepts arose, such as “urban eco-village”, “eco-neighbourhoods” and “eco-communities” which all have their priority on sustainability and environment-friendly practices.

Even (Mc Harg, 1969) had already developed ecological planning concepts for a land use methodology which includes the integration of natural and human environments. The idea of his work “Design with Nature” was fast known through Europe and especially adopted in the Netherlands. Nature imitating components such as stones, logs, wild rose and wetland layouts were landscaped in Delft and Utrecht and the concept of improving human well-being by harmoniously fitting natural aspects into their habitat of dyke, polder and reclaimed lands were adopted. Almost simultaneously after World War II, the formerly human basic needs oriented production practices shifted towards large industrial capitalism that now made consumerism highly accessible to developed countries based on technological progress. Today consumerism represents a collective consumption lifestyle which has spread to affluent social parts of the developing countries as well and what turned out to be ecologically disastrous in many cases. Sustainable production and consumption is a way of balancing the negative effects of consumerism and individual needs, therefore consumption should be matched with production which is lead and regulated by a demand management that sustainably evaluates natural resources availability and promotes recycling, reduction and reuse of materials.

At the same time applying technologies which are less polluting, protecting the environment and handle residues in an environmentally friendly way while production methods consume less resources. Sustainable consumption need to promote a conserver choice of lifestyle in the future, while maintaining a high quality of life. In the perspective of more developed countries (Newman et al., 2008) acquired a set of strategies concerning sustainable consumption so that to achieve the intended development goals.

9

2.1.2 The concept of Eco-city

To arrive at a definition for Eco-Cities, one must peruse a much broader concept of the Eco-city rather than focusing on single examples of a specific implementations. This is due to the increasing range of existing cities which “renovate” themselves as an Eco-city and the complete new urban projects which are designed as “Eco-cities” from the very beginning on as well. This broader concept for example incorporates three substantial analytical categories: 1) the Eco-city must be a development of substantial scale, 2) occurring across multiple sectors, 3) which is supported by policy processes (Rapoport et al., 2011).

The following set of criteria has been brought up by (Jones et al., 2010) concerning sustainable aspects of build environments which are intrinsically connected to the eco-city concept.

According to (Wong et al., 2011) the Eco-city planning puts its emphasis on the environmental aspects while sustainable planning equally takes social, economic and environmental aspects into account. The Eco-city planning and management is based on the principles of minimizing the use of land, energy and materials while taking a cyclical urban metabolism into account and an emphasis of the natural environment which eventually will lead to lower or to zero carbon settlement. According to the Eco-definition is strongly dependent on the focus of scale and quantification methods should be developed to comparatively scale and compare the Eco-definition of different places and projects.

The European Green City Award can be given as an example of attempting the quantification at the city level, where a list of eco-city parameters is divided into 13 fields and are applied as criteria (Jones et al., 2010).

Table 2.1: Sustainable build environment aspects which are applicable to the eco-city concept (Jones et al., 2010) CITYBLUES++ objectives are red outlined.

10

2.1.3 Eco-Cities and the environment

Several current cities performs quite different compared to existing one which have been built in a long time ago (inherited cities) and the management of environment issues are treated differently due to the increase of human activities that result into risks.

Current growing urbanization settlements are affected with many unplanned settlements which result to people’s life un-civilisation and mobilization of resources, people and products are not well organised.

Urban ecological footprint analysis assumes that every category of energy and material consumption and waste discharge requires the productive or absorptive capacity of a finite area of land or water (Wackernagel et al., 1996). The sum of all land and water required to meet material consumption and waste discharge of defined population is that populations’ ecological footprint on the earth. This does not have to coincide with the populations’ home region. Ecological footprint analysis reveals the growing competing demands on natural capital and it also raises the issues both equity and the long-term of production sustainability. By establishing the ecological footprint of different life styles, infrastructure, consumption patterns and certain densities separately, it is possible to develop strategies to reduce environmental impacts and the depletion of natural resources.

Local agenda 21 cities are required to list activities to reduce ecological footprint, while at the same time increasing the quality of life for inhabitants (UN-Habitat, 2003).

2.1.4 Urban sustainability

Urban sustainability is an increasing globally agenda that brought the international community to start addressing its importance. The Earth Summit held in Rio de Janeiro Brazil were the first international meeting to address the urban sustainability developments through the agenda 21. The second UN City summit were conducted in 1996 in Istanbul, through this summit 100 pages of agenda 21 were released to the 180 nations/states. The agenda emphases that, “Human settlements shall be planned, developed and improved in a manner that takes full account of sustainability development principles and all their components, as set out in Agenda 21”. There is a need to change our behaviour to respect and protect the eco-systems from being depleted and preserve the opportunities for the future generations

It is recognised that current cities use too much natural resources & generate more waste. The cities ecological are degrading out the habitat of many species. The city’s impacts extends far beyond its normal boundaries and coverage. However many cities are affected with a high increasing of population growth and, therefore, an increasing number users of the urban products. urban agricultural therefore has an important role in contributing to the future sustainability of cities (Carr et al., 2004).

11

2.1.5 Farming in the ecological cities

This section is concentrating on the major environmental constraints associated with urban agriculture and its potential role to help improve the ecological performance of cities (Reijntjes et al., 1992). One of the major factor during carrying out zoning and designing the urban farming aspects must be considered. The space for farming must be preserved for the purpose of growing of food.

Millennium Development Goals (MDG) which was established by the UN-Habitat Agenda of the City Summit in Istanbul outlines various practical approaches to developing sustainable human settlements, and the more recent also underscore the need to urgently improve the lives of millions of people staying in unplanned urban settlement in which they have no any access to safe drinking water and sanitation. East African cities are struggling in achieving sustainable development through managing cities, improving infrastructure development and environmental restoration. This will ensure the accessibility of modern amenities for the largest number of people in the city (Nwaka, 1992). The rapid population growth in mega and medium growing cities provide many economies to serve the people’s life with safe environmental infrastructure services.

Furthermore, the provision of rural agricultural economy and helping to meet the material needs of the people which is a major concern for sustainable development. The major challenge facing the region is how to exploit these potential opportunities within the cities, while reducing the negative environmental impacts and health threats they pose (Hosier, 1992).

2.1.6 Eco-City criteria

According to (Kennedy et al., 2011), they emphases that current there are specific principle to take into consideration so that to achieve the initiatives for what is called an “eco-city”, three keys principles have been recommended to satisfy an eco-cities, these are economic, social and environmental qualities. The following bellow are principles or criteria set to enhance eco-city;

• Initiatives for zero carbon emissions and generation resources

• Green transport required i.e. walking and recycling

• Encouraging the recycling of wastes and reuse to achieve sustainable development.

• Restore environment damaged urban areas

• Support local agriculture and produce

According to Shen et al., (2011). The governments should provide habitants with a good quality of life in their cities. This is particularly important when taking into consideration infrastructure designs, such as for water system, power lines, etc. In the world many cities have developed plans for sustainable urban development for leading their urbanization programmes towards a desired urban sustainability.

12

2.2 Wetland-based sanitation system

Wetland-based sanitation are natural proven efficient technological system which presently its use are increasing globally adopted for the wastewater and storm water treatment. Compared to Activated sludge technology, WBS system does not require higher investment funds since it is very cheap in terms of construction cost, also it is easily to operated and maintained and have a strong potential for application in developing countries (Kivaisi et al., 2001). These systems are consisting of shallow (usually 1.1m deep) ponds, channels and canals, which may be either planted or unplanted of aquatic plants and they are rely microbial, biological and chemical processes, natural die-off of pathogens, filtering, radiation of sunlight etc. to treat the wastewater in a controlled manner (Reed et al., 1995).

Wetland-based sanitation systems can be classify into two groups which are Waster stabilization ponds (WSPs) and Constructed wetlands (CWs) all of these systems are natural technologies that have been chosen as an effective solution for treatment of wastewater and storm water, its investment is very cheap in terms of construction. However this research is basically looking on how effective of this treatment technology on treating sewage produced in the septic tanks and pit latrines in the area where there is existence of sewers.

Wetland-based sanitation systems is the technology which is to established by linking the existing septic tanks water to secondary septic tank hence to the construction wetland purposely to treat wastewater to required effluent discharge standards (Mitsch et al., 2000). WBSs are very capable to meet the demand for high percentage removal of pathogens organisms, compared to activated sludge technology.

WSPs and CWs coupled and joined with other technologies, can result into better performance of wastewater systems (Kivaisi et al., 2001). In tropical climates like East Africa WSPs and CWs are presently established methods for wastewater treatment they have advantages including; simplicity, cheap cost, easy maintenance, low energy consumption, robustness and sustainability (Kayombo et al., 2005).

2.2.1 Waste Stabilization Ponds (WSPs)

According to (Mara, 1987), Waste Stabilization Ponds (WSPs) are large and shallow basins enclosed embankments in which raw wastewater is biologically treated by natural processes which involving bacteria and algae in the pond. WSPs components comprises a single series of anaerobic, facultative and maturation ponds or several of such series in parallel arrangements.

A long hydraulic retention time is necessary because of the slow rate at which the organic waste oxidized. WSPs hydraulic retention times usually range between 10 days to 100days depending on the existing surface temperature in a particular area.

In warm climate WSPs are considered as the most effective and appropriate technology for wastewater treatment where sufficient land is available and where temperature is most favourable for their operation (Mara, 1976). WSPs are not only restricted to countries with warm climates; they have also been used in other regions with cold climates in the USA and Europe (Abis, 2002). US Environmental Protection Agency (EPA, 1983) reports that about 7000 pond systems in USA have been constructed for treatment of wastewater from domestic and industrial.

13

WSPs can be found into three major types which are Anaerobic, facultative and maturation ponds. These ponds are normally arranged in series to achieve treatment purpose of raw wastewater (Marais, 1974). Anaerobic and facultative ponds are employed for removal of Biochemical Oxygen Demand (BOD). While maturation ponds are deployed for excreted pathogens removal, although some BOD also can be removed in maturation ponds and some pathogens removal in anaerobic facultative ponds (Mara, 1987).

Types of Waste Stabilization Ponds (WSPs) systems

The WSPs systems consists of three types as described above, these are.

• Anaerobic ponds

Anaerobic ponds are usually deep of about (2 – 5 m) high with appropriate inlet and outlet piping. Anaerobic ponds are used for treatment of high strength organic loads of wastewater (usually greater than 0.1 to 0.4 kg BOD/m3.day, equivalent to more than 3000 kg/hr. day for a depth of 3 m) that also contain a high concentration of solids (Mara et al., 1986). These pond are functioning well for BOD removal.

The following summarize the design criteria for the facultative pond;

Depth (d) = 2 – 5 m

Maximum organic load allowable = 0.1 to 0.4 kg BOD/m3.day

Retention time range between 2 – 5 days.

Rate of sludge accumulation is 0.04 m3/capital.day

L s = 10LiQ/A

L e = Li/[6(L i/Le)4.8 * (t+1)]

Where;

A is the surface area in m2

Ls is the organic load, kg BOD/ha.day

Le is the effluent BOD, ppm

Li is the influent BOD, ppm

• Facultative ponds

Facultative ponds are the lagoons having an anaerobic zone near surface with gradient to anaerobic condition near the bottom.

The oxygen sources are from the action of the photosynthesis by the algae and from the wind action, but oxygen provided cannot maintain total aerobic condition in the deeper facultative pond. They are usually 1-2 m deep and are geometrically to have a length ratio (up to 10:1) to simulate a hydraulic plug flow regime (Mara et al., 1992).

These pond have two types; primary facultative and secondary facultative pond. The primary facultative ponds are ones that receives raw wastewater from anaerobic pond and the secondary ponds are the ponds which receives settled wastewater effluent from the primary pond. Both anaerobic and aerobic conditions are found in the facultative pond (Mara et al., 1998).

14

The following summarize the design criteria for the facultative pond;

Depth (d) = 1.0 – 2 m

Maximum organic load allowable = 20T-60, kg BOD/ha.day

Retention time range between 10 – 15 days.

A = Q/(dK1) * [(L i/L e) – 1]

Where;

A is the surface area

d is the depth of the pond

K1 is constant depends on average winter temperature, = 0.235 for t = 15ºC

• Maturation ponds

Maturation ponds are the ponds used for the reduction of pathogens organisms. Normally they are used in series with facultative ponds. They are commonly 1 – 1.5 m deep and geometrically designed to have a high length-to-width ratio (up to 10:1) to simulate hydraulic plug flow regime (Mara et al., 1992).

The primary function of maturation pond is to remove excreted pathogens to enable the practice of unrestricted crop irrigation (WHO, 1989). The removal of BOD and nutrients has been observed to take place in maturation ponds.

Besides removing a very high percentage of faecal bacteria, viruses, protozoa, and other pathogens, maturation pond may also remove some algae and some nutrients. The bacterial effect of the maturation pond is due to several natural action as, solar ultra-violet radiation, high temperature, high pH value, as well as natural die-off (Kayombo et al., 2005).

The treated effluents from these ponds shall be discharged by gravity towards water stream, or can also be used in the future for reuse in irrigation projects or gardens and recreational purposes.

The following summarize the design criteria for the maturation pond;

Depth (d) = 1.5 m

Retention time up to 5 days.

Ne = Ni/ [(K tR1 +1) * (K tR2 + 1) * (KtR3 + 1)]

Where;

Ni is the influent Coliform number per 100 ml.

Ne is the effluent Coliform number per 100 ml.

Kt is coefficient = 2.6(1.19)t-20, t is the minimum winter temperature

R is the retention in time in anaerobic, facultative and maturation ponds.

15

2.2.2 Constructed Wetlands (CWs)

Constructed Wetlands (CWs) is rectangular structure with inlets and outlets designed to carry out wastewater treatments through utilizing of natural processes involving the use of wetland aquatic plants, bed substrates in which microbial bacteria can decompose waste materials to facilitate the treatment of wastewater.

More findings res-tresses that CWs as a designed, man-made structures comprises of substrates of different sizes, vegetated plants (emergent or submerged). Constructed wetlands (CWs) are now a well-established technology for wastewater treatment. Globally, there are many CW systems dealing with treating wastewaters from different sources, such as the point source and non-point source pollution (Katima et al., 2005).

Currently in East Africa, CWs attempt to replicate the function of natural wetlands and other aquatic systems but in more controlled manner (EPA, 2004) thereby involving the physical, chemical, biological processes. The most stable micro biota in these systems is found in the biofilm formed inside the system: on root plants or filter bed material surface. The complex microbial community associated with the filter material or roots, created by interactions with the wastewater (Sleytret et al., 2009).

Application of Constructed Wetlands (CWs) technology in East Africa

Over more than twenty 15 years, 20 Constructed Wetland units have been designed, constructed and established in East Africa by the University of Dar es Salaam Waste Stabilization Ponds and Constructed Wetland Research Group in collaboration with several stakeholders. (Katima et al.,2005). Fifteen CWs units have been established in Tanzania, two units in Uganda and each in Kenya, Ethiopia and Seychelles (Table 2.3) in Appendix B. Some of CWs units were developed for research purposes and others they are established to treat wastewater in East Africa region.

CWs systems were designed to carry out secondary and tertiary treatments while considering the removal several organic and inorganic pollutants and nutrients such as BOD, TSS, NO3-N, NH3-N etc. to the required effluent discharge standards for East African countries local bodies and adhering to the World Health Organisation (WHO) standards.

Types of Construction Wetlands (CWs)

Different types of CWs for wastewater treatment can effectively treat secondary wastewater, and tertiary sewage. Wetland systems is designed and constructed to be used as the secondary treatment wastewater, does not treat raw sewage this is to protect the system from clogging. Wastes may need to undergo primary treatment either in septic tanks or in facultative ponds so that to allow biological elements found in the wetlands to perform effectively with the effluent (Kivaisi et al., 2001).

The application of CWs systems become the practical alternatives to conventional treatment of wastewaters of different natures such as domestic, industrial etc. (Kleinmann et al., 1987).

16

Free Water Surface CWs

Surface flow constructed wetlands are mostly resembled with natural wetlands. The system need large area to be employed than subsurface flow systems for the same wastewater treatment these systems are not a recommended in East Africa since it located in tropical climate, they can attract insects to breed into the system because of water column being contact with atmosphere.

Among other disadvantages, surface flow wetlands pose a great risk of exposure to pathogenic organisms and other problems like presence of nuisance and odour. Surface flow wetlands can play a great role for attraction value of wildlife habitat which make them to live within.

FWS constructed wetlands are made up of ponds, channels or canals with shallow depth. Water flows through the system at a relative density. The FWS wetlands are commonly dense areas or open water areas with vegetation (Mbuligwe et al., 2011) If emergent macrophytes or rooted submerged macrophates are used, a suitable substrate is needed to support the vegetation (Kivaisi et al., 2001). Soluble organic compounds are removed through microbial communities which are attached to the vegetation.

The degradation can proceed both aerobic and anaerobic (Kadlec et al., 1996). Plant uptake is mainly responsiple for removal of nutrient. However, nitrogen can also be controlled through ammonia volatilization and nitrification. Oxygen is provided by the nitrifires grow attached to the roots. Diffusion of oxygen become limited if the densely water is covered with macrophytes in the wetland which lead to decrease of level of DO. Therefore anaerobic condition will occur (Kivaisi et al., 2001).

Figure 2.2: FWS CWs with floating macrophyte, source; CWs manual Tanzania

Figure 2.3: FWS CWs with emergent macrophytes, source; CWs manual Tanzania

Horizontal Subsurface Flow CWs

Horizontal subsurface flow CWs are natural system in which its performance allows water to flow horizontally to the system surface throughout the substrate. Gravel media or substrates provides a supportive surface area for growth of microbial bacteria (Katima et al., 2005).

17

The advantages of HSSF CW's performs better in removing pollutants and controlling nuisance and pest problems, its water column does not contact direct with atmosphere, it requires less land to be deployed compared to surface flow systems (Kadlec et al., 1996). The removal efficiency listed below are based on literature data and calculated from domestic and municipal wastewater concentrations (Mairi et al., 2013).

Table 2.2 Performance efficiency of HSSFCW

Characteristic Removal Efficiency %

Biochemical Oxygen Demand (BOD) 80

Chemical Oxygen Demand (COD) 65

Suspended Solids (SS) 70

Total Nitrogen (TN) 40

Total Phosphorus (TP) 40

Figure 2.4: Operation of Horizontal Subsurface Flow (HSSF) CWs, source; CW manual 2008

Vertical Subsurface Flow CWs

Vertical Subsurface flow CWs are the system which allows wastewater to flows vertically from top to bottom or from bottom to top of the system through the media. The gravel media or substrates provides a surface area for growth of microbial bacteria. Vertical subsurface flow constructed wetlands allows gradually percolation of wastewater through the substrate and is collected by drainage pipes at the bottom (Kivaisi et al., 2001). The system has an excellent nitrifying capacity through better oxygen transfer (Kayombo et al., 2005).

The VSF system is normally useful for treating secondary effluent from septic tanks or and other pollutants. Septic tanks removes suspended solids that if allowed to enter, it can impend or clog the wetland system.

18

Figure 2.5: Operation of Vertical Subsurface Flow (VSSF) CWs, source; CW manual 2008

There are two types of SSF systems, according to Brix, (1987a,b); and Cooper et al., (1996) oxygen is supplied in the system through the roots of emergent plants and is used up in the Biofilm growing directly on the roots and rhizomes. It was revealed that SSF systems are good for nitrate removal of denitrification, even if it cannot perform efficiently for ammonia removal (nitrification), this is because of presence of oxygen which limit the step during the nitrification processes (Baker, 1998).

Blockages of inlets and outlets structures are very common problems facing the workability of Subsurface flow systems, this can lead to malnufunctining of the system from working properly in treating wastewater (Kayombo et al., 2005).

The main objective of using CWs technology for wastewater treatment is to remove all organic matter and other contaminants before discharge to the environments. Also to control or mitigate all possible greenhouse gases emissions from being released to the atmosphere which can result into climate change impacts. It has been recognized that natural systems great advantages over conventional activated sludge and other systems (Kayombo et al., 2005). The CWs systems offers more natural environments through chemical and physical processes the system resulting in minimal operation and maintenance (Katima et al., 2005).

Wetland functions

Wetlands perform a number of critical functions agricultural benefits, fisheries, energy supply, emissions of GHG reduction and mitigation of droughts.

Flooding

Wetlands can be performed as flood control structures for harvesting all surface runoff water from rainfall and acts as a storage basin which eventually in the future water can be used to mitigate droughts problems. Other way around wetlands plants help slowly down of flooding. Slowly flow of water allows more time for its percolate through the soil rather than continue downstream by the conditions improvement in the soil. Constructed wetland can receive runoff surface water and act as storage detention pond which later uses to mitigate droughts problems by recycling in the households use or for irrigation.

19

Recreation Landscape and enhancement

Landscape ecology is encouraging for minimum or targeted design using the maximum forces of nature. It is a system based on natural regeneration and the self-renewal capacities of organic design. Urban landscape ecology should use plants which are locally and/or regionally adapted. Moreover, the design should include aesthetic considerations and should include achievable at lower development cost and maintenance requirements.

Nature conservation fish and wildlife habitat

Many animals, plants and birds depend on wetlands for their survival. Most fish breed and raise their young in coastal marshes, wetlands and estuaries. Further, shrimp, oysters, clams, and Dungeness crabs likewise need these wetlands for food, shelter, and breeding grounds. Some animals and birds, like wood ducks, they actually create their own life in wetlands. Wetlands provide important food, water, or shelter of the dependent living organism. Some animals and birds they migrate from inland to coastal land where there are availability of wetland as resting, feeding, breeding, or nesting grounds for certain seasons of the year.

Figure 2.6: Biodiversity in CW, source IR2 report, 2013

20

2.3 Climate Compatible Development

Climate compatible Development (CCD) is “a new development phenomena which deals with encouragement of the development to minimize the harm caused by climate change impacts, while maximizing the many human development opportunities by promoting low emissions of carbon, and more resilient for the future generation”. The better responses to climate change can lead into changing patterns of innovation, more production, trading, population distribution and able to attain risks (Parry et al., 2007). The climate compatibility is creating a new development landscape for the countries responses to climate change through policy makers, those needs to promote their economic growth and social development in the face of multiple threats and uncertainties while also reducing emissions or keeping them low (Haines et al., 2010). In fighting with the challenges, climate compatible development works beyond the traditional while tackling the problems together by adaptation, mitigation and development strategies on climate impacts (IPCC, 2007). “Triple win” has been set to as the strategies encouraged climate compatible development to deal with low emissions, build resilience and promote development growth which requires policy makers to consider when planning. East Africa region it has been evidenced in excessive floods and droughts which lead to millions of people become in starvation, cause health hazards through waterborne diseases hence deaths and contributing to ecosystem collapse while increasing energy demand due effects of climate change (Parry et al., 2007). Although greenhouse emissions from East Africa are small compared to other regions, it makes economic sense for the region to pursue a climate compatible part from today onwards (FAO, 2010b). Climate-compatible growth has two elements;

• Low-carbon growth, which aims to minimize the level of greenhouse gas emissions from economic growth and

• CCD focuses also in resilient growth, through reducing the risks from climate change – such as floods, droughts and sea level rise by ensuring the resilience of key economic assets to any consequences of climate change is prevented.

Fankhauser et al., (2010), emphases as Climate-compatible growth is currently being considered as a new development paradigm by many East African countries to secure a sustainable future for the millions on the region.

The use of wetland-based sanitation technology for wastewater treatment it has an important link with climate change impacts generated from wastewater treatment. Through excessive impacts it is required to achieve climate compatible development by reusing treated wastewater, renewable energy production, nutrients recycle, fish breeding, recreation and promoting the use natural resources (IPCC, 2007c).

21

2.3.1 Potential for sanitation in Climate change mitigation and Adaptation

Greenhouse effect and responsible gases

Many human activities cause emissions of GHGs emissions which drives the climate change impacts to the earth’s surface. The climate change report by Intergovernmental Panel emphasis that, the atmospheric greenhouse effect will cause a rise in the mean global temperature of between 1.1 and 6.4ºC by the end of 21st century (IPCC, 2007a), a change in rainfall patterns, a rising sea level and weakening of sea currents which will have an additional impact on the global temperature distribution. In order to limit climate change to tolerable levels, global temperature rise has to be limited to 2ºC (IPCC, 2007b). To achieve this, GHG emissions would have to be reduced by 50% by 2050 compared to the level in 1990 (IPCC, 2007c).

The Kyoto Protocol brought an important achievement at the Rio Summit in which agreement were set on the Climate Change Convention. This Summit were initiated by the UNFCCC with specific goals on reduction of Global warming which was incepted in December 1997 and were implemented in February 2005. This agreement were signed and agreed upon the formality by the 191 member of states under USA (United Nations, 2012). The statistics supporting environment protection and management on greenhouse gases (GHG) outlined in the Kyoto Protocol were as follows. Between times and 1994, Carbon Dioxide (CO2) increased in concentration by 30%, Methane (CH4) has more than doubled in concentration, Nitrous oxide (N2O) has increased in concentration by 15% and halocarbons have all increased.

GHGs Development strategies

Climate compatible development signifies a new development step; a step which characterized by changing the way and opt on seeking the development on fighting with harms that have been caused by climate change impacts while maximizing the development opportunities. This is a major stage for policy makers globally, who must navigate these changes while promoting and sustaining low emissions resilient growth and social development (Nicholls et al., 2007).

Strategies are needed to build a long-term commitment and relationship between nationals and put together the agreed goals and policies to enable the elimination of risks and uncertainties that are consistent with international agreements and politically accountable (Hedger et al., 2010; Kaur 2010).

22

Figure 2.7; Climate Compatible Development; source adapted from Zadek, 2009.

GHGs Mitigation Strategies

Since World War II urbanization is increasingly accelerating and by today more than half the world’s population lives in cities. Accordingly cities became major sources of greenhouse gas (GHG) emissions and became also them self-vulnerable to climate change (Klein et al., 2007). Especially in India, China and Latin America, the urban growth of developing countries affects lives of hundreds of millions of people and is fundamentally changing it. Particularly in urban accumulations where people and assets are concentrated, the impacts of climate change occur in the form of loss from flooding’s and hurricanes, the increase in global temperatures and rising of sea levels. With increasing concerns about environmental security, cities will raise attempts to mitigate climate change and protect their critical infrastructures. Fundamentally and actively cities need to engage on developing strategic responses to the constraints and opportunities of climate change and resource constraints as well (UNEP, 2000). This can be achieved by new strategies of reconfiguring them and their infrastructures in a way that helps to maintain their security, their reproduction and what needs to be done for more ecological secure urbanities.

This process must take into consideration risks and uncertainties which characterize the complexity of climate change, the limited resource availability in developing countries and start to form a knowledge ground which helps to support new design strategies which eventually protect cities (Krafft et al., 2002). Therefore the definition of urban infrastructure should not only address basic services but should be expanded to the inclusion of climate change impact and hazard management to secure the build environment (WBGU, 2003). A rise of two degrees and associated modifying weather patterns, the change in precipitation patterns, sea levels changes, storm frequencies and floods will affect all cities and is expected to be more severe in coastal zones. An increase of stronger storms and extreme weather events have been observed more frequently during the past decades (Ozor, 2009).

23

Precipitation patterns have changed, where some areas receiving more rainfall and others less (Webster et al., 2005). It is very likely for climate change to cause impacts on ecosystems and their embedded species, as it is observed in the case of coral bleaching, damages of wetlands and coastal ecosystems and social impacts will also directly affect urban cities. The agricultural sector is largely expected to be vulnerable to direct and large impacts from gradual changes in temperatures and changed precipitation patterns (Mendelsohn, 2008). From this background, the argument to include an eco-infrastructure-based approach for climate change strategies gains more importance. As eco-systems play a critical role for building resilience as well reducing the vulnerabilities of cities and economies, enhanced management and protection of their biological habitats and resources can contribute to mitigation and to solutions while cities and nations struggle to adapt to climate change. A new risk management paradigm related to climate change is needed, while taking a range of possible future climate conditions into consideration and their associated impacts. Some of these climate change impacts might be a part of past experiences, trends, variations and this indicates not to wait until uncertainties have been reduced before considering adaptation actions. Taking actions now to increase the city’s security and adaptive capacity, constitutes an insurance against to an uncertain future (Jones et al., 2012).

24

CHAPTER THREE

RESEARCH METHODOLOGY

3.1 Introduction

This chapter outlines the methodology employed during the survey to achieve the specific objectives set in chapter one. The first part presents study location, population, physical and human geographical features and the justification of the study. The second part describes research design and its application to the relevant of the study objectives. In the third part, consists out of research methods, sampling procedures, data collected technique, data collected tools, processing and data analysis are described.

3.2 Study areas

In this study, two sites were selected, first site, Dar es Salaam city in Tanzania is selected to conduct an inventory assessment of existing sanitation with a view to evaluating retrofit feasibility for the development of sustainable wetland-based sanitation. Also to identify institutional and policy constraints that critically affect sustainable developments in the urban wastewater management while achieving climate compatibility.

Figure 3.1: Location of two cities in East Africa for research case study, source; Google earth

3.3 Study location

Dar es Salaam is one the region among twenty five regions in Tanzania mainland. D’Salaam is the economic centre and richest city in Tanzania. The city is located in the eastern part of the country and it has three local administrative municipalities namely Kinondoni on the north, Ilala in the central and Temeke municipality on the southern part.

The Dar es Salaam had population of 4.4 million people as of the official 2012 census. Dar es Salaam is located at 6°48’ South, 39°17’ East (-6.8000, 39.2833) longitude, with an area of 1,350 square kilometres (km²), it occupies 0.19 percent of the Tanzanian mainland. The region is boarded by two rivers, Mpiji River to the north and Mzinga River in the south. In eastern part is boarded with the Indian Ocean.

25

Figure 3.2: Map of Dar es Salaam city; source Google earth retrieved on 07/02/2014

3.4 Sanitation coverage

3.4.1 National level

From House Baseline Survey (HBS) 2007 shows that most households have access to at least basic sanitation facilities (figure 3.2). However, the vast majority of traditional pit latrines, which are the most common type of household facility, according to WHO/UNICEF Joint Monitoring Program (JMP) standards, and unhygienic, The JMP estimates that, nationally, only 24% of people in Tanzania have access to an improved latrine (JMP, 2010), and that coverage is 21% in rural areas and 32% in urban areas.

Figure 3.3: Sanitation Status and coverage in Tanzania, Source: JMP (2010), statistics refer to ‘unimproved pit latrines’ rather than ‘pit latrines’.

However, DHS data, which has a strict interpretation of improved sanitation and came out after the study was carried out, reduced the JMP access estimate of 24% to 13%. To put this into perspective, this means that around 35 million Tanzanians do not have access to the of sanitation facilities that provide an effective barrier to disease.

26

3.4.2 Overview of Dar es Salaam Sanitation

In Dar es Salaam there has been little change in the propositional of households accessing sanitation and sewerage services since 1990s. Fifure 3.4 shows that close to 99% of the population in Dar es Salaam report using a toilet of some sort, with over 80% of the population using pit latrine, while 10% use flush toilets and 8% use VIP latrines (HBS, 2007).

Figure 3.4: Sanitation coverage in Dar es Salaam

Table 3.1: Study area population and size of Municipalities in Dar es Salaam

Manicipality Annual growth

rate

Population (2012)

Urban (%)

Rural (%)

Area (km²)

Population density

(people/km²)

Kinondoni 4.3% 1,775,049 95% 5% 527 3,368

Temeke 4.6% 1,368,881 94% 6% 656 2,087

Ilala 3.9% 1,220,611 93% 7% 210 5,812

Total 4.3% 4,364,541 94% 6% 1,393 3,756

Sewerage services in Dar es Salaam are provided to a small percentage of the population. While 10% of the population is connected to sewerage networks, only 3% of the wastewater collected throughout the networks is treated through stabilization ponds, 7% is discharged directly into the sea outlet. Figure 3.5 shows that the sewerage network is concentrated in the city centre and new developed areas are far from the nwtwork system.

27

3.5 Research Design

The overall research objective of this research study was to propose a Climate Change Compatible process design of a Wetland-Based Sanitation for sustainable Cities in East Africa (as exemplified by cities of Dar es Salaam, (Tanzania) and Mombasa, (Kenya).

Climate change compatible wetland-based sanitation for sustainable cities (eco-city)

Inventory assessment of existing sanitation situation in the study areas.

Carrying out case study by conducting interventions and questionnaires to HH leaders,

public officials and stakeholders for wastewater disposal and management,

conduct field visit observation in Dar es salaam.

Carrying out case study by conducting interventions and questionnaires to HH leaders,

public officials and stakeholders for wastewater disposal and management,

conduct field visit observation in Mombasa.

Review eco-city related development in Mombasa with a view to evaluating retrofit feasibility of

development of sustainable wetland-based sanitation in Dar es Salaam.

To evaluate retrofit feasibilty development of sustainable wetland-based sanitation in Dar es Salaam

Field visit and observation, study existing development of

sustainable wetland-based sanitation in Mombasa

Performance evaluation of wetland-based sanitation at Hacienda eco-city Mombasa

Basing on collected data for wastewater quality to analyse

the performance of constructed wetland (HSSF) for

BOD, COD, TSS, NO3-N, NH4-H, P, TC, pH, etc.

Field study and observation, interviews with plant managers and laboratory supervisor, data

collection of existing constructed wetland-based sanitation system.

Analysis of institutional structure of wastewater collection, disposal and

general environmental management in Dar es Salaam.

Provide recommendations to institutional system for sustainable operations and management of proposed

system.

Interviews and secondary data collection in related stakeholders

and available literature

SWOT analysis of the proposed system.

Figure 3.5: Overall conceptual research plan.

28

3.6 Research Methods

The study was used both primary and secondary data collection techniques. Although urban wastewater management and environmental degradation are unique to all three Municipalities in the city of Dar es salaam and Mombasa city. Furthermore, baseline survey has been carried out and sufficient data collected and analysed in both cities while concentrating on wards which are situated near the treatment cites where substantial upgrade of the infrastructure, drainage, sewerage and water supply has been carried out.

3.6.1 Sampling

The research study used simple random sampling technique to select households for interviews whereby a size five (5) percent of the households from each of the three wards was sampled. 5% of households were chosen as a good representation in each ward (Kothari, 2005). From each sampled wards, individual households were randomly selected. Ward leaders (ward executive officers) WEO facilitated the selection of households by providing lists of households in their wards. These lists facilitated the application of random sampling for the study. The following formula was applied to determine the sample size from the list of households.

Sample Size = Total Number of Households in the Ward/ 100*Percentage of Sample Size.

Households Sample by Wards

Table 3.2: Households sample size carried out in Dsm, Source: field survey 2013

Wards Number of Households in the Ward

Households Sample in the Ward (5%)

Mabibo 537 26

Mikocheni 287 14

Vingunguti 524 26

Total 1348 66

3.6.2 Data Collection Techniques

Both primary and secondary data collection techniques were used to in the study. The data collection techniques include household surveys, Participatory Urban Appraisal (PUA), key informants interviews, interviews with wastewater treatment and disposal stakeholders, visiting institutions, field observations and literature review. Data collected ranged from livelihoods data, direct observation data (settlements, wastewater treatment cites, CWs, WSPs) and data collected by taking photographs etc.

29

Figure 3.6: The conceptual framework for data collection.

Problem identification selection of study areas

Scope and objective setting

Theoretical background Primary data Secondary data

Literature review

� Wetland-based sanitation

� Climate compatibility � Sustainable cities

Field survey

� Questionnaires � Interviews � Field observations

Data collection form Government institutions, organizations and NGO'.

Analysis and discussion

Conclusion and recommendation

30

3.6.3 Household Surveys

Household survey were conducted to gather livelihood data but also environmental data. These household surveys were conducted through structured questionnaires and were administered to the 5% of the households in each ward (Table above). This technique helps to get household data quickly.

3.6.4 Participatory Urban Appraisal (PUA)

In each ward one PUA meeting was conducted in order to introduce the researcher and research themes to the ward residents. Also PUA meetings, through focus group discussion (FGD) were used to gather socio-economic and environmental data and taking the photographs necessary for this study. The gender balance were taken into account during the group discussion in order to reduce bias in type of data collection.

Table 3.3: Participatory respondents of the ward residents, Source: field survey 2013

Ward

Respondents

Total Male Female

Mabibo 15 12 27

Mikocheni 13 12 25

Vingunguti 14 12 26

Total 42 36 78

3.6.5 Key Informants and Institutional interviews

Interviews through structured and non-structured checklist were used to collate data from five institutions and eight key informants (six elderly made and two female). The institutional interviews were conducted to three District water engineers, Districts Environmental engineers and Districts natural resource officer.

3.6.6 Direct Field Observation

Direct field observation by the researcher was used to find out the understanding the real management of wastewater urban centers to record the tangible and intangible information representing both qualitative and quantitative data parameter. It was imperative way to compare the respondents’ responses and the observation.

3.6.7 Literature Review

Literature review was carried out and involved the review of various published and un-published working documents on climate compatible wetland-based sanitation from the libraries of the University of Dar es Salaam, IRA documents unit, Tanzania Bureau of Statistics library, Vise-President Office-Environment and Poverty Divisions, etc were used in collecting secondary data. The aim was to gain insight into policies that address the mitigation measures and adaptation strategies on CC compatibility impacts for the purpose of achieving sustainable development.

31

3.6.8 Data Processing and Analysis

Collected of raw data, composed of categorical and continuous, was first sorted, edited, coded and then entered into a computer spreadsheet and Statistical Package for Social Science (SPSS). The data was then initially analysed using MS Excel Programme. Then the response rate was determined of each item in the questionnaire and the overall percentage of returns from the sample size, where necessary appropriate graphical representation were made.

The initially analysed data was finally tested to draw inference, leading to a series of conclusions and recommendations. Nonparametric measures were used to analyse categorical set of data by use of logistic regression models and log linear models. Continuous scale data were analysed by parametric measures (t-test, ANOVA, and regression) to determine the relationship and perception of people on wetland-based sanitation and environmental impacts and subsequently testing the hypotheses.

3.7 Second case study area in Mombasa

The second study area was at Mombasa city in Kenya, the site were selected in order to conduct an inventory assessment of existing sanitation situation, also to review eco-city-related developments and evaluate the performance of wetland-based sanitation while focusing on achieving climate compatible development at Hacienda Holding corporation estate. The city had a population of 1,239,370 as per the 2009 census and is located on Mombasa Island and sprawls to the surrounding mainland. Mombasa city is located in coastal province of Kenya, its geographical coordinates are 4°2’0” South, 39°40’0” East. Mombasa province is divided into four divisions namely Mombasa Island, West Mainland, North Mainland and South Mainland division.

While conducting my case study in Mombasa the following procedures were employed to obtain the wide range of data needed to achieve the specific objective of this study.

Figure 3.7: Map and location of Mombasa city, source Google earth retrieved on 07/02/2014

32

3.7.1 Residential solid and liquid waste sampling

To understand the quantities and characteristics of residential solid and liquid waste produced, 28 households in all four divisions which are Mombasa Island Division, West Mainland Division, South Mainland Division and North Mainland Division were involved in sampling process. Seven households in each division were identified to participate in a sampling study. The snowball method were used to select households to be considered in the survey, the few households were first selected before they can be asked to suggest more participants. Selections of households were picked randomly by choosing throughout the area, with an equal number of households coming from each of four divisions. The model of household selection in the area for this study were also based on its accessibility to the author as well as the availability of the wastewater sewerage networks service and the population demography that is a rather accurate presentation of the average population in Mombasa.

This study found that sewerage networks is available only in two divisions Mombasa Island and West Mainland, were the sewerage network is connected to the treatment plant at Kizingo in Mombasa Island Division and Kipevu treatment plant at Westland Division. The remaining two divisions namely North and South Divisions they have neither sewerage networks nor treatment plant, they are depending on onsite sanitation mainly basing on pit latrines and septic tanks. Solid waste from each household was collected on a daily basis from 9:00-10:30 am for a week. After collection, they brought them at specific selected site where they get separated into five major components such as (organic, non-organic, non-recyclables and recyclables and weighed. There are several companies and groups which are employed in solid waste collections from the households till to the Mackinon market collection dump site where local scavenger who search for recyclables waste material for a living.

3.7.2 Conduction of Interviews

To understand the difference aspects of residential solid waste and wastewater collection and management in Mombasa, interviews were conducted through various stakeholders dealing with environmental quality control were identified. The aim was to acquire insight views as well as to supplement the information gained or obtained from structured questionnaires. Open-ended interviews also revealed the emotional and perceptions of the various parties of the current situation and various challenges they face.

Table 3.4: The stakeholders targeted to be evolved in interviews were divided as follows;

Category No. of respondents

Mombasa Water Supply Company (MOWASCO) 2

NGOs invested in eco-city in Mombasa i.e Hacienda Eco-city 2

Mombasa residents and Street waste pickers and scavengers 10

Mombasa city council staff, i.e department of environmental protection and wastes management.

2

33

3.7.3 Standard Questionnaires

To understand the existing sanitation practices of solid and liquid waste management on the household level, questionnaires with both open-ended and structured questions were utilized. All the questionnaires were administered to households by the author to ensure an accurate understanding of the questions by the respondents. A total of 18 households were surveyed. (See Appendix D for a copy of the questionnaires).

3.7.4 Field Observations

To understand clearly the DEWATS practices and operations in the municipality, observations and photography were used. Walk-through was done in all divisions of Mombasa. The author also spend many hours at various collection and wastewater treatment sites to observe on going activities surrounding the residential solid waste. On top of that, a day participation observation was done by going around with a municipal trucks for its daily operation that include visit to the various collection sites and dump sites in Mombasa municipality.

The recording of the daily life related to SWM was a good way of conceptualizing of the data and the information gathered from survey participants. Furthermore, the hazards information on living status and occupational of the different actors involved especially in SWM, as well as the environmental issues surrounding waste management could be clearly understood.

3.7.5 Secondary sources of data

A critical review of relevant literatures through various researchers and organisations provided the important background on the current sanitation situations in Mombasa. The research involved many interactions with human subjects.

All subjects involved in the different components of this research study were advised prior to their participation regarding the purpose of the study, and were informed that their involvement is voluntary and they can terminate their participation at any point in time during the study. The interviews and survey were also conducted in location chosen by subjects, at times most convenient to them. Finally, subjects were notified that they need not attempt to answer any questions that make them feel unhappy, and that the author has to make sure his presence before, during and after the intervention by person to answer any farther questions or doubt that the subject may have had.

3.7.6 Limitations of this study

There are many limitations that the author faced in this study. First, the lack of enough time and resources means that studies like to conduct inventory of the existing sanitation situation needs time and resources to compose sampling of solid and liquid wastes and residential survey were not able to reach many households in all four divisions of Mombasa. Second lack of financial support, means that conducting a survey at a place where never been and the people not know your background they normally asked to be paid so that they can participate in your study also to stay at a place where you don’t have any relatives you need to spend a lot of money to pay for hotel accommodations which was a big limiting factor to guide the author to spend very few weeks staying at study area. Third, some of the key informants particularly the Mombasa city council management were particularly hard to reach, thus secondary resource had to be used to gather the information needed.

34

Finally, the absence of data base for storage of information at the various departments and personnel involved in solid and liquid wastes management within Mombasa municipality was also a major challenging issue.

3.8 Hacienda Eco-City in Mombasa

The research study was also carried out at Hacienda Holdings Corporation Limited (Hacienda Eco-City) which is fully ecological environmental friendly housing estate located at Makirunge area within Northland Division in Mombasa city.

The Hacienda eco-city project site is covered a total of 500 acres and also the developers of Hacienda Eco-City emphasized that, the designed buildings have been constructed by considering best use of eco-friendly renewable energies from different sources. The project’s was implemented to include the development of wetland-based sanitation for biological treatment of wastewater, harvesting and recycle runoff water for the household use, nutrient reuse and planting of 20,000 tree nursery that is providing greenery in the eco-city. The aim to conduct the case study at Hacienda was to collect data for wastewater parameters so that to analyze the performance efficiency of the existing constructed wetland system used for wastewater treatment.

Figure 3.8: Map of Mombasa in the coast province, Kenya showing Hacienda eco-city at Mwakirunge area, retrieved on 02/02/2014, source; http://www.mombasa-city.com/index.htm.

3.8.1 Study site and sampling

Sampling was conducted on the existing system at Hacienda estate which comprises of septic tank for secondary treatment that is working also as equalization basin followed by secondary constructed wetland which receives influent from the secondary septic tank and finaly tertiary constructed wetland for final polishing which ultimately discharge effluent into special storage wetland for further use in irrigation, fish breeding, recreations and landscape betterments.

Hacienda Eco-city in North Mainland Division Mombasa

35

The constructed wetland (CWs) was planted with phragmites mauritianus plant species in each m2 with four plants and they are used for the wastewater treatment generated from the individual househould septic tanks.

It has three units, an equalization basin or secondary septic tank and two planted cells of the rectangular shaped constructed wetland covering a surface of 120 m2 each and a depth of 0.5 m. It is built downstream of the secondary septic tank to allow gravity flow and lined with stronger sheets made of polythene materials. The sewage flow was was adjusted by using a regulating mechanical cevice or gate valve to ensure constant inflow and a retention time of about 9 days.

Sampling was taken on weekly basis from September 2013 to November 2013 making a total of 10 weeks for sampling visits. During each sampling period, six samples were collected (three from inlets and three from outlets) means two from each cell, one in each inlet and one in outlet of the three cells by using sterile sampling bottles of (500 ml). The bottles were kept in ice cooled box and then after was transported to the laboratory of Environmental Sciences and Water Resources Department at the Pwani University College in Mombasa, for the analysis of Biochemical Oxygen Demand (BOD5) and other nutrients. In addition, pH and temperature of the influent and effluents were measured on site using a portable pH meter and an alcohol thermometer, respectively. All collected data were secondary data since during sampling and analysis period I was not yet started my research field work.

3.8.2 Statistical and Laboratory Analysis

Indicator bacteria

Analysis for Fecal coliforms (FC) and Escherichia coli (EC) was done using membrane filter technique according to standard methods (APHA 1998). Thus, an amount of 100 mls of diluted samples (inlets and outlets samples were diluted 1000 and 100 times mls respectively) were filtered through a membraine filter (Whatman, 47 mm Dia. And 0.45 µm pore size). The membrane filters were removed aseptically from the filter assembly (Sartorius AG, Goettingen, German) and placed onto agar media in pre-prepared plates. The media for FC and EC were Fecal Coliform Agar base (mFC) and E.coli selective chromogenic media (MERCK and CONDA), respectively. The plates were then incubated at 44.5 ± 0.50C for 24 hours. Blue and yellow colonies in mFC were counted as fecal coliforms and E.coli respectively. When E.coli Chromogenic argar media were used, blue colonies indicated E.coli and pale yellow/reddish colonies were fecal bacteria (Manafi et al., 1989). The numbers (cfu/100 ml) were computed from mean values of duplicates and the dilutions factors used. However these data for Fecal coliforms (FC) and Escherichia coli (EC) was not used for testing the performance efficiency of the studied Constructed wetland because there were some missing weekly data in which if used it could not bring the desired or expected outcome of the system.

36

Biochemical Oxygen Demand ( BOD5) and Inorganic Nutrients

Biochemical Oxygen Demand test was conducted using dissolved oxygen (DO) test meter such as (model YSI 5100), following the standard methods as stated in APHA (1998). Inorganic nutrients (phosphates and nitrite/nitrate) determinations were performed according to standard method described in UNESCO (1993).

The onsite analysed data were collected from Hacienda Holding Cooporation Limited (Hacienda Eco-City) at Makirunge area Mombasa. These data was analysed at Environmental Sciences and Water Resources Department at the Pwani University College in Mombasa has have been previous stated and was conducted out to record wastewater rates, ambient temperatures and wastewater temperatures. Collected wastewater samples were carefull stored and analysed in order to find out the performance efficiency of constructed wetland if they are able to mitigate the impacts of climate change through final discharging required international and local standards. The samples were analysed for multiple parameters covering the spectrum of physical, chemical and biological water quality parameters. In this study domestic wastewaters were analysed for pH and Electrical Conductivity (EC), Fecal coliforms (FC), Escherichia coli (EC), Total Dissolved Solids (TDS), Biological Oxygen Demand (BOD5), Nitrate Nitrogen (NO3-N), Ammonia Nitrogen (NH3-N), and Phosphates (PO4). The Standard Methods for the Examination of Water and Wastewater, (1998) of American Public Health Association (APHA), were used for analysis.

37

CHAPTER FOUR

RESULTS AND DISCUSSION

4.1 Inventory assessment of existing wetland-based sanitation in Dar es Salaam and Mombasa city through related stakeholders was conducted as follows;

4.1.1 Current Sanitation in Dar es Salaam city (Tanzania)

Introduction

Sanitation is the process that involves collection, transportation and safe disposal of human excreta or domestic waste for the purpose of improving hygiene (person and environmental). The objective of proper sanitation is to improve human health by preventing transmission of communicable and non-communicable diseases and to promote aesthetic environment. It involves all strategies used to solve problems raised by excreta, solid and industrial wastes and runoff water excluding production and distribution of drinking water (Black, 1977).

Sanitation Situation in Dar es Salaam

Dar es Salaam is the largest city in Tanzania and the third fastest growing agglomeration in Africa. In 2000 it accommodated 33.7% of the mainland urban population and Kinondoni was the most populous municipality in the city (UN Habitat, 2010c). While Tanzania’s urban growth rate is expected to be 4.5% between 2015 and 2020, in Dar es Salaam it is projected to be higher (UN (United Nations) 2010). Like in most rapidly growing cities of East Africa region, unplanned settlement are growing rapidly and tend predominant “mode of urbanization” (Roy, 2005). Many studies indicate that about 70% of Dar es Salaam’s population live in informal settlements (Kombe, 2005) and (Lupala, 2002). Other scholars, like (Kironde, 2005), argue that more that 80% of the building in Dar es Salaam are located in unplanned areas (Hill, 2010). About 60% of the health risk reported cases in Dar es Salaam, are typical from unplanned urban centers, these cases are related to groundwater contamination from pit latrines (Chaggu et al. 1993). However, disposal of excreta has to be considered both socially and technically. As per the past findings proved that, optimum attention is need to adhere with social aspects otherwise every technology implemented will prove failure.

Urban growth will occur in in an environmental context that is particularly at risk. According to data collected by (UNDP, 2009) and (IPCC, 2007), the main effects of climate change in Dar es Salaam are flooding, sea level rise, drought and change in rain patterns.

Wastewater treatment is one of the strategies for water quality management. In Dar es Salaam (Tanzania), water quality management began during colonial era. Some oldest sewers were laid in in the city. Between 1948 and 1952; wastewater stabilization ponds (WSPs) began to be used in the 70’s until now.

38

The majority of the people (about 85% of urban population and generally 90% of the people in the city) use on site disposal (decentralized) systems mostly pit latrines (PL).

Only 10% of the middle and upper class populations use septic tanks, 5% of the affluent class are connected to sewerage systems and 5% of the poorest have no proper sanitation at all (Mwaikyelule 1999). However, Dar es Salaam is currently population and economic are growing rapidly, the provision of wastewater management services, do not cope with population increase in urban centers.

Figure 4.1: Model of sanitation used in Dar es Salaam as per interviewed respondents

Figure 4.2: Sewerage network coverage in Dar es Salaam as per interviewed respondents

39

The level of water pollution is high, as is evident from finding in the study area. Msimbazi River, the largest river crossing the city center of Dar es Salaam currently is polluted by many industries and domestic wastewaters which are discharged without treatment. Water in the Msimbazi River is highly polluted due to the city’s excessive reliance on on-site mode of sanitation and tendency to discharge raw domestic and industrial effluents into rivers and natural channels (Yhdegho, 1992). The wastewater in Dar es Salaam CBD ends up directly in the Indian Ocean, partially treated or untreated, from both point and non-point sources. The point sources include the effluents from waste stabilization ponds and a sea outfall (Meghji, 1989). The demand for water and sanitation (including wastewater treatment) is increasing with increased urbanization and population (figure 4.1).

In general, inadequate sanitation in Dar es Salaam; that does not correspond with an increase in population in urban areas. Outbreaks of cholera, typhus, malaria and diarrhoea are common especially during the rainy season. Currently there are emerging strategies and regulations by (NEMC) to safeguard the environment from pollution and therefore protection of public health and mitigation of environmental pollution hence reduce climate change impacts.

Waste Stabilization Ponds currently have been facing several problems related to operational and maintenances, such as blockage in manholes, overloading and leakages (Mahenge, 2002).

Frequently, the quality of effluent does not consistently meet standard effluent quality requirement for discharging or reuse because their performance vary with climatic conditions and design.

Figure 4.3: Solid waste disposals and mismanagement system (field observation in Dec, 2013).

Sanitation problems in the city arise from various cultures (many residents are migrants from up-country), poor sanitation record keeping and fragmentation of sanitation activities among various sub-sectors (Figure 4.2).

40

Others are different habits of managing excreta (some people do not want to handle and subsequently termed as faecalphobic society), inadequate infrastructure facilities to cope with the population growth (7-10% per year) compared to the national increase (4.5%/yr) and increased poverty for many city dwellers. Furthermore, people build their houses haphazardly (appr. 70% of the residents live in unplanned settlements) and use different excreta disposal facilities of various nature (Table 4.1).

Additionally, about 45% the city area has a high water table and the floods in the rainy season (Mato et al. 1997) it lacks adequate technical advice for assisting the pit-latrines users, and sludge management (Figure 4.3). The reuse of valuable resources from sludges, know-how and handling technology is very limited. The first Dsm sewerage system was constructed in the mid 1940’s, and since then no adequate operation and maintenance has been done (Uronu et al. 1997). The city did have puplic toilets in the 1960s, which fell into disuse by 1990 (Lugalla 1990). Curently, there are qute a number of privately managed public toilets in different locations of the city.

Figure 4.4: Traditional pit latrines in the study area (photo taken in Nov, 2013).

Figure 4.5: Water table at Hananasif Street (surveyed and observed in Dec, 2013).

41

The results of questionnaire revealed that, for water supply, DAWASA serves 12% of the low-income city dwellers, while, about 11% use water from public wells, 5% have in house connection, 20% utilize yard connections and 44% are getting water through neighbour’s taps.

Figure 4.6: Sanitation facilities in the study area (photo taken in, Dec, 2013).

Plate 4.7 (a)

Plate 4.7(b)

Figure 4.7: Plates (a) & (b) The facilities used to store solid waste in the cases study area

42

Figure 4.8: Contaminants in a natural drainage system which is collecting and discharging storm water/wastewater into Indian Ocean untreated (field observation in Nov, 2013).

Bathing and Anal Cleansing

According to the total number of interviewees, a habit of bathing in the same place as the pit-latrine is practiced by about 52% of the people, while, 32% use separate rooms but, the bath wastewater ends up in the same pit as for the latrine (Figure 4.4).

Figure 4.9: Percentage of respondents on the use of bathing facilities in Dar es Salaam

43

4.10: Percentage of respondents on useful facilities for anal cleansing

Emptying Sanitation Facilities

Households are responsible for emptying or moving their sanitation facilities when it becomes full. Although each Dar es Salaam’s three municipalities has nominal responsibility for waste management, they have limited equipment for this. At the time of the studies, only three vacuum trucks were deemed to be operational, two in Kinondoni and one in Ilala. As a result households have been left to find alternative options to empty their latrines. Those limited options are set out below and summarised in Figure 4.7, which also shows other modes of alternating human waste, including sewers (Bereziat 2009).

Figure 4.11: Emptying services in Dar es Salaam; Source: adapted from Bereziat (2009).

44

According to Figure 4.11; the most frequent approach consists of ‘dealing’ with the problem at least cost, i.e flushing out the latrine onto the street during rainy season. This has no direct financial cost for the households concerned but can have a substantial impacts in public health terms, as the recurrent epidemics of cholera indicate.

Households can also use manual pit emptiers, or ‘frog men’, at an estimated of Tshs. 50,000 (US$ 30) to 120,000 (US$ 75) per visit. The frequency of pit emptying depends primarily on the size of the pit and on the type of facilities. Basic latrines usually need to be emptied twice a year, while septic tanks need to be emptied once a year but require two trips to do so, which leads into more cost. Manual pit latrine emptying poses a health risk to the individuals involved and is rarely associated with safe disposal.

Manual pit latrine emptiers often dump the waste out in the street and only a few actually go and discharge the sludge to the wastewater stabilization ponds managed by DAWASCO for a fee of Tshs. 25,000 (US$ 15) per trip (Figure 4.12) below.

Sewerage system Coverage

The Dar es Salaam city populations is about 4.3ml, the sewerage system coverage is only 10% of the population, which only 170km and made of 100 to 1000mm diameter pipes and covering a total area of almost 1700 ha. The sewerage system type is separate system with combination of gravity and pumped flows which discharge its effluent into Waste Stabilization Ponds (WSPs), streams and in the sea outfalls (Table 4.1). The system is mostly concentrated in the planned area (wealthier areas) of the city. There is an integrated network in the city center, which is mostly gravity-fed and there relatively cheap to operate. A series of decentralized networks also exist, which require pumping and are therefore expensive in operation.

45

Plate (a) Tankers discharging w/water into pond. Plate (b) Reconstruction of lining in WSPs.

Plate (c) Sludge dewatering in drying bed. Plate (d) Accumulation of sludge in the 1st pond

Figure 4.12: Private tankers discharging wastewater mixed with sludge at Vingunguti Waste Stabilization Ponds (photos taken in Dec, 2013 during field visit).

46

Table 4.1: Network coverage for the existing sewers. Source; DAWASCO; Rehabilitation of Dar es Salaam Water Supply and Wastewater systems- Final Design report 2002.

Area Total Length (Km)

Manholes No. Sewer (m) per manhole

City Center, Kariakoo, Upanga (R&C)

67.8 745 91

Mikocheni (R) 7.4 163 45 Regent Estate (R)

3.7 66 56

Kijitonyama (R) 10.2 154 66 Buguruni (R) 4.2 136 31 Pugu Road (I) 3.5 44 79 Tazara (I) 5.5 103 53 Ubungo (I) 9.1 164 55 Lugalo (T) 17.2 610 28 Airwing & Airport

4.4 145 30

Ukonga (T) 2.2 58 38 Mgulani (T) 9.2 236 39 University (T) 11.2 343 33 Assorting Pumping main

11.9

Total 167 2967

Pumping Stations

The existing sewerage system served by 15 pump stations, 9 pump system discharge into WSPs and the remaining are serving the City Center, Kariakoo, Upanga and Muhimbili discharges directly into the Indian Ocean through sea outfall (Table 4.2). There 9 (nine) small sewerage networks outside the city centre that serve residential, institutional and industrial areas and discharges into oxidation ponds (or WSPs). These system are managed by DAWASCO and cover 3% of the households (DAWASA, 2008). Four of them have the necessary facilities to receive fecal sludge from the trucks (sludge from septic tank & pit-latrines

47

Table 4.2: Status of pump stations for the existing sewerage in Dar es Salaam; Source: Rehabilitation of Dar es Salaam Water Supply and Wastewater System - Final Design Report, 2002. From DAWSCO during interview in Jan, 2014).

Location Gymkhana Muhimbili Msasani Mikochen

i

Lugalo 1 Lugalo 2 Universit

y

Tazara 1 Tazara 2 Tazara 3 Airport Airwing 1 Airwing 2 Mgulani 1 Mgulani 2

Influent Flow : Average Flow (l/s) Peak Flow (l/s)

61.7 133

14.2 38.7

6 11.5

Residential

13 31

12.6 27.6

12.6 27.6

7.4 13.4

2.5 4.3

8.5 19.2

5.1 12.1

2 4.3

2.1 5

6 14.7

6.1 15.2

30.7 76.1

New Pumps + Electric Control Panel Nos of Pumps Each Pump Duty Point: Flow (l/s) Head (m) # Motor Power (kw) each

2+1

75 8 12

1+1

54 10 11

1+1

24 28 13

1+1

32 23 14

1+1

28 11 6

1+1

28 11 6

1+1

15 24 7

1+1

13 9 2

1+1

20 19 7

1+1

15 26 8

1+1

14

13 4

1+1

13 6

1.5

1+1

35 12 8

1+1

16 12 4

1+1

75 14 21

Pumping Main: Main Diameter (mm) Velocity (m/s)

450 0.94

300 0.76

200 0.76

250 0.65

200 0.65

200 0.89

150 0.85

150 0.73

150 1.13

150 0.85

150 0.79

150 0.73

250 0.71

150 0.90

250 1.53

Wet Well: 3 New Volume (m )

Retention at Peak (min) Adjust Levels Starts/Stop (Nos/hr)

140 16 Yes 8

30 9

Nil 13

19 13 Yes 9

25 13 Yes 9

15 9

Nil 13

40 8

Nil 15

15 17 Yes 7

15 19 Yes 6

30 25

Yes 5

25 28

Yes 4

15 18 Yes 7

15 19 Yes 6

18 9

Nil 14

15 16 Yes 8

40 9

Nil 14

Storm Drainage Standby Generator (kw) Lighting Oil Trap / Septic Tanks

New 26

New

New 13

New

New 15

New

New 16

New

Protection

8 New

Nil 14

New

Protection

9 New

Nil 4

Nil New

New 9

New

New 10

New

Nil 6

Nil New

New 3

New

New 10

New

New 6

New Additiona

l New Served Areas City Center, Kariakoo &

Upanga Regent Estate

Mikocheni Lugalo Barracks Universit

y

Tazara Airwing Mgulani

48

Waste Stabilization Ponds

DAWASCO is in charge of operating both wastewater stabilization ponds and the sewerage system. Most of the sewerage-related operating costs consist of pumping costs, particularly for boosters on the decentralised systems. These are kept reasonably low, however, as a large portion of the system is gravity fed.

The ponds have been undergoing extensive renovation as part of the Dar es Salaam Water Supply and Sanitation Project (DWSSP), although several of them remain in poor condition and are at risk of being surrounded by illegal settlements (N.B.S, 2007). They rely on anaerobic treatment, which is comparatively cheap (it does not require electricity, as other methods of conventional treatment do, and is mostly reliant on sunshine so it is well suited to the tropical climate in Tanzania) but demanding in terms of time required to complete treatment and land use. Given the high demand for land throughout the city, it is unlikely that more ponds can be constructed in the future.

Operating sewerage treatment and disposal

DAWASCO is in charge of operating the sewerage treatment ponds. The stabilization ponds are connected to the decentralised network systems. Some ponds also receive sludge from private tankers and manually emptiers which were Vingunguti, Mabibo, Mikocheni and Kurasini but only two of these ponds (Vingunguti and Kurasini) are currently able to receive the content of on-site sanitation facilities which have high load content that requires anaerobic treatment. Mikocheni and Mabibo which are more central waste stabilization ponds and therefore usually more demand, currently they are closed for receiving sludge from tankers (di-sludged pit-latrines and septic tanks) due to complaints from people living nearby these facilities on bad smell and odour, it is only receiving wastewater from customers who are directly connected to the sewerage system. However was being rehabilitated in early 2010, source; DAWASCO interview and field observation. (Table 4.5) below shows the performance of some of the existing waste stabilization ponds (WSPs) in treatment of wastewater.

49

Table 4.3 Performances of some of the existing waste stabilization ponds (WSPs) for treatment of wastewater in Dsm.

For the month of September, 2013.

Sampling Location of

Pond

Population Flow rates

(L/s)

Final Effluent Quality Parameters

BOD5

(mg/l)

COD

(mg/l)

TDS

(mg/l)

TS

(mg/l)

Colour

(TCU)

PO4

(mg/l)

NO3

(mg/l)

NO2

(mg/l)

FC

(Nos/100mg/l)

SO4

(mg/l)

SO2

(mg/l)

Mikocheni 161789 361 7 32 160 104 170 3.50 2.485 0.366 82 36 0.06

Lugalo Limited 44 15 24 62 75 61 1.88 0.485 0.840 737 22 0.02

Mabibo Limited 93 20 24 345 200 418 0.35 0.020 0.070 266 90 0.03

Vingunguti Unlimited 21 10 35 296 150 290 - - - <100 136 0.12

Kurasini Limited 45 8 16 216 95 163 3.15 1.924 0.924 282 216 0.04

Buguruni Unlimited 8 10 46 - 65 348 - - - <100 - -

Udsm Limited 53 13

TES for discharge 30 60 3000 400 - 45 50 10 - - -

Source; DAWASCO during interview in Jan, 2014.

50

Constructed Wetlands (CWs)

Constructed wetlands (CWs) are natural system in which wastewater is treated with aquatic plants and bacteria using natural processes for treatment of wastewater such as biological, chemical and physical processes so that to accomplish the need of environment control (Reed and Brown 1995), and (Sun, Gray et al. 1999). The substrates are made of selected course aggregates or gravel with specific sizes.

Type of Constructed Wetlands (CWs) existing in Dar es Salaam

Subsurface flow constructed wetland (SSFCWs) is the only type of CW present in Dar es Salaam Tanzania. Therefore the SSF systems is favourable in Dar es Salaam. In Dar es Salaam and the whole East African region the CWs has been used for treating urban or mixed domestic wastewater through preceded by primary treatment, in for instance a septic tank or waste stabilization ponds (WSPs), as otherwise the loading with organic solids is too high and will cause clogging and malfunctioning of the system (Kimwaga et al., 2013).

Disadvantages it may get clog if not well designed and constructed, it needs large land area to build compared to activated sludge treatment plants. However, it may depend on the type of CWs of your selection because they do differ on land requirements. In Dar es Salaam, the constructed wetlands have been implemented at schools and hospitals where land area is available (Senzia et al., 2003).

Status of Constructed Wetland in Dar es Salaam

The existing constructed wetland (CWs) in Dar es Salaam, has been implemented in education centres. At the University of Dar es Salaan CWs have been coupled to the waste stabilization ponds (WSPs) which was formally constructed for wastewater treatment and the second one is at Mbagala mission centre (MMC) where they have deployed the Horizotal Subsurface Flow Constructed Wetland system coupled with septic tanks as a pre-treatment for wastewater treatments and many other CWs has been constructed by individual clients on their premises.

Plate (a): CWs at UDSM, Tanzania Plate (b): CWs at MMC, Dsm Tanzania

Figure 4.13: Existing constructed wetlands sites plate (a and b) in Dar es Salaam city.

51

Filures and and Success of Existing Wetland-based sanitation in Dar es Salaam

Constructed Wetlands (CWs) requires regular monitoring and mainteinance to ensure it remains functional and in a ‘healthy’ condition. The operational and maintanance needs includes the requirements for safety, water management, cleanout of sediments, maintenance of structures, embarkments and wetland vegetation control and harvesting during maintenance operations.

The survey results on the operation of existing CWs which was carried out during my research study indicated that 80% of the surveyed CWs experienced various forms of operational problems. The major problems experienced was a combination of blockage and over flooding (43%) whereas blockage alone constitute 26%. Other operational problems that were observed includes leakages and seepage through the walls and cracks which all together constituted 11%. Other challenges during the operation phase are fluctuation of flows and inadequate performance monitoring of the constructed wetland systems. This is due to lack of operation, maintenaince and monitoring skilled personnel one specialised in CWs services.

Besides, successful case from users of CW in the study area indicate that CW effluents are in compliance with recommended local discharge standards. According to the analysis carried out by the University of Dar es Salaam in 2010 and other researchers, CW significatly reduce pH, BOD5, COD, and Nitrates to the recommended efflent discharge standards in Dar es Salaam. However, some mixed results were observed for Ammonia and Phosphorus removal whereby some were copliance with reguratory requirement and others were not. Other successful cases entail that CWs require minimal operation and maintenance practices and costs for running.

Figure 4.14: Over-flooding of CW at Azam Stadium in Dar es Salaam as a result of poor O&M

52

Social-Economic Factors

Social Mobilization and Awareness Rising

Social mobilization is a concept which involves the creation of a social movement initiatives in order to achieve sustainable development. The aim is to obtain major insight on solving problems related to national development in high magnitude by promoting all stakeholders from possible sectors or subsector in the difference levels of the society, mobilizing local resources and using available people’s knowledge. This will help to acquire people’s creativity and productivity while encouraging and promoting awareness (Kimwaga, at el., 2013). Social mobilization needs to involve all people in the community to participate for developments, however, sectors and levels of society they have to ensure the sustainability of the programme.

Therefore, the sustainability and implementation of CW technology in the surveyed area to be succeed, it is very important that social mobilization must be highly promoted. There is a need also to educate people and given them an attention in the implementation of the CW technology in East Africa region.

4.1.2 Existing sanitation in Mombasa city (Kenya)

Introduction

Due to the benefits of an excellent natural harbor and its strategically important position on the coast of East Africa, the city of Mombasa has had a very long and chequered history. The coast area of Kenya was originally inhabited by the African Bantu people, but, over the centuries, different groups of traders sought to impose their dominance on the town and it was continually fought over by various trading nations throughout its history.

Initially, permanent human settlement on the Island was centered in the area around the original Mombasa Harbour, on the southern side of the Island. This is the area that is now referred as the Old Town and the layout of the streets and buildings was dictated largely by Arab & Portuguese influences. The buildings and roads layouts have not changed significantly since they were originally constructed. The alleys and footpaths in the Old Town are narrow and winding and are not conductive to modern vehicular traffic.

The process of “urbanization” of Mombasa really started at the end of the 19th century with the beginning of the constructed of the railway line from Mombasa to Nairobi and onwards. At that time, the population of the town expanded rapidly, with developing taking place in all parts of Island, not only in the Old Town. Gradually, expansion of the domestic, commercial and industrial districts spilled onto the mainland. The present boundary of the Municipality of Mombasa now covers an area of around 290 km2 and it includes the four main Divisions of West Mainland, North Mainland, South Mainland and Mombasa Island.

53

Sewerage system coverage in Mombasa

The only divisions in Mombasa District in which piped sewerage systems have been built are on the West Mainland and on Mombasa Island. The West Mainland system has been continually expanded since the first sewers were built in 1952 and sewers now covers most of the developed area of this Division. In 1957 the piped sewerage system was extended to serve the Rail-Served Industrial Area. Later still, extensions to the network were provided to serve the Oil Refinery and the Refinery and Magongo Housing Estates. The Changamwe truck sewer and the Chaani truck sewer were both built around this time to connect the various secondary sewer networks to a wastewater treatment plant. The sewerage system is served by a wastewater treatment plant located at Kipevu, adjacent to Kilindini Harbour. The treatment plant and the main trunk sewers on West Mainland are currently undergoing refurbishment.

The sewerage system on Mombasa Island was built in 1962 to serve the densely populated area of the old Town and a small area of Central Business District (CBD). The system has had only minimal expansion since its initial construction. Four small pumping stations, which are located along the edge of the sewered area adjacent the sea, lift wastewater from local areas into the main gravity sewerage collection system. The Old Town sewerage system is served by the Kizingo wastewater treatment plant, which is located in the south-east of the Island as shown on Figure 4.11 below.

None of the Island wastewater pumping stations is operational due to faults in the mechanical and electrical equipment fell into disrepair many years ago and the wastewater flows arriving at the pumping stations are discharged directly without treatment to the ocean through the sea outfall pipe in the vicinity of Old Mombasa Harbour. The rehabilitation of four pumping stations and the general networks for Kizingo wastewater treatment plant is currently undergoing feasibility study and design work under two engineering consulting firms.

Mombasa has only two wastewater treatment plants; one at Kipevu on the West Mainland and one at Kizingo on Mombasa Island. But none of the pumping plants or the treatment plants is in operation due to breakdowns in the Mechanical and Electrical (M&E) equipment. Many manholes in the sewerage systems have been covered with soil or built upon, so that debris can enter into the sewers, either inadvertently or by the deliberate disposal of solid waste by local residents. Because of the failure of the M&E equipment at pumping stations and treatment plants and the poor condition of the sewer pipelines, most of the wastewater in those areas that have been provided with waterborne sanitation discharges into local creeks or to the sea without any treatment.

There are no sewerage systems on the North and South Mainlands except for minor schemes to serve Council housing estates, such as Kisauni Estates on the North Mainland and Likoni Estates on the South Mainland. Some parastatal organisations also have their own housing estates, such as the Kenya Ports Authority housing development at Mtongwe on the South Mainland that have sewerage networks with septic tank system for disposal of the wastewater.

The condition of most of those systems is very poor. Small sewerage schemes to serve individual housing estates on the Island, such as Tudol Estate, Buxton Estate, and Makupa Estate were constructed in the 1960s.

54

The individual housing estates are located at the opposite end of the Island to the Kizingo treatment site and so each was provided with its own treatment facilities. The sewers and the septic tanks in those housing estates are, generally, in very poor condition.

Existing Primary Sewerage Assets

The Primary Assets of a Sewerage System can be defined as mainly comprising of:

(i) Trunk Sewers, (ii) Pumping Stations, (iii) Wastewater Treatment Plants

(iv) Operation and Maintenance Equipment

Figure 4.15: Mombasa Island sewerage catchment and location of Kizingo and Kipevu treatment plants sites.

55

It clear that among of these two treatment plants, no one is using the common conventional process technologies could be physically accommodated on the existing Kizingo site during preparation and conducting of feasibility study in treatment processes into a much smaller physical footprint. Even with a package plant, there is a limit to the volume of wastewater that can be treated on site. The wastewater flow from the existing sewered area on Mombasa Island is 3,750m3/day, which is almost at the upper limit of the application of package treatment plants.

Sewerage Infrastructure ownership

The holder of the water and sewerage infrastructure assets in Mombasa is the Coast Water Services Board (CWSB). The Board has the legal responsibility for the provision and development of water and sewerage services within its area. CWSB has contracted out the management of water and sewerage delivery services to Mombasa Water & Sewerage Company (MOWASCO).

Population and Domestic Water Demand

The population of Mombasa District is steadily increasing in line with the overall population and urbanisation trends in the country. Results from the Kenya National Censuses obtained from the Central Bureau of Statistics (CBS) show that the District population grew from 247,073 to 939,370 between 1969 and 2009. This indicates an annual average rate of population increase in the District of 3.4% over the period. The total population of all four Mombasa Divisions is about 1,852,704 according to the 2009 National Censuses.

The demographic dynamics indicate that the populations of all of the three Mainland Divisions of the District have continues to achieve high growth rate the past thirty years, whilst the annual population growth rate of the Mombasa Island Division has been only 0.1%. In fact, the population of the Island Division has shown a slight decrease over the past ten years.

West Mainland Sewerage System

The first Sewerage System to be constructed in Mombasa was built in 1952 to serve Government Housing Estates in the Changamwe area of the West Mainland. In 1957, the piped Sewerage System was extended to serve the Rail-Served Industrial Area. Later, extensions to the network were provided to serve the Oil Refinery and Magongo Housing Estates. The Changamwe Trunk Sewer and the Chaani Trunk Sewer were both built around this time to connect the various Secondary Sewer Networks to a Wastewater Treatment Plant located at Kipevu. The original Treatment Process constructed at the Kipevu site was based upon the use of Biological Filters.

In the 1980s and 90s, the Sewerage Systems on the West Mainland were extended by the construction of additional main Trunk Sewers under Phase I of the Mombasa Sewerage Project. Newly developed areas such as Miritini Site and Service (S&S) Scheme, Mikindani S&S Scheme, and the Port Reitz area were provided with sewers and connected into the main Trunk Sewers.

Chaani Trunk Sewer and Changamwe Trunk Sewer both convey wastewater separately to the Kipevu Treatment Plant entirely by gravity and no pumping is necessary.

56

Because of the locations of the Miritini and Mikindani S&S Schemes and the Port Reitz Area, including Moi International Airport, the Trunk Sewers serving those areas required the inclusion of Pumping Stations and Rising Mains to transport the Wastewater to the Kipevu Treatment Plant. Conventional Pumping Stations with one duty and one standby centrifugal pump, and associated Rising Mains were provided on the Miritini, the Mikindani, and the Port Reitz Trunk Sewers. Because of its length and the flat topography, an intermediate Low-lift Screw Pump Station was also provided on the Miritini Trunk Sewer.

A new extended Aeration Treatment Plant, utilising an Oxidation Ditch System, was constructed at the Kipevu Site under the Phase I Mombasa Sewerage Project to replace the original Biological Filter Plant. Various contractual problems that arose during the construction period delayed the implementation of the new Plant and commissioning was delayed until year 2000. Its nominal installed capacity is 17,000m3/day of wastewater with a BOD of 560 mg/l and the design BOD/SS effluent quality standard is 20/30.

Table 4.4: Summary of Existing Trunk Sewers of sewered areas of West Mainland

Trunk Sewer Pipe Dia. (mm)

Pipe Material

Total Length (m)

No. of Manholes

Miritini Trunk Sewer

400 – 800

Steel 6,270 93

Mikindani Trunk Sewer

400 Steel 1,400 25

Chaani Trunk Sewer

1000 Steel 2,700 41

Changamwe Trunk Sewer

300 Steel 3,550 70

Port Reitz Trunk Sewer

300/400 Steel 3,660 58

Totals 17,580 287

Mombasa Island Sewerage System

On Mombasa Island, a piped Sewerage Scheme was built in 1962 to serve the densely populated area of the Old Town. This was the first phase of a strategy to provide sewers to the whole of the Island. A small area of the Central Business District was included in this first phase of the Sewerage Network.

Four small Pumping Stations located along the edge of the sewered area adjacent to the sea lift wastewater from local low areas into the Main Sewerage Collection System. A Tunnel links the sewer network with Kizingo Wastewater Treatment Plant, which was built in the South-East corner of the Island at Ras Serani. A short sea outfall, about 40m long, discharges the effluent from the Treatment Plant into the Ocean.

57

The Old Town wastewater Collection System, not including the Main Outfall Tunnel, has a total sewer network length of around 20 km, with pipe sizes varying in diameter from 150mm up to 600mm. The 150mm size pipes are made of pitch fibre and the remainder are precast concrete pipes. Almost no expansion of the Old Town Sewerage System has taken place since it was built fifty years ago. The Major Collection Tunnel that connects Old Town Sewerage Network to the Kizingo Treatment Plant has a cross-sectional area of 1.9m2. It was laid at an average gradient of 1/455 through coral at depths varying from 3.5m to 16m.

The estimated capacity of the tunnel is 3m3/s and it was clearly designed to accept the future wastewater flows from a large part of the Island, not only the Old Town.

The Treatment Plant at Kizingo was designed to provide only preliminary treatment (screening and grit removal) and primary treatment (sedimentation). The Inlet Works was designed for a Dry Weather Flow of 32,500m3/day. Construction of the Sedimentation Tanks was phased and the initial installation has a settlement capacity for a Dry Weather Flow of only 4,100m3/day. The Treatment Plant has been out of operation for many years. All the M&E equipment is missing and the wastewaters flows by-pass the Works and are discharged directly to the ocean through a 40m long outfall pipe at Ras Serani. The Outfall Pipe is broken at a point about 18 m offshore and raw sewage can be seen discharging from the broken section of the Pipe.

Small Sewerage Schemes to serve individual Housing Estates on the Island, such as Tudor Estate, Buxton Estate, and Makande Estate were constructed in the 1960s. The individual Housing Estates are located at the opposite end of the Island to the Kizingo Treatment Plant and so each was provided with its own communal septic tank and soakage pit. Tudor Estate and Makande Estate both have pumping stations to pump the wastewater into the septic tanks. Neither of the pumping stations is operational.

Solid waste collection and Management

In Mombasa city, solid waste collection and disposal are carried out by the Municipal council and private companies that have been registered for that task and individual people who collect wastes from door-to-door to the permitted designation dump site. In Mombasa there is no any specific facilities to collect solid westes, municipal and private companies they are using trucks to take away wastes to the dump site which are already collected at a certain areas. In some places where households are high or medium income, plastic dustbin was observed to be in use. They are usually strategically put in area around the house which is clearly observed to be the main source of waste such as kitchen. In some areas which is very common in Mombasa, they just use plastic bags or they just dump the weste rondomly around the building. The plastic bags are not durable and break easily when holding it, however as they get them free and easily to obtain also they are widely used. The bags would simply be given to the garbage collector whey they come to pic them. Since these bags are highly convenient, they are a form of waste themselves as they are non-recyclable and inorganic.

58

At some areas in the city of Mombasa, residents are being charged with dumping their waste at a predetermined site, where there is usually bulk containers or an open land designated by the municipal council for garbage collection purposes. It was observed that many of these sites are selected or placed near the main market such as Mackinon market. This collection method makes the job simple for the municipality as their trucks only need to visit the site to take away the wastes from the area at once. They have a schedule of collecting the trash from the area for once day every morning or twice depending on the accumulation of the trash at the collection point.

Status of wastewater management and disposal

Out of 18 households surveyed and interviewed, only 33% of them are connected to the piped sewerage services that existing in two divisions, West Mainland and Island. Of these 12 of the households are not connected to the piped system, they are managing their wastewater by using on-site sanitation normally pitlatrines and septic tanks. It is clear that pit latrines are type of toilets used by many people or communities. Pit latrines are much used by the poor families especially in North and South Mainlands where there is neither sewerage networks nor plants for wastewater treatments while high and middle class they depend on flush toilets through use of septic tanks connected to soak away pits. From the interviewed households, the respodents in all four divisions, 45% they are using pitlatrines and 55% of the households respodents use septic tanks for wastewater management.

Figure 4.16: Sanitation facilities and Sewerage coverage in Mombasa Kenya

59

4.2 Performance of the existing wetland-based sanitation in Mambasa, namely, the large scale housing estate, ‘Hasienda Eco-City’ was evaluated and results were drawn as follows:

4.2.1 Performance Efficiency of CWs on Treating Domestic Wastewater

pH & Temperature Control:

The results entail that pH values in the CW influent ranged from 7.74–7.75 with an average of 7.70±0.57. On the other hand effluent pH values for the CW units ranged from 7.59–7.75 with mean value of 7.65±0.31. The results obtained reveals that pH values in the influents varied from time to time and from one source to another possibly due to variations of alkalinity in the raw sewage. Results also entails that pH in the influent is higher than pH in the effluents possibly due to decrease in alkalinity in the CW cells. Performance wise, the results agree with effluent discharge standards as recommended by local authorities which require pH to be of a range of 5.0 – 9.0. However, the results revealed that for domestic wastewater pH is not a critical parameter as both the influent and effluent met the recommended effluent discharge standards.

Figure 4.17: Temperature & pH variations in influents and effluents (cells S1, S2 and S3) in the studied CWs.

60

Temperature and pH values in this research study is shown in Tables (4.10 and 4.11) in Appendix A, reveals that, these ranges are suitable for high microbial activities as they are within the optimal values of 6.5 to 9 for pH and between 25ºC and 35ºC for temperature (Metcalf and Eddy 1995, Prescott et al., 1996). The variations in pH and temperature may be explained by differences of weather during sampling days (i.e. presence of sunny and cloudy day and contents and amount of sewege entering in the system). Also these ranges can be attributed by the wetland system due to presence og aquatic plants and substrates (gravels) that prevent direct sunlight from reaching the wastewater as it passes through the wetland. The higher pH in effluents than in influents of the CW may be due to plants uptake of carbon dioxide (CO2) during the day by photosynthetic plants and microorganisms (Kaseva 2004, Kyambadde et al., 2005).

Biochemical Oxygen Demand (BOD) Removal:

For the assessed CW units, influents and effluents levels are shown below. The influent BOD concentrations were ranged from 57.50–1023.80 mg/l with average concentration of 443.67±61.15mg/l. The effluent BOD concentration ranged from 29.7–247.80 mg/l. The inter-average BOD concentration is 111.67±12.94 mg/l. This is equivalent to the system efficiency of 95% for BOD removal. Generally, the results entails the better performed of the CW units as the BOD in the effluents do met recommended effluent discharge standards by the local authorities at the studied area. The ovarall summary results of performance efficiencies are presented in Table 4.14 in the Appendix C.

Figure 4.18: BOD5 levels (mg/L) in influents and effluents (cells S1, S2 and S3) in the studied CWs.

61

The BOD and nutrient levels in influents were also low due to the same reasons of purification activities in the preceding stages. However, the value were similar to other Researchers reports (e.g. Bitha 2006, Seswoya and Zainal 2010). The average BOD removal efficience in this study was 95% which was much higher than the earlier value of 53.9% reported previously by Bilha (2006) from the Udsm wetland. Higher value of BOD5 removal had been reported by a number of other researchers including Teck et al. (2009) who worked in a subsurface flow wetland planted with Phragmites mauritianus who reported a removal efficiency of 96%. Also Kivaisi (2001) working in a surface flow constructed wetland system using floating macrophytes (Eichhormia crassipes), a water hyacinth species reported removal efficiency of 81%. Likewise, Ismail et al. (2008) found BOD removal efficiency of up to 85% by Phragmites mauritianus in CW in Egypt.

Apart from the removal due to microbial decomposition process of organic matter in the water column, also removal process is by sedimentation or filtration process this was reported by Watson et al. (1989). The study which was conducted in Tanzania to assess the removal efficiency of BOD in various existing Horizontal subsurface flow constructed wetland by Katima et al. (2012) discovered that BOD can be removed in domestic wastewater up to 82.7% in the wetland system planted with Phragmites mauritianus. The possible reason for the lower values in the current study as compared to other reports may be due to low level of degradable organic matter entering the constructed wetland systems as such much of it might have been reduced in WSPs systems which sometimes coupled with CWs systems. However, the organic matter content of the studied sewage was not determined and remains a subject of the future studies.

Another possible reason could be a lowered efficiency on the studied wetland due to the fact that it has been operating for many years without changing the macrophytes. A study conducted by Moshiri (1993) pointed out that the oxygen required by aerobic degradation in constructed wetland is obtained through diffusion, convection and oxygen leakage from macrophytes roots into the rhizosphere. Hence, treatment efficiency of constructed wetland for the removal of organic matter is also depend on how it supports the concentration of oxygen in the gravel bed.

Nitrate Nitrogen (NO3-N) Removal:

The results showed that characteristic Nitrate Nitrogen in raw domestic/municipal wastewater range from 14.20 – 44.45 mg/l whereas Nitrate concentration in CW effluents ranged from 21.02 – 9.04 mg/l. The influent and effluent averages were 26.56±4.50 mg/l and 14.75±0.07 mg/l respectively. This is equivalent to the efficiency removal of 78% nitrate in the specific studied CW. The results entails better performance of the CW units as the effluents met recommended effluent discharge standards by local authorities.

62

-

20.00

40.00

60.00

80.00

100.00

120.00N

O3

-N in

(m

g/L

)

Sampling dates (Sept. - Nov. 2013)

S1 S2 S3

Figure 4.19: NO3-N levels (mg/L) in influents and effluents (cells S1, S2 and S3) in the CWs.

In organic nutrient removal is controlled by similar procedure as BOD. This could be explained by the fact that nutrients in the wastewater are concentrated and bounded in organic matter, and are released slowly as the organic matter get decomposed. As per sedimentation process of organic matter in septic tank system and a retention time of 1-3 days of westewater to stay in the system, much of the nutrients may have been used while some were still bound in organic matter. This implied lower nutrient levels available in the wetland system. And this is because in the wetland system it is not recommended to treat high nutrients raw westewater coming directly from households in order to avoid the clogging of the system.

Kaseva (2004) reported that, the removal efficiency of nitrate-nitrogen of 40.3% in constructed wetland cell planted with phragmites while in the unplanted cell there were less percentage of removal. Sarafraz et al. (2009) working with subsurface flow CW planted with phragmites at Teheran University (Iran), reported removal efficiency of nitrate-nitrogen of 79% in a planted cells. All of these studies demonstrate the ability of aquatic plants in the removal of nutrients from wastewater. In some of recent studies, shows that the removal efficiency in unplaed cell for nitrate-nitrogen was low, suggesting that plants plays an important role in the nitrate-nitrite uptake from the water column. This was in contrary to observations made by Armstrong and Armstrong (1991), Brix and Shieerup (1989) and Sarafraz et al. (2009) that for the removal of nitrate-nitrogen (NO3-N), the grave-bed of wetlant system without vegetation was found to be the optimal one.

Phosphates Removal:

Laboratory analysis of wastewater samples showed that Phosphates concentration in raw domestic wastewater ranged from 53.58 – 78.19 mg/l whereas Phosphates concentration in CW effluents ranged from 47.70±1.20 – 58.51 mg/l. The influent and effluent averages were 63.43±6.00 mg/l and 53.26±10.90 mg/l respectively.

63

This is equivalent to the CW efficiency of 38% on phosphorus removal. The results entails the better performance of the CW units as the effluents do met recommended effluent discharge standards by local authorities. However, the lower percentage might be contributed by the types of substrates used and operation hydrodynamics in the individual CW units. These results entail that CW is good on the removal of Phosphates which meet recommended effluent discharge standards as recommended by local authorities in East Africa.

-

20.00

40.00

60.00

80.00

100.00

PO

4 in

(m

g/L

)

Sampling dates (Sept. - Nov. 2013)S1 S2 S3

Figure 4.20: PO4 levels (mg/L) in influents and effluents (cells S1, S2 and S3) in the studied CWs.

The phosphates removal mechanism includes chamical adsorption, precipitation in substrates, lower percentage by plant uptake and biological transformations (Kadlec and Knight 1996). The removal mechanisms for nitrate include uptake by plants and microorganisms, nitrification, ammonia volatilazation, ammonification, denitrification and cation exchange for ammonium (Vymazal 2006). The results showed that the aquatic plants played a big role in the removal of nitrate and phosphate from wastewater to corroborate other studies. Furthermore, Sarafraz et al. (2009) reported that subsurface flow CW can removal phosphorus with removal efficiency as higher as 96.12% in unplanted cells and as low as 76.65% in planted cells.

Ammonia Removal:

Influent ammonia concentrations for the assessed CW units ranged from 19.17– 71.43 mg/l with average concentration of 42.97±26.22 mg/l. The effluent Ammonia concentration ranged from 12.96 – 38.30mg/l. The inter-average Ammonia concentration in the CW effluent was 23.48±11.33 mg/l. This is equivalent to the system efficiency of 86% for Ammonia removal. Though the overall performance efficiency do meet recommended effluents discharge standards by local authorities in East Africa region.

64

-

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00N

H3

-H n

i (m

g/L

)

Sampling dates (Sept. - Nov. 2013)

NH3-N Concentration in HSSFCW

S1 S2 S3

Figure 4.21: NH3-N levels (mg/L) in influents and effluents (cells S1, S2 and S3) in the studied CWs.

Ammonia and ammonium removal in constructed wetlands is most efficient in subsurface flow CWs when nitrification is occuring. The primary limiting agent for nitification in wetlands is dissolved oxygen concentration, followed by temperature and detention time (Kadlec, 2009). During nitrification, ammonia is oxidized to nitrate in a bilogically mediated heterotrophic bacteria through aerobic reaction that require availability of a readily degradable carbon source. The rate of nitrification is temperature dependant, with reaction rate increases as wastewater temperatures increases. Nitrification requires 4.3 mg/L O2 per mg N oxidized (EPA, 2000). Denitrification can dominate nitrogen removal in subsurface flow wetlands if or when nitrate is the dominate or reduces nitrogen gas (N2) and nitrous oxide N2O through species present, it takes place under anoxic conditon (EPA, 2000). Increased BOD levels have been shown to decrease nitrification rates in wetlands due to competition for available disolved oxygen (Crites et al., 2006). The presence of gravels to the outlet of the wetland is very effective which increase aeration and approve ammonia removal.

The average ammonia removal efficiency for SSF wetlands in E.Africa is ranging between 22% to 34% with daily loads of 7.89 mg/L and 8.84 mg/L (Kadlec, 2009). Ammonia removal is pH and temperature (Wellace et al., 2006), and seasonal changes, such as lower temperature on plate decay, that decrease the amount of DO, will greatly impact system performance.

Constructed wetland system components such as the size, substrate, plant species, layout & effluent concentrations determine better performances. This study reviewed a number of wetlands systems that have achieved success in the removal of ammonia and ammonium using a combination of nutrification, plant uptake, adsorption, and ammonia volatilization through SSF systems planted with Phragmites mauritianus.

65

When compared to WHO standards, the pH of the effluents in the CWs at Hacienda remainded relatively neutral, and no pH level were observed above or below the UNEP/WHO (1997) pH guidelines for the the protection of fresh watercourses for aquatic habitat life of less than 6.5 and greater than 8.5. Although the removal efficiency of phosphates shows a lower percentage, even if they generated the final effluent which did not meet with recommended local authorities and WHO discharge standards. The lower retention time could have been caused by clogging of the system due to accumulation of solids, or channeling of raw wastewater through the wetland. However in some samples from the individual cells, the results were lower but they met standards for release into environment.

In order to adhere with stardands, it is recommended to increase retention time, and wetland size during design phase to allow more wastewater be treated to match with the amount of wastewater generated, furthermore, needs to perform a regular maintenance of the wetland to enhance sewerage treatment. Wetland treatment systems requires a longer retention time to allow more time for contact between sewege, soil, sand or gravel, and root system (Katima, 2005). It is also suggested to use wastewater from the pretreatment units or maturation in case of ponds lather than to use wastewater directly from primary treatment (septic tanks) or anaerobic ponds.

The mean values of BOD and nutrients obtained at the effluents result of CW met by the local authorities and international recommended discharge standards. The required WHO standards for discharge into the enviroments should not exceed 30mg/L for BOD5, 5mg/L for phosphate and 45mg/L for nitrate (WHO 1999, 2004) some are higher than the obtained values and some are equivalent to the obtained effluents values in this study. The combination of various ways of treatment methods may result into a best performance removal of BOD5 and other onorganic nutrients (Kivaisi 2001, Katima 2005). This suggestes the use of either septic tanks as primary treatment or WSPs and CWs in order to meet the disharge standards.

In E. Africa the use of CW has been adopted since 1990’s for wastewater treatment especially in Tanzania (Katima, 2005). When CW joined with septic tank or WSPs they usually bring best results in wastewater treatment particularly in fecal indicator bacteria and BOD5 removal.

Also these systems are of low cost and easy to maintain compared to conventional westewater treatment technologies. Basing on the results of this study, it is evident that constructed wetlands in tropical regions are efficient in wastewater treatment as already been recommended by several reseachers on these systems. Planted cells of constructed wetland perform better than unplanted one. Phragmites mauritianus aquatic plants in horizontal subsurface constructed wetland reveals in several studies and it was found to still treating wastewater and continue to be efficient. Treatment performance in the reduction of BOD and organic nutrients was demonstrated. The wetland is maintained by harvesting of plants when they reach maturity to allow regeneration, and also by clearing and uprooting of undesired plants that naturally may grow into the wetland systems. It is also recommended for the Hacienda Eco-City to construct more wetland which may be used as detention ponds for storing treated wastewater which in turn will be used for irrigation during drought period so that to mitigate climate change impacts. The results suggest that CW is a viable wastewater treatment option where conventional treatment technology cannot be met.

66

4.3 Eco-city related developments in Mombasa were reviewed and evaluated with regard to retrofit feasibility for development of sustainable wetland-based sanitation in Dar es Salaam as follows:

4.3.1 Introduction

In order to retrofit feasibility for development of the sustainable wetland-based sanitation in Dar es Salaam and in East African region at large, the climate change compatibility process design of a wetland-based sanitation for sustainable cities is be carried out.

Wetland-based saniation (WBS) is the system designed by coupling with existing or new septic tanks for domestic sewege treatment the system normally plated with the aquatic emergent species. Wastewater enters the system through distribution pipes which distributes wastewater equally to the basin and then flows through the media in the wetland system.

The climate change compatibility process design of a constructed wetland using species plants of phragmites mauritianus, for an integrated production system for the treatment of wastewater. The discharged water can be used for vegetable garden, keeping fishes, recreations and also incorporate rain water and runoff harvesting. A management plan shall also be drawn.

4.3.2 Purpose of the Design

The wastewater discharged from domestic and municipal wastewater of 1500 people is to be treated for environmental compatibility, and as an input to revenue production, through vegetable and fish sales. Treatment is to be done in order to create the environmental sustainability while mitigating impacts of climate change. The main thrust of the research study is to carry out a design proposal of an integrated production system for the treatment of the wastewater, using a subsurface flow constructed wetland, and phragmites mauritianus plant species.

4.3.3 Design Objectives:

� To proposal effective sustainable wetland-based sanitation system to improve management of sewage issue to enhance eco-city criteria by using phragmites mauritianus plant species.

� To develop a suitable design to link all the existing septic tanks to the constructed wetland via centralized secondary septic tank for treatment of wastewater.

� To reuse the treated wastewater in irrigation, recreation and income production through vegetable and fish sales hence achieving climate compatible development.

� Develop a cost effective design proposal of wetland-based sanitation for effluent treatment.

67

4.3.4 Domestic Wastewater and Effluent Quality

Domestic wastewater is mainly comprised of water (99.9%) together with relatively small concentrations of suspended and dissolved organic and inorganic solids. Domestic wastewater contribute varying amount of pollutants to the total wastewater flow. The individual activities are grouped into three major wastewater fractions: garbage disposal, toilet waste and sink, basin, and appliance wastewater.

Table 4.5: Average loading rates for domestic septic tanks and average effluent quality

Organic Compounds

Wastewater mg/l (a)

Effluent mg/l (b)

TDS 600-1000 165 TSS 200-300 70 BOD 200-300 130 COD 680-730 300 Total Nitrogen 35-100 50 Total Phosphorus

18-30 12

Sources: (a) US, EPA, 1980 (b) Otis and Boyle, 1976.

4.3.5 Design Components

The system shall have both primary and secondary treatment. The primary treatment consists of 'household septic tank' and 'secondary septic tank' acting as the equalization basin and then secondary treatment at the constructed wetland and final effluent will be polished at the tertiary constructed wetland responsible for final effluents discharge for reuse.

Figure 4.22: Design Components flow diagram

Primary treatment (Septic Tanks)

The main idea is to use the already existing individual household septic tanks in the area of implementation to act as an interceptor tanks which will also remove most of settleable and floatable solids from the wastewater and use gravity pumps.

Primary Treatment Household S/Tanks

Equalization Basin

Secondary Septic

Tank

Secondary Treatment Subsurface Constructed Wetland

Tertiary Treatment

Wetland

68

Wastewater are conveyed in the septic tank effluent through a network of small diameter plastic piping to the secondary septic tanks which will play active role in sedimentation as well as an equalization basin to enhance uniform flow into the constructed wetland and then finally into the polishing wetlands for final effluent discharge.

Recommendations are for general maintenance and improvement of the households septic tanks to be able to meet the require effluent standards, thus reducing the pollution load to the wetlands and the environment and meet climate compatible developments.

Centralised Secondary Septic Tanks (Equalization Basin)

The secondary septic tank are the tank which usually reseives or collecting wastewater from individual households septic tanks. Construction of Centralized Secondary Septic Tank shall help to traps all solids that escape from the septic tanks in the households, infiltration into the sewer due to leakages and as well as act as an equalization basin. The purpose of introducing the secondary septic tank is because the septic tanks installed in many of the households, they have poor removal of nutrients because there were poorly constructed (Hamersely, et al., 2001). Hence do not achieve climate compatibility initiatives.

A filter (with associated vasult, access riser and cover, and other standard accessories) shall be installed in the effluent side of the septic tank. A filter will further reduce solids and organic load to the Constructed Wetlands System and assure long-term protection of the wetland against septic tank upset and poor maintenance. The filters are typically cost-effective and low maintenance.

The equilization basin controlls the hydraulic velocirty, of the wastewater flow rates before entering into the constructed wetlands (CWs).

Septic Tank Effluent Disposal (STED) Schemes

This effluent sewerage strategy employs interceptor tanks (primary septic tanks) at each source of wastewater generation. It allows the use of minimum diameter in sewer effluent collection system. The interceptor tanks (septic tanks) are the major sludge handling system. The sludge separation and storage in septic tanks does not require any operation till the desludging time reached. This system is the most economical method of collecting and transporting partially treatment wastewater from all the homes (septic tanks) to a Secondary Septic Tank (equalization basin) to a Constructed Wetland for a secondary treatment and then transported to the tertiary Wetland for final polishing of wastewater. The system shall work under-gravity, no energy shall be required to pump the effluent from the various households to the equalization basin and then to the wetlands for final treatment.

69

Subsurface Flow Constructed Wetland System

Constructed Wetlands in this proposal shall be considered as 'secondary treatment step’, since suspended solids, larger particles including toilets paper and other rubbish as well as some organic matter are removed by the Pretreatment, Primary and Secondary septic tanks System.

4.3.6 Design Criteria

Wastewater Flow Rates

• Population (P): = 1500 inhabitants

• Water consumption: = 170 litres/person/day

• W/water discharge: 80% of water consumption = (80/100x170) = 136L/p/day (1)

• Greywater discharge: 75% of wastewater (75/100 x 136) = 102 L/person/day (2)

• Wastewater flow rate (Q) = Population x wasterwater discharge per person per day

= 1500 x 136 L/c/day = 204,000 L/day = 204 m3/day. (3)

Design of Septic Tank

Design criteria for two compartment septic tank

• Hydraulic retention time - > 12 hours at maximum sludge depth and scum accumulation

• Sludge accumulation rate - Depending on TSS removal rate and wastewater flow (70-100litres/person/year)

• Sludge and scum accumulation volume – Sludge accumulation rate multiplied by sludge accumulation rate

• Desludging interval - > 1 year

• Volume of first compartment – Shall be two-third of the entire volume of the tank

Therefore;

• Hydraulic retention time (HRT) = 3 days = 72 hours (assumed)

• Required volume of septic tank = Q x HRT = 204 x 3 = 612 m3 (4)

• Volume of 1st compartment = 2/3 of required volume = 2/3 x 612 = 408 m3 (5)

• Volume of 2nd compartment = 1/3 of required volume = 1/3 x 612 = 204 m3 (6)

• Depth of septic tank = 3 m (assumed)

• Width of septic tank = 6 m (assumed)

• Length of 1st compartment = Volume/ (Depth x Width) = 408/(2.7 x 6) = 25 m (7)

• Length of 2nd compartment = Volume/ (Depth x Width) = 204/(2.7 x 6) = 12.6 m (8)

70

Note: The depth of septic tank is taken as 2.7 m after reducing a free board of 0.3 m

Check the HRT after sludge accumulation:

• Sludge accumulation rate = 100 Litres/person/day

• Desludging interval = 1.5 year

• Sludge volume = sludge accumulation rate x number of users x desludging interval

= (100 x 1500 x1.5)/1000 = 225 m3 (9)

• Available volume for wastewater in septic tank = Total volume – sludge volume

= 612 – 225 = 387 m3 (10)

• HRT after sludge accumulation = Available volume for wastewater in septic tank/Average volume of wastewater = 387/612 = 0.632 days = 15 hours (Since HRT > 12 hours, the design is OK). (11)

Figire 4.23: Two compartment septic tank cross-section

Calculation of Volume of Secondary Septic Tank (Equalization Basin) Volume of Secondary S/Tank = Q*HRT (Hydraulic Retention Time) (12) From Equation (3) wastewater flow rate (Q) = 204m3/day for 24hours HRT

71

For safety reason we assume 120 hours hydraulic retention time in the Secondary Septic Tank Volume of Secondary Septic Tank = 204m3 x 5 days = 1020 m3 (13)

Subsurface flow Constructed Wetlands Design

According to GIZ (2011), there are several design parameters for designing subsurface flow CWs which are used at different points in the design calculations, depending on the type of wastewater and climate:

� Area per person in m2/p.e., where p.e. stands for “person equivalent” = (1 – 2m2/p.e)

� Organic loading per surface area in gBOD/(m2·d) or gCOD/(m2·d)

� Hydraulic load in mm/d or m3/(m2·d)

� Oxygen input and consumption (kg/d).

The best method to minimise the size of a constructed wetland in an efficient pre-treatment and the precise calculation of the actual load. The organic load to a CW (in g/d) equals the flow rate (in m3/d) multiplied by the BOD concentration in the pre-treated wastewater (in mg/L).

Sizing of the Wetland based on equation

The wetland might be sized based on the following equation;

Ah = [Qd (In C i – In Ce)]/ K BOD

Where;

Ah = Surface area of bed (m2)

Qd = Average daily flow rate of sewage (m3/d)

Ci = Influent BOD5 concentration (mg/L)

Ce = Effluent BOD5 concentration (mg/L)

KBOD = Rate constant (m/d)

KBOD is determined from the expression KTdn, where;

KT = K20 (1.06)(T-20)

K20 = rate constant at 20ºC (d-1)

T = operational temperature of the system (ºC)

d = depth of water column (m)

n = porosity of the substrate medium (percentage expressed as fraction)

KBOD is temperature dependent and the BOD degradation rate generally increases about 10% per ºC.

72

Calculation for hydraulic loading rate HLR (q) for BOD

Assumptions: Background concentration (C*) is zero Average temperature (T) is 25.1oC

• q = -KT/ ln (Ce - C*/C i-C*), (14) Where: q is Hydraulic Loading Rate (HLR) Calculating for KT for BOD: KT = K20 * θ (T-20) Where T = 25.1oC (15)

KT = 180*1.06(25.1-20) = 242.29 m/ýr (16) Calculating for Hydraulic Rate (q) in (m/yr) for BOD q = -KT/ ln (Ce - C*/C i-C*) (17) q = -KT/ ln (Ce /Ci), since C* = 0, Ci = 205.76 mg/L, Ce = 30 mg/L from analysis (18) q = -242.29/ ln (30/205.76) = 125.83 m/yr or 125.83/365 = 0.345 m/day (19) But q = Q/A, (20) Where: Q is the Wastewater Flow Rate in m3/day A is Area in m2 Therefore: A = Q/q (21) Constructed Wetland area based on BOD = (204 m3/d)/(0.345m/d) = 591.74 m2 (22)

Sizing of the Wetland based on specific area requirement per Population Equivalent (PE)

According to UN-HABITAT, (2008) CWs manual, the specific area requirement for design are shown below for calculations.

Calculation of BOD and PE specific area

• Average volume of wastewater (Qd) = 1500 x 136 /1000 = 204 m3/day (23)

• BOD5 contribution = 40 g/BOD5/pe.d (24)

• BOD5 concentration = 40 x 1000/136 = 294 mg/l (25)

Let us assume that 30% BOD5 is removed by the primary treatment units, then the influent BOD5 concentration to the wetland (Ci) = 205.76 mg/l

Effluent BOD5 concentration (Ce) = 30 mg/l (analysed value)

KBOD = 0.15 m/d

73

Substituting the value in the equation;

• Ah = [Qd (In C i – In Ce)]/ K BOD (26)

• Ah = [204 (In 205.76 – In 30)]/0.15 (27)

• Ah = 2618.69 m2 ~ 2619 m2

• Specific area per population equivalent (PE) for our HF wetland = 2618.69/1500

= 1.75 m2, design is OK. (28)

Calculation of HF wetland Bed cross section area

Dimentioning of the bed is derived from Darcy’s law and should provide subsurface flow through the gravel under average conditions. Two important assumptions have been made in applying the formula;

Hydraulic gradient can be replaced by slope, and

The hydraulic conductivity will stabilize at 10-3 m/s in the established wetland

The equation is;

• Ac = Qs / [K f (dH/ds)] (29)

Where;

Ac = Cross sectional area of the bed (m2)

Qs = average flow (m3/s)

Kf = hydraulic conductivity of the fully developed bed (m/s)

dH/ ds = slope of bottom of the bed (m/m)

Note: For graded gravels a value of Kf of 1 x 10-3 to 3 x 10-3 m/s is normally chosen and dH/ds of 1% is usually used in calculations.

Required bed cross sectional area for HF wetland is calculated as follows;

• Qs = 204 m3/d = 204/(60 x 60 x 24) = 0.00236 m3/s (30)

• Kf = 2 x 10-3 m/s

• dH/ds = 0.01

Substituting in the equation above,

• Ac = 0.00236/[(2x10-3 x 0.01)] = 118 m2 (31)

By taking the depth of wetland as 0.6 m, the width of HF wetland would be 118/0.6 = 197 m

Length of the wetland = Plan area/width = 2618.69/197 = 13.32 m (32)

It is recommended that if the width of the wetland is greater tha 15 m, the wetland cell need to be partitioned. Now lets take 13 wetlands in parallel = 197/13 = 15 m, (33)

74

Then;

• Qs = 0.00236/13 = 0.000182 m3/s (34)

• Kf = 2 x 10-3 m/s

• dH/ds = 0.01

Substituting the value in the equation,

• Ac = 0.000182/[(2x10-3 x 0.01)] = 9.08 m2 (35)

Considering the depth of the wetland as 0.6 m, the width will be 15.13 m. Lets consider a width of 15 m.

Therefore, the length of the wetland = Plan area/width/no. of wetlands = 2618.69/15/13 = 13.43 m. the design is OK. (36)

Figire 4.24: HF subsurface constructed wetland cross-section, source; CW manual 2008

75

4.3.8 Horizontal subsurface flow constructed wetland (HSSFCW) components

Plate (a) Liner Plate (b) Substrates Plate (c) Vegetation

Plate (d) Inlet structure Plate (e) Outlet structure Plate (f) Control structure

Figure 4.25: Plates (a) to (f) are wetland components; source; CWs manual Tanzania

4.3.8 Constructed Wetland system processes

Wastewater treatment in wetlands include removal of pollutants like organic material, suspended matters and other nutrients. Processes of removal of pollutants and nutrients in wetlands can be broadly classified into physical, chemical and biological processes (Sundaravadivel, 2001).

4.3.9 Operation and Maintenance

The essential elements of the operation and maintenance management system of the CWs shall include:

The Management plan

Table 4.6: Management plan for Septic tanks and Constructed Wetland

Tasks Example

Operational control Varying water level

Mornitoring Water quality, habitat, flora and fauna

Inspection Structures and embarkments

Maintenance Repair damage to the structures and control weeds

76

Septic tanks Operation and Maintenance

� The sludge in the septic tank should be removed every one and half year to two years or when the total depth of sludge and scum exceeds one-third of the liquid depth of the tank.

� Excessive quantities such as detergents, kitchen wastes, laundry wastes and household chemicals can harmful the working efficiency of the septic tank. Proper management of households wastes should be maintained.

� Non decomposed materials should be avoided to be dumped into household sewage system.

� Garbage grinders are not recommended for household sewerage treatment system

� Surface runoff water and all roof and drainage discharged separately no need of treatment or can be recycled for reuse.

Constructed Wetland Operation and Mintenance

Commissioning

Operation during this period should ensure the wetland aquatic plants or vegetation coverage. When aquatic plants are well grown up, water must be introduced and hence level may be raised respectively. If plant could not grow as per required plan, transplanting can be done for replacement.

Operation

Constructed wetlands are dynamic ecosystems that requires to be operated and well managed by skilled operator. If not, problems may occur to the wetland system which can affect its performance the problems that may rise is either hydraulically or organically overloaded, flooding and droughts, weeding and excessive quantities of sediments.

77

4.3.10 Construction costing

Table 4.7: Proposed costing for Implementation of CW and its components;

S/No. Descriptions of Components Unit Cost USD

Total Sum USD

1 Efflunts analysis for 500 households S/Tanks

@$120 $60,000

2 Improvement of 500 households Septic tanks

@$400 $200,000

3 Construction of Secondary Septic tank

$80,000

4 Design and interconnection of 500 households septic tanks to secondary s/tank then to CW

$50,000

5 Construction of Horizontal Subsurface CW

$150,000

Subtotal $540,000

6 Management fee 25% of the total construction cost of all components

$135,500

Grand Total $675,500

78

CHAPTER FIVE

CONCLUSIONS AND RECOMMENDATIONS

5.1. Conclusions

5.1.1. Inventory assessment of the existing wetland-based sanitation (defined as a hygienic management of human waste) in tho East African cities namely Dar es Salaam and Mombasa in (Tanzania, and Kenya) has yielded the following conclusions.

1. Out of all the surveyed Waste Stabilization Ponds (WSPs) & Costructed Wetlands (CWs), approx. 80% experience various forms of operational problems. Main problems experienced were a combination of blockages in inlets and outlets structures and over loading (43%) whereas blockage itself constituted 26%. Other operational problems are seepages through the walls or leakages and cracks which altogether constituted 11%. Such kind of problems prevented WSPs and CWs from performing satisfactorily hence cannot achieve climate compatible development.

2. 78% of population in the surveyed areas they do not have access to piped sewerage, due to inssufficient funding allocated to sewerage and wastewater treatment investiment which is appearing disproportionate when compared to the percentage of growing population, they are depending on on-site sanitation (Pit-latrines and septic tanks). Lack of sewarage system lead to discharging of untreated or partially treated wastewater to the environment.

3. 70% of the population in the surveyed areas live in informal settlement and more than 80% of the buildings are located in unplanned areas where the sanitation services is improper due to high water table which lead to the groundwater contamination from pit latrines hence causes health risk such as diarrhea and other water borne diseases.

4. The study discovered that, the availability of few or lack of sufficient wastewater treatment plants cause many problems of desludging and emptying of pit latrines and septic tanks, this is due to many WWTP to be out of operation, those few WWTP which are operating they get overloded by the wastewater from discharging trucks at a rate of 60 tankes per hours that increases the loads to the WWTP hence affect the hydraulic residence time (HRT) finally wastewater are discharged partially treated or untreated to the environment.

5. Out of all surveyed wastewater treatment sites, none of the treatment plant is practicing on carbon capturing, no any initiatives for neutrient recycle, renewable energy production, reuse of treated wastewater, mitigating of greenhouse gases emissions, the gases like carbon dioxide CO2 and methane CH4 are released freely to the atmosphere which can eventually cause climate change impacts.

6. Implementation of wastewater tratment system in the small community studied areas, budgets become severely strained by the costs of their wastewater collection and treatment facilities. Inadequate budgets and poor access to equipment, supplies, repair facilities and lack of technial skills preclude proper operation and maintenance (O&M).

79

5.1.2. Performance of the existing WBS in Mambasa, namely, the large scale housing estate, ‘Hasienda Eco-City’ was evaluated and the following conclusions were drawn:

1. The study revealed successful performance of the tropical HSSF-CW for the secondary treatment of domestic wastewater with respect to organic matter (BOD, NO3-N and NH3-N) with removal efficiency of 95, 78, and 86% respectively. For these parameters the quality of effluent meet the admissible local standard for discharging in surface water courses at fairly short hydraulic time with 29.7, 9.04 & 12.96 mg/l respectively.

2. Given the minimal maintenance requirement, the easy of operation and good removal performance of balk pollutants, the inexpensive wetland-based sanitation technology can help to alleviate the current wastewater management problems of discharging partially treated or untreated domestic wastewater into freshwater resources.

3. The results obtained reveals that pH values in the influents varied from time to time and from one source to another possibly due to variations of alkalinity in the raw sewage. Results also entails that pH in the influent (7.74) is higher than pH in the effluents (7.59) possibly due to decrease in alkalinity in the CW cells. Performance wise, the results agree with effluent discharge standards as recommended by local authorities which require pH to be of a range of 5.0 – 9.0.

4. The CW perfomance efficiency of 38% was obtain on phosphorus removal. The results entails the better performance of the CW units as the effluents do met recommended effluent discharge standards by local authorities which is 10.09 mg/l. However, the lower percentage might be contributed by the types of substrates used and operation hydrodynamics in the individual CW units.

5.1.3. Eco-City related developments in two different subregions of East Africa: coastal area (DSM and Mombasa) and lake Victoria area (Bukoba in Tanzania, as well as Mutukura and Kampala in Uganda) were reviewed with regard to retrofit feasibility and was concluded as follows:

1. In order for the wetland-based sanitation technology to be effectively adapted, there must be financial mechanisms in place. Financial mechanisms, in this context, mean sources of funds for both capital costs and operation and maintenance costs.

2. The retrofiting of the eco-infrastructures in Dar es Salaam and Mombasa will rebuild ecosystem services that help to reduce exposure to climatic hazards, but especially, it will help to ensure people have more of the assets needed to make urban fishing and farming livelihoods less sensitive to climate change.

3. Pollution, solid waste and wastewater problems, all aggravated by climate change require a different urban management approach through utilization of wetland-based sanitation technology to build the ecological city of the future.

80

5.2 Recommendations

1. Wetland-based sanitation technology to be successiful, it is very important that social mobilization in the intervention area be implemented. Unfortunately this is an area that has not been well given due attention in the implementation of WBS technology and therefore it could be given more focus and emphasis.

2. Additional research would be needed to strengthen the case of investing in sustainable sanitation and improve the effectiveness of the public financing in East Africa region.

3. More education is needed to be developed for treatment of pit latrines and septic tanks sludge and the end product to be reused as much as possible, this is due to the fact that in the studed areas it was observed that 52% are not aware of the use of faecal sludge as fertilizer while, 48% of the potential users (farmers and gardeners) know the nutrient potential of faecal sludge but they do not want to use since they are able to get other types of fertilizers. 94% of the respondents feel that, reuse will transmit communicable disease and 6% think there is a health effect in using faecal matter.

4. There is a need to recognise the benefits of ecosystem service in strategies for climate change adaptation and improve resilience to climate change impacts on cities through investment in nature’s eco-friendly infrastructures.

5. Citizens needs to cope better with climate change impacts and avoiding to discharging untreated wastewater in the natural water courses, where eco-infrastructures are intact or restored than where they are degraded.

6. There is a need to mobilize resources and build alliances with all stakeholders and potential partners such as political leaders, local governments, professional groups, NGOs, CBOs, educational and religious institutions, mass media, cultural group etc. for sanitation improvement through adaptation of wetland-based sanitation technology.

7. In order wetland-based sanitation technology to be effective and properly constructed the contractors and builders must be supervised by WBS specialist personnel so that to avoid incorrect levels for inlets and outlets pipes to ensure desired hydraulic residence time (HRT) requirement, provision of recommended size of substrates and avoidance of introduction of soils into the wetland system that can support the growth of undesired plants such as weeds.

8. Initiatives are needed to promote affordable and appropriate watland-based sanitation with an emphasis on reduction of greenhouse gases (GHGs) emissions, nutrients recycle and renewable energy productions so that mitigate climate change for the sustainable development of the future cities.

81

REFERENCES

Abis, K. L. (2002). The performance of facultative waste stabilisation ponds in the United Kingdom, University of Leeds.

Álvarez, J. A., Ruíz, I., and Soto, M. (2008). Anaerobic digesters as a pretreatment for constructed wetlands. Ecological Engineering, 33(1), 54-67.

APHA (1998), (American Public Health Association) Standard Methods for Examination of Water and Wastewater’s, 20th edition, Washington, D.C. pp 9-10

Ayalon et al. (2001). "Solid Waste Treatment as a High Priority and Low Cost Alternative of Greenhouse Gases Mitigation. Journal of Environmental Management 27 (5): 697-704.".

Barrs (1997). "Sustainable urban food production in the City of Vancouver: an analytical and strategy framework for planners and decision-makers. Vancouver, BC: City Farmer, Canada’s Office of Urban Agriculture.".

Bereziat, E. (2009). Partnerships involving small-scale providers for the provision of sanitation services: Case studies in Dakar and Dar-Es-Salaam, Unesco-IHE.

Burkhard, R., Deletic, A., and Craig, A. (2000). Techniques for water and wastewater management: a review of techniques and their integration in planning. Urban water, 2(3), 197-221.

Butler, D., and Payne, J. (1995). Septic tanks: Problems and practice. Building and Environment, 30(3), 419-425.

Black (1977). "Water pollution Technology. Prentice- Hall Company.".

Brix, H., Arias, C., Johansen, N.H., 2003. Experiments in a two-stage constructed wetland system: nitrification capacity and effects of recycling on nitrogen removal. In: Vymazal, J. (Ed.), Wetlands: Nutrients, Metals and Mass Cycling. Backhuys Publishers, Leiden, The Netherlands, pp. 237–258.

Brix, H., 1987a. Applicability of the wastewater treatment plant in Othfresen as scientific demonstrationof the root-zone method. Water Sci. Technol. 19, 19–24.

Brix, H., 1987b. Treatment of wastewater in the rhizosphere of wetland plants—the root-zone method. Water Sci. Technol. 19, 107–118.

Carr et al. (2004). " "Improving the Health of the World's Poorest People", Health Bulletin of the Population Reference Bureau, No 1."

Chaggu et al. (1993). "Groundwater Pollution: Majumbasita, Dar es Salaam, Final Research Report, Ardhi Institute, Tanzania, pp. 1- 38.".

CITYBLUES++ (2012). "Climate Compatible Development in Vientiane; Online Resource: http://www.cityblues.la/ (Accessed: 22.02.2014)."

Costello, A., et al. (2009). "Managing the health effects of climate change: lancet and University College London Institute for Global Health Commission." The Lancet 373(9676): 1693-1733.

Cooper, P.F., Job, G.D., Green, M.B., Shutes, R.B.E., 1996. Reed Beds and Constructed Wetlands forWastewater Treatment. WRc Publications, Medmenham, Marlow, UK.

82

Cooper, P.F., 1999.Areviewof the design and performance of vertical flow and hybrid reed bed treatment systems.Water Sci. Technol. 40 (3), 1–9.

Cooper, P.F., 2001. Nitrification and denitrification in hybrid constructed wetlands systems. In: Vymazal, J. (Ed.), Transformations on Nutrients in Natural and Constructed Wetlands. Backhuys Publishers, Leiden, The Netherlands, pp. 257–270.

Curtis et al. (1994). "The Effect of Sunlight on Mechanisms for the Die-off of Faecal Coliform Bacteria in Waste Stabilization Ponds. ." TPHE Research Monograph No.1. Leeds: University of Leeds, Department of Civil Engineering.

Crites, R. W. (2006). Natural Wastewater Treatment Systems. Boca Raton, FL: CRC Press.

Daly (1991). "Steady-state economics; Washington DC, Island Press".

DAWASA (2008). " "Baseline Survey on Impact assessment of the Dar es Salaam Water Supply and Sanitation Project". Report, DES, Tanzania, December 2008.".

Denman et al. (2007). "Couplings Between Changes in the Climate System and Biogeochemistry. 563 section 7.5.3 http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4- wg1-chapter7.pdf."

ECA (2008). "Economic Commission of Africa. Assessing Progress in Africa towards the Millennium Development Goals. Addis Ababa, Ethiopia.".

El-Shafai, S. A., El-Gohary, F. A., Nasr, F. A., van der Steen, N. P., and Gijzen, H. J. (2007). Nutrient recovery from domestic wastewater using a UASB-duckweed ponds system. [Research Support, Non-U.S. Gov't]. Bioresource Technology, 98(4), 798-807.

Environmental Protection Authority (EPA) (2003). "Provisional standards for industrial pollution control in Ethiopia, Prepared under the ecologically sustainable development (ESID) project–US/ETH/99/068/Ehiopia, EPA/UNIDO, Addis Ababa.".

EPA (1983). "Design Manual: Municipal Wastewater Stabilization Ponds. ." Cincinnati, OH: Environmental Protection Agency, Municipal Environmental Research Information.

EPA (2000). "A handbook of constructed wetlands –a guide to creating wetlands for: Agricultural wastewater, domestic wastewater, coal mine drainage and storm water in th mid-Atlantic region."

EPA. (2000). Constructed Wetlands Treatment of Municipal Wastewaters. Cincinnati, Ohio: EPA, Office of Research and Development.

EPA, U. S. (2004). "Constructed Treatment Wetland,." EPA 843-F-03-013, Office of Water.

FAO (2010b), “Climate-Smart” Agriculture – Policies, Practices and Financing for Food Security, Adaptation and Mitigation. FAO, Rome.

Fankhauser S and G Schmidt-Traub (2010), From Adaptation to Climate-resilient Development – The Costs of Climate-proofing the Millennium Development Goals in Africa.

Feachem et al. (1983). "Sanitation and Disease: Health Aspects of Excreta and Wastewater Management. ." World Bank Studies in Water Supply and Sanitation No. 3. John Wiley and Sons, Chichester.

GIZ (2011): Technology Review of Constructed Wetlands: Subsurface Flow Constructed Wetlands for Greywater and Domestic Wastewater Treatment

83

Haandel, A., Kato, M. T., Cavalcanti, P. F. F., and Florencio, L. (2006). Anaerobic Reactor Design Concepts for the Treatment of Domestic Wastewater. Reviews in Environmental Science and Biotechnology, 5(1), 21-38.

Haines et al. (2010). "Public health benefits of strategies to reduce greenhouse-gas emissions: overview and implications for policy makers. ." The Lancet, 374(9707), 2104-2114.

Hammer et al. (1989). "Wetland ecosystems: natural water purifiers? In: Hammer, D.E.(ed.),Constructed wetlands for wastewater treatment. Lewis Publishers ,Chelsea ,Michigan.": pp 5-19.

Hill, A., Lindner, C. (2010). "Modelling informal urban growth under rapid urbanisation - A CA-based landuse simulation model for the city of Dar es Salaam, Tanzania. Doctoral thesis, TU Dortmund University Available at https://eldorado.tu-dortmund.de/handle/2003/27283 [accessed, January 2014]."

Hosier, R. (1992). "Energy and environmental management in eastern African cities." Environment and Planning A 24(9): 1231-1254.

Hosking et al. (2012). "How well does climate change and human health research match the demands of policymakers? A scoping review." Environmental health perspectives 120(8): 1076.

International Union for Conservation of Nature (2012). "About Climate Change. [ONLINE] Available at:http://www.iucn.org/what/tpas/climate/about/.".

IPCC (2007). "Climate Change 2007. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. vander Linden and C.E. Hanson (eds) Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA."

IPCC. (2007). "Fourth Assessment Report. Intergovernmental Panel on Climate Change Secretariat. Geneva, Switzerland. http://www.ipcc.ch/."

Johansen, N.H., Brix, H., 1996. Design criteria for a two-stage constructed wetland. In: Proceeding of Fifth International Conference Wetland Systems for Water Pollution Control, IWA & Universit¨at f¨ur Bodenkultur, Vienna, (Chapter IX/3).

Jones et al., (2012). Perspective: Harnessing nature to help people adapt to climate change. Nature Climate Change, 2, 504-509.

Jones et al. (2010). "Dimensions of the Sustainable City; Springer, Heidelberg, London, New York, p. 3."

Joss et al. (2011). "Eco-Cities – A Global Survey 2011; University of Westminster, Online Resource: http://www.westminster.ac.uk/?a=119909 (Accessed: 18.12.2013)".

Kadlec, R.H., Knight, R.L., 1996. Treatment Wetlands. CTC Press/Lewis Publishers, Boca Raton, FL.

Kadlec, R. H. (2009). Treatment Wetlands, Second Edition. Boca Raton, FL: CRC Press.

Kallidaikurichi et al. (2010). " Developing living cities. Singapore: World Scientific."

Karanja, D. M. (2006). "Health, Diseases, and Nutrition in the Lake Victoria basin, in Environment for Development: An Ecosystems Assessment of Lake Victoria Basin, Odada, E.O., Olago, D.O. and Ochola, W., Eds., (2006), UNEP/PASS.".

84

Katima, J., et al. (2012) "Constructed Wetland Potential in the Sanitation Service Chain in Lake Victoria Basin."

Katima JHY 2005 Constructed Wetlands: A Chemical Engineering Perspective, Professorial Inaugural Lecture series No. 47, University of Dar es Salaam, Tanzania. pp. 12-13.

Kayombo et al. (2005). "Waste stabilization ponds and constructed wetlands design manual." UNEP-IETC with the Danish International Development Agency (Danida).

Keim, M. E. (2008). "Building human resilience: the role of public health preparedness and response as an adaptation to climate change." American journal of preventive medicine 35(5): 508-516.

Kennedy et al. (2011). "The study of urban metabolism and its applications to urban planning and design." Environmental pollution 159(8): 1965-1973.

Kironde, J. M. L. (2000). "Rapid Urbanisation in Tanzania: The Government’s Coping Strategies, in Ngware, S. and Kironde, J. M. L. (2000), Urbanising Tanzania, Issues, Initiatives and Priorities, DUP (1996) Ltd., Dar-es-Salaam, Tanzania, pp. 22-58.".

Kironde, J. M. L. (2005). "Current changes in customary/traditional land delivery systems in sub Saharan African cities: The case of Dar es Salaam city."

Kivaisi et al. (2001). "The potential for constructed wetlands for wastewater treatment and reuse in developing countries: a review." Ecological Engineering 16(4): 545-560.

Kombe, W. J. (2005). "Land use dynamics in peri-urban areas and their implications on the urban growth and form: the case of Dar es Salaam, Tanzania, Habitat International, 29, 113–135."

Klein et al., (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press.

Krafft, et al., (2002) Health and the Environment. Cross Cutting Issues in Global Change Research. German National Committee for Global Change Research (NKGCF), Munich.

Kyambadde, J. (2005). Optimizing processes for biological nitrogen removal in Nakivubo wetland, Uganda. PhD dissertation, Department of Biotechnology, KTH, Stockholm, Sweden. ISBN 91-7283-962-7.

Lapaige et al. (2010). "Innoversity in knowledge-for-action and adaptation to climate change: the first steps of an ‘evidence-based climatic health’transfrontier training program." Advances in Medical Education and Practice 1: 89.

Lugalla, J. L. P. (1990). "Socialist Construction and Urbanization Process: An analysis of Urban Poverty and Politics in Tanzania. In Kironde, J. M. L. 1994. The Governance of Urban

Development in Tanzania, Workshop Paper Dar es Salaam, pp. 1-42.".

Lupala, A. (2002). "Peri-urban land management for rapid urbanisation. The case of Dar es Salaam. SPRING Research Series 32, Dortmund."

Loudon et al., (2005). Septic Tanks. Model Decentralized Wastewater Practitioner Curriculum, National Decentralized WaterResources Capacity Development Project. CIDWT, Raleigh, NC.

85

Mergaert, K., Vanderhaegen, B., and Verstraete, W. (1992). Applicability and trends of anaerobic pre-treatment of municipal wastewater. Water Res, 26(8), 1025-1033.

Mahenge (2002). The study on Ecological Sanitation Systems in Dar es Salaam, BSc. Environmental Engineering Dissertation, University College of Lands and Architectural Studies (UCLAS), Tanzania. Dar es salaam, UCLAS.

Manafi et al., (1989), A combined chromogenic-fluoro-genic medium for the simultaneous detection of total coliforms and E.coli in water. Zentralbl. Hyg. 189: 225-234.

Mara, D. D. (1976). "Sewage Treatment in Hot Climates." Chichester, England: John Wiley and Sons.

Mara, D. D. (1987). "Waste stabilization ponds: problems and controversies." Water Quality International, (1), 20-22.

Mara, D. D. (1997). "Design Manual for Waste Stabilization Ponds in India. ." Lagoon Technology International Ltd., Leeds, England.

Mara et al. (1986). "Artificial freshwater environments: waste stabilization ponds." In Biotechnology, VCH Verlagsgesellschaft, Weinheim. vol. 8 (ed. W. Schoenborn),: pp. 177-206.

Mara et al. (1992). "Waste Stabilization Ponds: A Design Manual for Eastern Africa. ." Lagoon Technology International Ltd, Leeds, England.

Mara et al. (1998). "Waste Stabilization Ponds: Design Manual for Mediterranean Europe." Lagoon Technology International Ltd, Leeds.

Marais (1970). "Dynamic behaviour of oxidation ponds." In Proceedings of the Second International Symposium on Waste Treatment Lagoons (ed. R.E. McKinney), Laurence, KS: University of Kansas.: pp. 15-46.

Marais, G. V. R. (1974). "Faecal bacterial kinetics in waste stabilization ponds. ." Journal of the Environmental Engineering Division, ASCE, 100 (EE1), 119-139.

Mate et al. ( 1991). "Why a pit latrine, A manual for extension Workers and Latrine Builders, International Research Centre Netherlands 1 – 21 pp.".

Mato et al. (1997). "Tanzania Environmental Profile, Prepared for Japan International Co-operation Agency (JICA), UCLAS Tanzania, pp. 1-18.".

Mc Harg I. (1969). "Design with nature. Dockside Green; VIC: Wiley."

Meghji (1989). "Point sources of discharge of wastewater effluents from waste stabilization ponds and a sea outfall in Dar es Salaam city."

Metcalf and Eddy (1995) Wastewater Engineering: Treatment, Disposal and Reuse. Mc-Graw Hill ltd, New York.

Mitsch et al. (2000). "Wetlands. Third Edition, John Wiley & Sons: New York.".

Münch, E. v. (2008). Overview of anaerobic treatment options for sustainable sanitation systems. BGR Symposium „Coupling Sustainable Sanitation and Groundwater Protection.

Murray et al. (2010). "Designing reuse-oriented sanitation infrastructure: the design for service planning approach." Wastewater Irrigation: 303.

86

Mwaikyelule, V. (1999). "Framework for Performance Monitoring and Evaluation of Urban Water and Sanitation, Inception Report Volume 2 Annexes, Ministry of Water Dar-es-Salaam, Tanzania, Annex 3e.".

N.B.S. (2007). "Dar es Salaam water supply and sanitation project (DWSSP), preliminary baseline survey."

Nations., U. (2008). "World urbanization prospects e The 2007 revision. New York.".

Newman et al. (2008). "Cities and sustainable ecosystems; Washington DC, Island Press."

Nicholls et al., (2007) Coastal systems and low-lying areas in Climate Change 2007. Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press.

Nwaka (1992). "“Development Control and Shelter Provision in Nigerian Cities”, Habitat International Vol. 16, No. 1, pp.95-111."

O’Hogain, S., 2003. The design, operation and performance of a municipal hybrid reed bed treatment system.Water Sci. Technol. 48 (5), 119–126.

Oliveira et al. (2010). "Cities, Biodiversity and Governance: Perspectives and Challenges of the Implementation of the Convention on Biological Diversity at the City Level; United Nations University Institute of Advanced Studies, Yokohama."

Ozor, N. (2009) Implications of Climate Change for National Development: The Way Forward. Debating Policy Options for National Development; Enugu Forum Policy Paper 10; African Institute for Applied Economics (AIAE); Enugu, Nigeria: 19-32.

Parry et al., (2007). Climate change 2007: impacts, adaptation and vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, Cambridge University Press.

Patterson, RA., (1985): Rural Subdivision Based on Septic Tank Effluent Disposal. Presented to Environmental Planning for Rural Areas, 1985 New England Planning Conference, Moree. Department of Environment and Planning.

Prospects: The 2009 Revision, http://esa.un.org/wup2009/unup/, Wednesday, February 09, 2011."

Rapoport et al. (2011). "DEFINING THE ECO-CITY: A DISCURSIVE APPROACH ; Online Resource: misbe2011.fyper.com/proceedings/documents/95.pdf (Accessed: 18.12.2013) ".

Reed et al. (1995). "Small and Decentralised Wastewater Management Systems, Boston: McGraw-Hill, 1998.".

Reed, S. C. and D. Brown (1995). "Subsurface flow wetlands: a performance evaluation." Water environment research: 244-248.

Register R. (1987). "Ecocity Berkeley: Building cities for a healthy future; North Atlantic Books, California."

Reijntjes et al. (1992). "Farming for the future: an introduction to low-external-input and sustainable agriculture. London: Macmillan Education / ETC / ILEIA.".

Roy, A. (2005). "Urban informality – Towards an epistemology of planning. Journal of the American Planning Association, 71 (2), 147-158."

87

Sawyer et al. (1994). "Chemistry for Environmental Engineering,." 4th edition. McGraw-Hill Book Co., New York, NY.

SCBD (2010). "Global Biodiversity Outlook 3; Secretariat of the Convention on Biological Diversity, Montreal."

Shen et al. (2011). "The application of urban sustainability indicators–A comparison between various practices." Habitat International 35(1): 17-29.

Sleytret et al. (2009). "Diversity of abundant bacteria in subsurface vertical flow. Ecological Engineering. V.5:1021-1025.".

Sun, G., et al. (1999). "Treatment of agricultural wastewater in a combined tidal flow-downflow reed bed system." Water Science and Technology 40(3): 139-146.

Tilley, E., Lüthi, C., Morel, A., Zurbrügg, C., and Schertenleib, R. (2008). Compendium of Sanitation Systems and Technologies.

Troussellier et al. (1986). " Modelling the evolution of bacterial densities in an eutrophic ecosystem (sewage lagoons)." Microbial Ecology, 12, 355-379.

U S EPA (2004). "Constructed Treatment Wetland, EPA 843-F-03-013, Office of Water.".

UN (United Nations) (1987). "Report of the World commission on environment and development. [ONLINE]: Available at: http://www.un-documents.net/a42r187.htm."

UN (United Nations) (2008). "World urbanization prospects: the 2007 revision, UN publication,February,2008.http://www.un.org/esa/population/publications/wup2007/2007WUP_Highlights_web.pdf. Accessed 30 Sept. 2013.".

UN-HABITAT, 2008. Constructed Wetlands Manual. UN-HABITAT Water for Asian Cities Programme Nepal, Kathmandu.

UN-Habitat (2003). "The Challenge of Slums: Global Report on Human Settlements, Earthscan, London".

UN (United Nations) (2010). "World Population Prospects: The 2008 Revision and World Urbanization

UN Habitat (2010c). "Informal Settlements and Finance in Dar es Salaam, Tanzania, Nairobi, 2010."

UNDP (2009). "UNDP Climate Change Country Profiles. Tanzania, C., McSweeney, M. New and G. Lizcano, http://country-profiles.geog.ox.ac.uk, General Climate ".

UNEP (2010). "Green Economy. Developing Countries Success Stories, [Online]. Available at: :http:// www.unep.org/pdf/GreenEconomy_SuccessStories.pdf."

UNEP (2000). GEO-2000 Global Environmental Outlook. Available at: http://www.unep.org/geo2000/english/0051.htm (retrieved 14 November 2009).

UNESCO (1993), Manuals and Guides 28. Nutrient Analysis in Tropical Marine Waters.

Uronu et al. (1997). "Country Urban Environment Sanitation Status Report, Focus: Solid Waste and Human Management, Dar-es-Salaam, Tanzania, pp. 3 – 30.".

Verhoeven, J. T. A., and Meuleman, A. F. M. (1999). Wetlands for wastewater treatment: Opportunities and limitations. Ecological Engineering, 12(1), 5-12.

88

Vymazal, (2005). "Horizontal sub-surface flow and hybrid constructed wetlands systems for wastewater treatment".

Vymazal, J. Removal of nitrogen via harvesting of emergent vegetation in constructed wetlands for wastewater treatment. In: Vymazal, J., (Ed.), Backhuys Publishers, Leiden, The Netherlands, 2005, pp. 209–221.

Wackernagel et al. (1996). "Our ecological footprint: reducing human impact on the earth. Gabriola Island, BC / Philadelphia: New Society Publishers.".

Wallace, S. D., & Knight, R. L. (2006). Small‐Scale Constructed Wetland Treatment Systems: Feasibility, Design Criteria, and O&M Requirements. London, UK: IWA Publishing.

World Bank (2003) World Development Report 2003. Sustainable Development in a Dynamic World. Transforming Institutions, Growth, and Quality of Life. World Bank, Washington DC.

WHO (1989). "Health Guidelines for the Use of Wastewater in Agriculture and Aquaculture." World Health Organization, Geneva.

WHO (1999). Health-based monitoring of recreational waters: the feasibility of a new approach (the ‘Annapolis protocol’). Outcome of an Expert Consultation, Annapolis, USA Cosponsored by USEPA, Geneva.

WHO/UNEP 1997 Water Pollution Control - A Guide to the Use of Water Quality Management Principles, Publisher St Edmunds bury Press UK.

WHO (2009). United Nations Children’s Fund Joint Monitoring Programme for Water Supply and Sanitation (JMP). Progress on Drinking Water and Sanitation: Special Focus on Sanitation. UNICEF, New York and WHO, Geneva, 2008.

WHO (2009). Protecting Health From Climate Change: Global Research Priorities, Geneva, World Health Organization.

Wolman A. (1965). "The metabolism of cities; Scientific American, 213: 179–190".

Wong et al. (2011). "Eco-city Planning - Policies, Practice and Design; Springer, Heidelberg, London, New York, p. V."

World Bank (2010). "Eco-cities, Ecological cities as economic cities; Synopsis; Online Resource: http://siteresources.worldbank.org/INTURBANDEVELOPMENT/ Resources/336387-1270074782769/Eco2Cities_synopsis.pdf (Accessed: 28.02.2013)."

WSP (2002). "Water and Sanitation Sector Reform in Uganda: A Government–Led Transformation. Water and Sanitation Programme-Africa (WSP).".

Yhdegho (1992). "sanitation and tendency to discharge raw domestic and industrial effluents into rivers and natural channels ".

Zimmels, Y., Kirzhner, F., and Malkovskaja, A. (2006). Application of Eichhornia crassipes and Pistia stratiotes for treatment of urban sewage in Israel. [Research Support, Non-U.S. Gov't]. J Environ Manage, 81(4), 420-428.

89

APPENDICES

Appendix A: Performance efficiency of Horizontal Subsurface Flow Constructed Wetland at Hacienda Eco-city Mombasa Kenya.

Influent and Effluent BOD5 in (mg/L)

Time in weeks S1 S2 S3 Remova Efficiency (%)Inlet Outlet Inlet Outlet Inlet Outlet

09/09/013 984.0 311.0 311 74.0 47.0 28.0 97.019/09/013 890.3 210 210 63.5 63.5 23.8 8723/09/013 1170 49 49 33 33 29 9801/10/013 890.0 377.0 377.0 87.5 87.5 29.6 86.007/10/013 1170 47 47 43 43 39 9714/10/013 984.0 311.0 311.0 74.0 74.0 30.0 97.021/10/013 1210 244 244 69 69 35 9728/10/013 980.0 315.0 315.0 45.0 45.0 26.0 97.004/11/013 980.0 305.0 305.0 43.0 43.0 25.0 97.011/11/013 980.0 309.0 309.0 70.0 70.0 32.0 97.0

1023.8 247.8 57.5 29.7 95.0

Table 4.6: BOD (mg/L) parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

KSE for BOD5 = (40 mg/L)

S1 = Septic tank for primary treatment S2 = Constructed wetland for secondary treatment

S3 = Constructed wetland for tertiary treatment (polishing)

NB: S1…Sn = Sampling location KSE = Kenyan Effluent Standards

90

Influents and Effluents for NO3-N in (mg/L)

Dur. in weeks S1 S2 S3 Removal Efficiency (%)Inlet Outlet Inlet Outlet Inlet Outlet

09/09/013 45.51 28.50 28.50 23.50 23.50 13.10 71.019/09/013 28.6 17 17 12 12 8.1 7223/09/013 32.00 0.44 0.44 0.15 0.15 0.09 10001/10/013 106.00 26.90 26.90 20.90 20.90 10.20 90.007/10/013 43 29.5 29.5 12 12 6 8614/10/013 45.51 28.50 28.50 18.00 18.00 13.10 71.021/10/013 7.4 3.9 3.9 2.4 2.4 2.2 7028/10/013 45.97 23.45 23.45 19.00 19.00 12.50 73.004/11/013 43.50 25.00 25.00 17.00 17.00 11.00 75.011/11/013 47.00 27.00 27.00 17.00 17.00 14.12 70.0

44.45 21.02 14.20 9.04 AV = 78 KSE = Kenyan Effluent Standards, KES for NO3-N = (50 mg/L)

Table 4.7: NO3-N (mg/L) parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

Influents and Effluents for NH3-N in (mg/L)

Dur. in weeks S1 S2 S3 Removal Efficiency (%)Inlet Outlet Inlet Outlet Inlet Outlet

09/09/013 76.00 39.50 39.50 18.77 18.77 12.39 83.019/09/013 93.4 49.5 49.5 25.3 25.3 18.5 8023/09/013 83.4 49.5 49.5 18.5 18.500 12.530 8501/10/013 47.40 36.20 36.20 24.20 24.20 12.40 68.007/10/013 32.74 15.62 15.62 13.44 13.44 11.09 9814/10/013 79.31 39.50 39.50 18.74 18.74 11.33 85.0

21/10/013 76.00 39.50 39.50 18.77 18.77 10.42 86.00 28/10/013 77.00 38.67 38.67 19.20 19.20 12.98 83.004/11/013 74.00 37.00 37.00 17.45 17.45 13.50 82.011/11/013 75.00 38.00 38.00 17.30 17.30 14.43 81.0Average 71.43 38.30 19.17 12.96 86

KSE = Kenyan Effluent Standards, KES for NH3-H = (20 mg/L)

Table 4.8: NH3-N (mg/L) parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

91

Influents and Effluents for PO4 in (mg/L)

Time in weeks S1 S2 S3 Removal Efficiency (%)Inlet Outlet Inlet Outlet Inlet Outlet

09/09/013 73.40 58.00 58.00 55.00 55.00 47.30 35.019/09/013 92.25 53 53 49 49 46.4 49.723/09/013 85.4 73.3 73.3 62.6 62.600 51.300 39.901/10/013 99.20 57.50 57.50 54.50 54.50 47.05 52.607/10/013 62.28 53.17 53.17 49.27 49.27 47.29 2414/10/013 73.40 58.00 58.00 52.30 52.30 48.30 34.2

21/10/013 79.86 63.81 63.81 53.15 53.15 47.50 40.50 28/10/013 72.00 56.34 56.34 54.00 54.00 46.00 36.104/11/013 70.00 55.00 55.00 53.00 53.00 49.00 30.011/11/013 74.10 57.00 57.00 53.00 53.00 46.37 37.4Average 78.19 58.51 53.58 47.70 38.0

KSE = Kenyan Effluent Standards, KES for PO4 = (60 mg/L) Table 4.9: PO4 (mg/L) parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

Influents and Effluents for pH in (mg/L)

Time in weeks S1 S2 S3 Removal Efficiency (%)Inlet Outlet Inlet Outlet Inlet Outlet

09/09/013 7.43 7.38 7.38 7.35 7.35 7.22 2.819/09/013 7.72 7.5 7.5 7.48 7.48 7.38 4.423/09/013 7.48 7.77 7.77 8.54 8.540 8.530 -14.001/10/013 8.90 8.03 8.03 8.12 8.12 7.56 15.1007/10/013 8.9 8.03 8.03 8.35 8.35 7.76 12.814/10/013 7.43 7.38 7.38 7.22 7.22 7.12 3.5

21/10/013 7.52 7.56 7.56 8.44 8.44 8.25 (9.70) 28/10/013 7.5 7.23 7.23 7.34 7.34 7.43 0.904/11/013 7.2 7.8 7.8 7.43 7.43 7.41 -2.911/11/013 7.30 7.40 7.40 7.22 7.22 7.21 1.2Average 7.74 7.61 7.75 7.59 14.1

KSE = Kenyan Effluent Standards, KES for pH ranges = (6.0-9.0)

Table 4.10: pH parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

92

Influent and Effluent Temperature in (⁰C)Time in weeks S1 S2 S3 Remova Efficiency (%)

Inlet Outlet Inlet Outlet Inlet Outlet09/09/013 26.40 25.80 25.80 26.30 26.30 26.00 19/09/013 26.8 27.3 27.3 27 27 26.523/09/013 23.1 24.5 24.5 25.2 25.2 24.401/10/013 25.9 24.9 24.9 24.1 24.1 23.407/10/013 23.1 24.5 24.5 25.2 25.2 24.414/10/013 26.40 25.80 25.80 26.00 26.00 26.00 21/10/013 24.1 25.9 25.9 26.3 26.3 24.828/10/013 27.00 26.10 26.10 26.40 26.40 24.00 04/11/013 24.00 23.00 23.00 25.00 25.00 25.00 11/11/013 25.00 26.00 26.00 27.00 27.00 26.00

25.2 25.4 25.85 25.1

KSE = Kenyan Effluent Standards, KES for Temperature = 40⁰⁰⁰⁰C

Table 4.11: Temperature parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

Influent and Effluent TDS in (mg/L)

Time in weeks S1 S2 S3 Remova Efficiency (%)Inlet Outlet Inlet Outlet Inlet Outlet

09/09/013 358 351 351 340 340 334 6.719/09/013 354 349 349 339 339 327 7.6

23/09/013 314 295 295 269 269 239 23.901/10/013 331 321.0 321.0 305 305.0 305.0 8.5

07/10/013 314 295 295 269 269 239 23.9

14/10/013 358 351 351 340 340 334 6.721/10/013 443 283 283 261 261 231 35.5

28/10/013 356 340 340 330 330 322 9.6

04/11/013 350 345 345 340 340 336 4.0

11/11/013 365 355 355 348 348 340 6.9Average 354.3 328.5 314.1 300.7 13.3

KSE = Kenyan Effluent Standards, KES for TDS = (3000 mg/L)

Table 4.12: TDS parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

93

Influent and Effluent Electric conductivity (EC) i n µScm¹Time in weeks S1 S2 S3 Remova Efficiency (%)

Inlet Outlet Inlet Outlet Inlet Outlet09/09/013 754 796 796 733 733 73419/09/013 687 719 719 690 690 70623/09/013 555 646 646 608 608 49301/10/013 641 628 628 628 628 66007/10/013 555 646 646 608 608 49314/10/013 754 796 796 788 788 73421/10/013 935 602 602 493 493 55628/10/013 750 798 798 785 785 73604/11/013 750 790 790 780 780 73011/11/013 750 790 790 780 780 734Average 713.1 721.1 689.3 657.6

KSE = Kenyan Effluent Standards, KES for Electric Conductivity (EC)

Table 4.13: Shows Electric Conductivity parameters for wastewater influents and effluents in cell S1, S2, and S3 of the CWs.

94

95

Appendix C: Table 4.14: Presents a summary of performance efficiency results for the CW units that is treating domestic wastewater at Hacienda Eco-city in Mombasa Kenya.

CWs units Location pH BOD5 (mg/L)

NO3-N (mg/L)

NH3-N (mg/L)

Phosphates (PO4) (mg/L)

Remarks

S1 Inlet 7.74 1023.80 44.45 71.43 78.19

Outlet 7.61 247.80 21.02 38.30 58.51

S2 Inlet 7.61 247.80 21.02 38.30 58.51

Outlet 7.75 57.50 14.20 19.17 53.58

S3 Inlet 7.75 57.50 14.20 19.17 53.58

Outlet 7.59 29.70 9.04 12.96 47.70

Average Inlet 7.70±0.57 443.67±61.15 26.56±4.50 42.97±26.22 63.43±6.00

Outlet 7.65±0.31 111.67±12.94 14.75±0.07 23.48±11.33 53.26±10.90

Local Discharge Requirements

5 – 9

40

50

20

60

Efficiency (%) 95 78 86 38

96

APPENDIX D: QUESTIONNAIRES

SCHOOL OF ENGINEERING AND TECHNOLOGY - SCHOOL OF ENVIRONMENT

RESOURCES AND DEVELOPMENT - ASIAN INSTITUTE OF TECHNOLOGY

CLIMATE COMPATIBLE WETLAND-BASED SANITATION FOR SUS TAINABLE CITIES

(ECO-CITIES) IN EAST AFRICA

A CASE STUDY OF DAR ES SALAAM AND MOMBASA CITIES

INTERVIEWER’S NAME: …………………………………………………

DATE: …………………………………

A. HOUSEHOLD QUESTIONNAIRE:

HOUSE No. ………………………………………..

DATE: ………………………………………

NAME OF RESPONDENT: ……………………………………………………..

Social economic status;

1. (a) How many families live in this house? .................................................

(b) How many people are in each family? ................................................

2. Age distribution

Age Male Female

0 - 5

6 – 12

13 – 18

Above 18

3. Occupation of people

(i) Non-employed

(ii) Employed

(iii) Self employed

4. Total monthly income

(i) 0 – 150,000

(ii) Above 150,000

97

Sanitation facilities;

1. What type of sanitary facility are you using

Latrine

type

Description Super

structure

Comments

VIP Lined pit Floor

Unlined pit Walling

Vent pipe with gauze Roofing

Without gauze

Septic tank – with

cover

Without cover

WC Vent pipe with gauze Floor

Without gauze Walling

Roofing

Poor flush With water seal Floor

Without water seal Walling

Vent-pipe with

gauze

Roofing

Without gauze

Traditional

pit latrine

Lined pit Floor

Unlined pit Walling

Roofing

Other

2. How many families are using the latrine?

(i) Members of the family only

(ii) Members of other family and neighbors

3. What are cleansing materials do you use?

(i) Water

(ii) Paper

(iii) Toilet paper

(iv) Other, specify……………………………………………………………………………………

98

4. How do you do general cleanliness of your latrine/toilet

(i) By sprinkling ashes

(ii) Cleaning by water disinfectant or soap

(iii) Cleaning with water

(iv) Do not clean

5. What do you do when your latrine or septic tank is full?

(i) Dig a new one

(ii) Empty it by cesspit track

(iii) Free discharge

(iv) Other, specify…………………………………………………………………………………

6. Where do you dispose your sullage?

(i) Septic tank

(ii) To the surrounding

(iii) River

(iv) Drainage systems

(v) Other, specify………………………………………………………………………………….

7. Is there any problem you are facing in the system you are using to dispose sullage?

Yes/ No

If yes specify………………………………………………………………………………………..

8. Does your latrine/septic tank overflow during rainy season? Yes/No

9. How often do you empty your pit latrine/septic tank? ………………………………………

10. What are the problems do you face during toilet construction

(i) High water table

(ii) Rocks

(iii) Other, specify…………………………………………………………………………………...

11. What problems do you face with your latrine/septic tanks?

(i) Smell

(ii) Mosquito, cockroaches and flies breeding

(iii) Collapsing of the latrine

(iv) Other, specify…………………………………………………………………………………...

99

Solid waste management

1. What kinds of solid waste are generated from your house?

(i) Plastics

(ii) Papers

(iii) Fruit peels

(iv) Other, specify…………………………………………………………………………………….

2. How much waste do you produce per day/week? ..........................................................................

3. Where do you store your domestic waste before disposal?

(i) Open burning

(ii) Pit or buckets/sacks

(iii) Dump in open space

(iv) Other, specify…………………………………………………………………………………….

4. Is there any company or private sector involved in solid waste management Yes/No

(i) If yes, do they give this service for free? Yes/No

(ii) If No how do you manage your solid waste? Yes/No

5. Is there any company responsible for such services? And are you willing to pay?

If yes, specify………………………………………………………………………………………..

6. What kind of storage containers do you use for keeping solid waste at your house

Container Capacity

Tin

Buckets

Plastics

Boxes

Other, specify

7. Are you willing to participate in the improvement of environment in your area? Yes/No.

If yes, How? ………………………………………………………………………………………

100

B. LOCAL AUTHORITY QUESTIONNAIRE

Physical observation

1. How many people are living in this ward? ……………………………………………………..

Total No. of females ………………………..

Total No. of males ………………………….

2. Is there any existing sewerage network in this area? ……………………………………………

3. How many people have accessibility to sewerage service in this ward……………………….....

4. What is the conditions of the existing sewer system?

(i) Working smoothly

(ii) Clogging or facing blockage problems

(iii) Overflowing at the manholes, inlets and outlets

5. What are the problems associated with the existing sewer network?

(i) Diseases

(ii) Floods

(iii) Smell and odor

(iv) Pollution of grounds water sources

6. What is resident’s perception on using treated wastewater for irrigating their farms?

7. Do you are residents opt to use fecal matter/sludge as fertilizer in their farms?

8. What are your responsibility in ward level and households in general for common management

of facilities?

101

C. WASTEWATER PROFESSINALS AND OTHER STAKEHOLDERS

NAME OF ORGANISATION OR MINISTRY ………………………………………..

DATE: ………………………………………

NAME OF RESPONDENT: ……………………………………………………..

QUESTIONNAIRES

1. What is citywide potential for clean development mechanism (CDM) if the proposed approach is implemented? ………………………………………………………………………………………………………………………………………………………………………………………………………………

2. What are the other organizations which are working in wetland-based sanitation management?

……………………………………………………………………………………………………..

3. By achieving the climate change compatibility wetland-based sanitation, how much it will cost

and what the benefits will be?

……………………………………………………………………………………………………..

4. What are your recommendations to improve system for adopting climate change compatible

development and eco-city principles?

……………………………………………………………………………………………………

5. What policies are in place and what practices are applied in your eco-city to implement climate

change compatible initiatives for prevention of GHG emissions?

…………………………………………………………………………………………………….

6. What is citywide potential for clean development mechanism (CDM) if the proposed approach

is implemented ………………………………………………………………………………………………….

……………………………………………………………………………………………………

7. How much biogas can be produced if the resulting fecal sludge and plant biomass is used as fermentation substrate? ……………………………………………………………………………………………………

8. How is your city affected by climate change? Are certain economic activities, certain

communities and certain locations differently affected?

……………………………………………………………………………………………………

……………………………………………………………………………………………………

i