Title of presentation By Joseph WETHE, PhD Ir., JOSEPH.pdf · 2. Wastewater management in African...

iPAD West Africa 2008, Abuja, NIGERIA

Title of presentationBy Joseph WETHE, PhD Ir.,Lecturer & Chief of Unit for Scientific and

Technological Information Valorization (UVIST)

2iE, Ouagadougou, Burkina Faso

iPAD West Africa 2008, Abuja, NIGERIA

Title of presentationWastewater management

alternative for developing countries

IPAD West Africa 2008, Abuja, NIGERIA

1. Introduction

2. Wastewater management in African cities: Actual situation, Stakes, Challenges and Existing technologies

3. Natural systems as alternative for collective wastewater treatment plants

4. Roles and contributions of training and research institute

5. Conclusion

Plan of presentation


1. African cities �� Poor efficiency observed in existing wastewater treatment plants/systems

2. Municipalities are facing major stakes and important challenges to be raise

3. Principal Questions are:1. Which strategy according to the specific

financial, material and human resources ?

2. Which technologies (individual or collective) to be transfer in local context?

3. What contribution of training/research institute?

Introduction


Main actors for Wastewater management

Institutional Actors

Nationale scale�Technical ministries

�Parapublic Organism

Locale scale

�Municipalities

Private and associative Sectors

• Entreprises & GIC

•NGO and Associations

•Development and Financial partners

Informal sector

•Household

•Actifs « informels »

Actual situation of Wastewater management in African cities


The lack of urban management control

1. Obsolete urban management tools and an unclear institutional frame

2. Highest demographic and Fastest urban growth facing

3. Drastic decline of municipal financial, material and human resources

4. Problematic land management system �� Non adapted strategy of "house for all“ �� Development of spontaneous quarters




High standing

Medium standing

Planned/Administrated

Low standing

Periurban in densification

Spontaneous Quarters

The lack of urban management control

�� Urban typology with à 2 speeds

60% to 90%

of Population

10% to 40%

of Population


Annual demographic growth rate :

�2 X World average

�4 X Developed countries average



� Lowest level of effective sanitation added to a General deficits and Poorest performances of functioning of the existing treatment plants /systems


��350M of new persons to satisfay

The major challenge to be raise

� Achievement of Millennium Development Goals (MDG) by 2015


� Chad: 3910 cases/164 deaths� Senegal: 1187 cases/14 deaths� Zambia: 3835 cases/179 deaths

The major challenge to be raise

� Environment and aquatic ecosystem exposed to the diffuse pollution and contamination by the daily discharges of untreated solid and liquid waste

� Proliferation and persistence of diarrheic diseases, affecting children and women


� Cameroon: 2924 cases/46 deaths)� Mozambique: 15237 cases/85 deaths� Nigeria: 1616 cases/126 deaths


The greater part of inappropriate technique

1. Net dominance of individual sanitation equipments: 60% of the population (that is 80% in cities and 48% in villages) with traditional latrine, improved pit latrine, septic tanks

2. Important ratio of population, still defecating in the nature

3. Lowest rate of connected households to collective sanitation (sewer pipe and treatment plants)




About collective sanitation systems

1. Domination of Intensive wastewater treatment plants : 76% of 188 WTP listed en 14 countries in 2002-2007

2. The majority (80%) of these Intensive are abandoned some years only after their starting

3. Consequences : Row wastewaters are literally discharged in the receiving environment




Causes

1. Their expensive operating costs

2. Transportation approach by "simple imitation“• without analyzing performances factors and

local capacities to insure their effective maintenance

• Without sensitizing and implicating users ��Gap between the social practices ��"imported technique" look like "unknown technique".




Conclusion coming from many studies

1. Non adaptation of Intensive systems to municipal capacities (small/medium/big cities):• Higher costs for operations of maintenance of

intensive systems �� from 4 to 18 times (122€/Eq-H) in Yaounde municipal capacity while extensive systems (6 - 35€/Eq-H)

• Persistent of economic crisis �� Non clarification of the financial situation and the perspectives of it long-term increasing which are not either positive



• Challenge �� Find and improve natural systems as alternative solutions which are adapted to a concerned context

Reasons

� Simplicity in study, realization and operation level

� Flexibility and their low costs ��minimizing energy demand �� Less number qualified staff

� Capacity to support strong variations of hydraulic and charge loads

Natural systems as alternative for collective WTP


Reasons

� Relative performance (�� disinfection)

� Lowest land demand lowest in tropical climate zone (rates are 3 times less than in temperate climate),

� Favourable and advantage of climatic parameter under the tropics for photosynthesis of purifier microphytes and macrophytes par example.



Important panel of natural technologies inspired from one natural wetland

� Microphytes/Macrophytes lagoon �� Good treatment but constraints in management

� Floating/Immersed vegetation ponds ��Good clarification but modest tertiary treatment

� Underground manure combined with individual sanitation to complete treatment

� Ligneous plantation treatment �� Still little known

� Sand and gravel filter treatment plant �� Also little known



Perspective stakes

1. Knowledge still remains diffuse/absent

2. Few data are produced in this spécific contexts �� Existing are insufficient despites of efforts of some research institute

Necessity

1. Availability of scientific and technological data (design, mechanisms, valorisation)

2. Understanding and modelling mecanisms Possibilities, Sanitary and environmental risks of coming out products reused in agriculture

Important role of research institute based in Africa: 2iE


� 2iE works on these preoccupations since 20years

Approach

1. Test main natural treatment plants underthe same conditions (climate, wastewater) �

Systematic and objective comparison �Optimization and choose of the "best systems”

2. Finalize new tools of integrated water cycle management into tropical zones

3. Capacity building, Information & Education

Important role of research institute based in Africa: 2iE


� In this context of decentralization ��Municipalities have to adopt solutions for a sustain urban and wastewater management

� Necessity to think about best strategy to finance sanitation and to promote best hygienic practices of reuse out coming products from WTP

� To avoid transposition approach by “simple imitation”, African institute for training and research have an important role and have to be mobilized.

Conclusion

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Title of presentation By Joseph WETHE, PhD Ir., JOSEPH.pdf · 2. Wastewater management in African...

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