Water for a food-secure world

FINANCIAL INCENTIVES FOR EXCRETA AND WASTEWATER USEAshley Murray – IWMI-Ghana2nd Ghana Water Forum, Accra 19-21 October 2010

Water for a food-secure worldWater for a food-secure world

Reuse…why bother?Environmental benefits• resource conservation• protect surface waterSocial benefits• decrease public health threat of indiscriminate

discharge

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Financial benefits• help pay for adequate treatment of

*WW/**FS• attract private sector – decrease public

management burden• decrease WW/FS treatment costs

Photo credits: A. Murray

*WW – wastewater**FS – fecal sludge

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“[w]e need to transform the way we look at wastewater, recognizing it as a resource rather than a problem, and manage it accordingly,” (pp 133-134, World Water

Development Report 3 March2009)

TREATMENT PLANTS IN GHANA:• 70 urban treatment plants & ~10 operate effectively • Absence of money for operation and management is a common cause of failure

• Inadequate billing systems• Low household ability and willingness to pay

(Murray and Drechsel 2010)

Photo credits: A. Murray and IWMI

Water for a food-secure worldWater for a food-secure world

DESIGN FOR REUSE: harvesting the value of effluent and nutrients for sustaining the operation of sanitation facilities – IWMI-Ghana & WRCGoals: 1. Improve long-term integrity of WW/FSTPs

in Ghana; 2. Influence shift in status-quo WW/FSTP design

Approach: Demonstrate the benefits of reuse for helping to pay for the costs of WW/FS treatment

Research activities: 1. Cost-benefit analyses and/or demonstration of incorporating aquaculture, irrigation, biogas recovery, land application of FS (dried, composted); 2. Value-chain construction; 3. Implementation & operation protocols; 4. Business model development

Accra, Kumasi, Sekondi-Takoradi

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*WW – wastewater**FSTP– fecal sludge treatment plant

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HYPOTHETICAL CASE: LEGON WASTE STABILIZATION SYSTEM MATURATION PONDSAssumptions:total flow = 6400 m3/d (~81,500 p.e.)maturation pond = 2.1 ha (5-day retention time)stocking density = 3 fish/m2

total fish = 256,000Photo credit: A. Murray

Water for a food-secure worldWater for a food-secure world

WW-fed aquaculture financial-flow model

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fish

Waste Stabilization Ponds (WSP)(e.g. government operated)

privately operated fish farm (in maturation pond(s))

FISH$$

consumers

$

$ for WSP *O&M

operating expenses:e.g. fingerlings, labor

*O&M – operation & managementSource: Created by A. Murray for the purpose of this presentation

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Hypothetical Legon WSP-aquaculture: cost-revenue forecast

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Unit Cost (GH¢) Total Cost (GH¢)

Start-up Costs

Aquaculture equipment (barrels, boots, nets, scale, water quality testing)

1000 1000

Direct Operating Costs

Catfish fingerlings 0.20 each 17,000

Fish feed 0

Site manager/inspector 150/mo 900

Water/fish quality analysis 75 600

Profits

Gross Profit (catfish sales, 75% survival) 3/kg fish 192,000

Net Profit per 6-month cultivation period 172,500

Legon *WSP 6-mo operating cost: GH¢ 86,000

*WSP - Waste Stabilization PondsSource: Created by A. Murray for the purpose of this presentation

Water for a food-secure worldWater for a food-secure world

Wastewater irrigation financial-flow model

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cultivated farmland

Wastewater treatment plant (WWTP)(e.g. WSP, anaerobic/aerobic reactors )

veg.$$

consumers

$

farmers/labor, inputs

$ for *WSP **O&M

POTENTIAL MANAGEMENT MODELSSingle entity owns and operates WWTP and farmland

orWWTP proprietor leases land to private operator

* WSP – waste stabilization pond*O&M – operation & management

Source: Created by A. Murray for the purpose of this presentation

Water for a food-secure worldWater for a food-secure world

WW irrigation: case studyWASTEWATER

TREATMENT SYSTEM

• ~95 m3/d• in disrepair –

little/no treatment

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FARMLAND

• currently rain-fed – no access to *WW

• ~8 ha mixed maize & vegetables

Photo credit: A. Murray Photo credit: A. Murray Photo credit: IWMI

*WW – wastewaterCase study was performed at the Presbyterian Boys Secondary School, Legon, Ghana

Water for a food-secure worldWater for a food-secure world

WW irrigation: case study

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Jan JanFeb

Mar Mar

AprApr

MayJun Jun Jul

AugAug

SepOct Oct

NovDec

Dec0

500

1000

1500

2000

2500

3000

3500

Irrigation Req.(m3/ 10-d.ha) Rainfall (m3/10-d.ha)

wastewater flow (m3/10 day

Temporal irrigation demand vs. Wastewater flow

Profit-max irrigation: ~31,000 m3/yr vs. Wastewater generation: ~35,000 m3/yr

*WW – wastewaterSource: Murray and Buckley (2010)

Water for a food-secure worldWater for a food-secure world

WW irrigation case study: cost-revenue forecast

Unit Cost (GH¢) Total Cost (GH¢)

Direct Operating Costs – Farming

farm labor (16 per year) 100/mo 19,200

inputs (seeds, fertilizer, pesticide)a 400/ha 3200

Profits

Gross Profit (crop sales @ profit-max crop mix)b 44,000

Estimated WWTP O&M costc 5/p.e. 10,500

Net Profit 11,100aBased on input costs reported by farmers in Manya Krobo, Eastern Region (Cofie et al. 2010)bBased on optimization model results using FAO’s CropWat data (adapted from Murray and Ray 2010)cAssumes aerated sequencing batch reactor (current technology) (Von Sperling 2005)

*WW – wastewaterSource: Created by A. Murray for the purpose of this presentation

Water for a food-secure worldWater for a food-secure world

Policy and programming relevance• National Environmental Sanitation

Strategy and Action Plan (NESSAP) 2010– Decentralized Treatment, Reuse and Recovery (DETRR)

Facilities– Private sector engagement

• fully franchised management of all government-built treatment plants by 2015

• Large-scale sanitation projects underway– Accra Sewage Improvement Project (AfDB –

Africa Development Bank)– Urban Environmental Sanitation Project (WB –

World Bank)

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Water for a food-secure worldWater for a food-secure world

So, next time… Don’t think of wastewater.

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Water for a food-secure worldWater for a food-secure world

Relevant publications• Murray, A. and P. Drechsel (2011). "Why do some wastewater treatment facilities

work when the majority fail?" Waterlines (in press).• Murray, A. (2010). Demanding reuse at wastewater treatment plants: A case of the

private sector helping to pay for sanitation. World Water Week, Stockholm. Available at: www.worldwaterweek.org/.../Ashley_Murray_WWW_2010_pres.pdf.

• Murray, A. and C. Buckley (2010). Designing Reuse-Oriented Sanitation Infrastructure: The Design for Service Planning Approach. Wastewater Irrigation and Health: Assessing and Mitigating Risk in Low-Income Countries. P. Drechsel, M. Redwood, L. Rachsid-Sally and A. Bahri. London, Earthscan, IDRC, IWMI: 303.

• Murray, A. and I. Ray (2010). "Back-End Users: The Unrecognized Stakeholders in Demand-Driven Sanitation." Journal of Planning Education and Research 30(1): 94-102.

• Murray, A. and I. Ray (2010). "Wastewater for agriculture: A reuse-oriented planning model and its application in peri-urban China." Water Research 44(5): 1667-1679.

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