Influence of urban wastewater on stream water quality and agriculture in and around Kumasi, Ghana

This paper presents some findings from an ongoing International Water Management Institute research project in Ghana on urban wastewater use in agriculture. The paper focuses on the influence of urban wastewater on stream water quality and peri-urban agriculture in Kumasi, and aims to develop strategies to reduce environmental pollution and risks from agricultural use of wastewater. It drew on interviews with local authorities, sanitation services providers, vegetable producers, traders and consumers, and on an assessment of the existing sanitation infrastructure and water quality. With few industries in Kumasi, urban wastewater is generated mostly from domestic sources. Population increase and lack of investment have overstretched the few available sanitation facilities, and large volumes of untreated or partially treated wastewater end up in nearby streams. High levels of faecal coliform were recorded in the city and downstream, as well as on vegetables in Kumasi's markets, as contaminated wastewater streams are used for irrigation. Although urban and peri-urban agriculture has a positive impact on food supply and livelihoods, it poses health risks for farmers and consumers. The paper discusses the constraints on addressing these problems and makes some recommendations regarding low-cost strategies for safer use of available water, better urban decentralized wastewater management and increased public awareness.