Wastewater treatment capacity, food production and health risk in peri-urban areas: a comparison of three cities

Growing cities and their demand for water challenges the management of water resources and provides opportunities for wastewater use in irrigated agriculture. In the cases studied, large volumes of fresh water are extracted from sources often located increasingly further away from the city, while investments in wastewater disposal often lag behind. The resulting environmental impact in peri-urban areas can have multiple consequences for public health, in particular through the use of untreated or poorly treated wastewater in irrigated agriculture. Despite significant efforts to increase wastewater treatment, substantial volumes of untreated wastewater are applied in irrigated agriculture in Addis Ababa (Ethiopia), Accra (Ghana) and Hyderabad (India). Additional options for safeguarding public health are required to allow the cities to maintain the benefits from already existing, but largely informal, wastewater reuse.