The first centralized sewage collection system in Addis Ababa was established in the 1960s and was designed for the collection and conveyance of wastewater to a treatment plant located in Kaliti. With a capacity of 7 500 m3

/day, the Kaliti system was

designed to serve only 200 000 inhabitants. When operating at full capacity, the wastewater treatment plant serves less than 10 per cent of the residential areas connected to the system (EPA 2005). The second wastewater treatment plant was established at Kotebe, and has a capacity of 30 000 m3

/day (EPA 2005), enough

to serve 800 000 residents. The homes that are not connected to the wastewater treatment plant dispose waste into the city’s storm-water drainage system (van Rooijen and Taddesse 2009).

WATER POLLUTION

The seasonal and perennial rivers and groundwater reserves of Addis Ababa are polluted by industrial and municipal solid and liquid wastes. The polluted river water is used by downstream residents to grow vegetables, which are sold and consumed by inhabitants of the city.

The city’s rivers are contaminated with different organic and inorganic pollutants. The shallow groundwater and springs are also contaminated (Tale 2000, Alemayehu and others 2005, EPA 2005).

Solid waste that is generated is often disposed of in open spaces, where it is washed by runoff during rains, and flows into rivers and seeps into shallow groundwater.

INDUSTRIAL WASTE

There are more than 2 500 industries in Addis Ababa, 90 per cent of which lack onsite treatment facilities (AAEPA 2007, unpublished report in Gebre and van Rooijen, 2009). These industries discharge waste into nearby stream courses and open ditches and the Akaki River is heavily polluted. A 1999 report estimated the volume of wastewater discharged from industries into the rivers at 4.8 million m3

(Central Statistics Authority 1999). MUNICIPAL WASTE

Despite generating large amounts of solid waste from domestic activities, Addis Ababa does not have adequate waste management facilities. As a result solid waste is often piled on available open grounds, stream banks, and near bridges, where it is washed off into rivers. According to SBPDA (2003), 65 per

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