4.1.4 Stormwater

Although not a form of liquid waste in the same way as wastes from residential, commercial and industrial areas, stormwater is also a form of wastewater. Stormwater can be contaminated with many different types of pollutant such as faecal matter, soil, rubber from vehicle tyre wear, litter, and oil from vehicles. Many parts of Ethiopia are faced with large volumes of stormwater during the rainy season (Figure 4.4). Where there is a sewerage network (a system of sewers), stormwater may be channelled into the sewers, or it may flow into open ditches.

Figure 4.4 Stormwater flow during the rainy season in Ethiopia can sometimes exceed the capacity of the drains.

4.1.3 Liquid wastes from industrial areas

4.2 Characteristics of liquid wastes