Recycling of Urban Organic Waste for Urban Agriculture
A D V E R T I S E M E N T
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The Urban Waste Challenge
Municipal authorities have insufficient financial, technical, and institutional capacities to collect, transport, and safely treat and dispose of municipal wastes, consequently waste management remains one of the major urban problems (Drechsel and Kunze, 2001).
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In Ghana for example, 58 percent of the solid waste (SW) generated is dumped by households in designated dumping sites, 25 percent is dumped elsewhere in non-designated sites, and only 5 percent is actually collected. The quantity uncollected varies from place to place and could be as high as 20 percent as in the two largest cities of Accra and Kumasi. (GSS, 2000).
The situation in other African cities is hardly different. In many cities household waste collection is restricted to wealthy neighbourhoods, while in the remaining areas waste is dumped along road sides, in illegal dumps and in storm water drains (Mbuyi, 1989).
The city authorities in Tanzania collect only 24 percent of the refuse (Kulaba, 1989) while in Nigeria, 35 percent of Ibadan's households, 33 percent of Kaduna's, and 44 percent of Enugu's do not have access to waste collection. (Asomani-Boateng and Haight).
In Ougadougou, Burkina Faso, about 23 percent of household wastes are deposited in small drains (Ousseynou, 2000). In India, about 50 percent of the refuse generated is collected. As much as 90 percent of the Municipal Solid Waste (MSW) collected in Asian cities end up in open dumps. (Medina, 2002). The failure of city authorities to collect waste leads to unpleasant conditions and decomposing wastes constitute a serious health and environmental hazard (Ali, 2004).
The volume and composition may however be subject to large seasonal variations (GFA-Umwelt, 1999). A detailed report on the organic waste flow in integrated sustainable waste management has been written by Dulac (2001). In short, the waste stream is not a homogenous mass but a collection of different materials (organic material, plastics, metal, textiles etc.) that can be handled in different ways to maximise recovery. The organic waste fraction remains the largest proportion to be recovered.