African Water Development Report 2006 - United Nations Economic ...

The problem of wastewater disposal is as importantas that of water supply in many urbanareas. The discarding of wastewater and other refusefrom large urban centres in both developedand developing states has a negative impact on awider range of ecosystems. Aquatic ecosystems,from where urban areas obtain their water, eitherdirectly or indirectly, have severe impacts on thesupply of water to urban populations.the increasing use of fertilisers in African countriesin the period 1999-2001.These areas sometimes also have the lowest grossnational product (GNP), which is a limiting factoron capital needed for wastewater treatment.Wastewater can be handled in a number of ways:Treatment measures from developed States canbe applied by developing countries. It can alsobe recycled for reuse in urban areas, as is theFigure 4.19: Dynamics of African Population Growth by SubregionFRESHWATER RESOURCES IN AFRICA2003 2025 2050Mid-Year Population700 000600 000500 000400 000300 000200 000100 0000Eastern Africa Middle Africa Northern Africa Southern Africa Western AfricaSub RegionSource: World Population Prospects: The 2002 Revision. New York: UN Secretariat, 2003Not only do they raise the cost of purification, butwaterborne diseases may also threaten the healthof those who live near water sources in urban areas.These people usually live in shantytowns inlarge cities in developing States, and quite closeto rivers and streams from which they draw theirdaily water. It is not uncommon to hear abouta cholera outbreak on the periphery of cities indeveloping states, where most of these townshipsare located. This occurred in 2001, in Alexandra, atownship near the Johannesburg City Center (R.Meissner, 2002). Wastewater creates the greatestproblem where the population of an urban areagrows most rapidly, particularly in the developingworld. One of the sources of pollution is thewashing of fertiliser residues from agriculturalproduction into water bodies. Figure 4.20 showscase in Windhoek, the capital city of Namibia,which has been recycling wastewater for urbanuse since the mid-1960s. Wastewater can also bepartially treated and used in the agricultural (Israel)and industrial sectors (ibid). The interrelationshipbetween population growth and globaland regional water resources is of such a naturethat demography does not only affect the quantityof water but also on its quality. The morepeople there are the less the water available perperson. There might even be less freshwater infuture if policies and initiatives are not proposedand implemented to address the matter of pollutionwithin the context of global and regionalwater resources even though the present levels ofchemical pollution are still low (fig.4.20).77