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<International Source Book On Environmentally Sound Technologies
for Wastewater and Stormwater Management>

If wastewater is collected separately, there is no reason why stormwater should be collected in pipes. A recent trend is for stormwater to be channelled through the landscape’s natural drainage, and for the drains to be landscaped to resemble a more natural landscape with vegetation in their flood plain (Figure 1.6). In addition there is the desire to reuse the treated wastewater with its nutrients for purposes such as irrigation of parks and gardens.

Figure 1.6: Separate collection of wastewater for end of pipe treatment, and stormwater allowed to flow through natural waterways and their flood plain. Reuse of treated wastewater for irrigation purposes.

It is worth noting that the severe sanitation problems currently facing many cities in developing countries were experienced in Europe as recently as at the end of the nineteenth century, with epidemics of water borne diseases occurring in London then. The section of river Thames passing through London was grossly polluted until the 1970s. Sewage discharges to the river were treated to reduce BOD concentration and raise DO to enable fish to return. The history of wastewater and stormwater management in Europe is described in greater detail in the Regional Overview for this region.

While the stages of development of sewerage and drainage portrayed above are generalisation of observation in many cities, they are by no means the only way to overcome the problems of sanitation. Various options are described in Section 2 together with their advantages and disadvantages, and a general strategy for selecting the most appropriate option for a particular case suggested.


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