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problem by the operators of the pumping stations, and the municipal engineer appears not to have highlighted it as such. As the third pumping station, which mainly serves the industrial catchment, does not operate due to theft and vandalism, the flow is discharged directly into a local water course, where approximately 75 per cent of the combined flow is raw sewage. This water course passes through agricultural and residential areas and so poses a severe threat to local public health. As this sewage may also contain heavy metals and toxic chemicals, it is unquantifiable what long-term effects this may have on the population, either directly or via the groundwater, which serves as a source of potable supply. |
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The rising mains that emerge from the three pumping stations are designed to pass for about 1 km under pressure, before the effluent flows under gravity, via a grit collection chamber, to a short sea outfall. However, the three pipes are badly corroded in parts, and sewage escapes into the environment. There has been no money in the past for the rehabilitation of these mains, leading to rapid deterioration. Often small-scale crops are grown alongside these water courses, with irrigation water provided directly from them. It is a cause for concern that the majority of these crops, such as lettuce and other salad crops, will carry pathogens directly to the consumers of these products. |
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A grit collection chamber, which had become disused over the last 10 years, because of the problems with the pumping stations and the rising main previously discussed, was rehabilitated in early 1995, when approximately 200 m3 of solids were removed. It is an open chamber, constructed from mass concrete to a Soviet design, and is approximately 20 m wide by 35 m long, and about 3 m from ground level to invert level. It contains a dry weather flow channel, and a crude concrete flow attenuation device at the downstream end. It is difficult to conceive that this channel could ever operate effectively, due to its inherent bad design, and given the lack of operation and maintenance culture within the municipal assembly and the local development corporation. |
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Flow should pass through the grit channel to be discharged at sea via a short sea outfall. However, this outfall is now fractured in a number of places, resulting in premature disposal close to the shore and hence inadequate dispersion. The fractures were caused by the practice of illegal wrecking of unwanted ships |
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