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to the discharge of WC wastes to open drains. The dimensions of these are typically similar to those at Thirukatchur. |
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Observation of the operation of household septic tanks discharging to open drains, which are not normally fitted with a sanitary tee on the outlet, reveals that finely divided solids are washed out every time a flush of water enters a tank. Bearing in mind the fact that the main purpose of interceptor tanks is to remove gross solids rather than to provide treatment, it is arguable that sanitary tees should be omitted from them, allowing material from the floating crust in the tank to be washed into the sewer and thus reducing the rate of sludge accumulation. The material flushed out should not cause problems in sewers because of its low-specific gravity and finely divided nature. |
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It is commonly assumed that the failure of householders to make connections to sewers is a significant problem in low-income areas. This was perceived to be a potential problem in North East Lahore where there was little community involvement in either planning or implementation and government efforts did not extend beyond plot boundaries. In order to minimize future disruption, it was decided that existing open drains along the sides of lanes should be covered and in effect converted into shared connections. This system did not work well for two reasons: first, because householders continued to view the connections as drains and they did not worry if gaps appeared in the cover slab for any reason, and secondly because no one took responsibility for maintaining the side drains. The water authorities said, rightly, that the drains were not sewers; the municipal authorities said that they were only equipped to clean open drains; and the householders were reluctant to take responsibility for a shared facility which they had not requested. Subsequently, experiments were made with replacing the covered drain arrangement with 100 and 150 mm pipes and these appeared to work better. However, in principle, it seems better to make connections from individual houses to a sewer wherever possible. |
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A more positive approach to the connection problem is to recognize that the problem is likely to disappear if residents are involved in the planning and implementation process for local |
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