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problems of part of the area. There were also some difficulties in getting the Water and Sanitation Agency to provide the resources to operate the temporary pumping station and this illustrates the problems which are inherent in projects which are made the responsibility of specially formed 'upgrading units' rather than the appropriate line agency. In Faisalabad, three of the four pilot areas are served by collector sewers but these all have limited capacity and discharge to pumping stations from which they are lifted into open channels without any treatment. These situations illustrate the point that off-site facilities must be fully considered when sewers are provided in an area. Where such facilities are not available, as will often be the case, other options such as sewered interceptor tank systems which may be connected to existing drains will have to be considered. |
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In cities such as Lahore, Faisalabad and Madras, the topography is such that sewage discharged into conventional systems has to be pumped at least once in the course of disposal. Pumping uses energy and therefore requires financial resources which are usually in short supply. Sewage pumping stations in Lahore and Faisalabad do not operate 24 hours a day. In Lahore, pumping is often discontinued overnight and in both cities there are frequent periods of electrical 'load shedding' during which there is no power for the pumps. Many of the pumping stations in Faisalabad are poorly laid out and are in such a very poor state of repair that they must break down frequently. Observation suggests that operators frequently run pumping stations with the wet-well liquid level above the soffit of the incoming sewer as a matter of routine. The result is that the incoming sewers are surcharged, so that design assumptions on flow velocities are not realized. It would be surprising if this pattern of operation were not to be found throughout the subcontinent. One result of this is that settlement is likely to occur in main sewers, reducing their capacity in the short term and their working life in the longer term. This adds to the problems which most rapidly developing cities face with the lack of capacity and the limited extent of existing systems. |
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There is often a large gap between the long-term objectives of ambitious sewerage master plans and the immediate needs of local communities. For instance, none of the four pilot areas in Faisalabad will be affected by current investment in sewerage and sewage treatment until further investments are made in trunk |
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