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sewerage. Provision for these investments is included in plans for the next century, but experience to date suggests that financial constraints are likely to lead to considerable delays in the implementation programme. There are no easy solutions to this situation. In theory, there is an argument for decentralizing systems as much as possible so as to reduce the length of trunk sewers. At one extreme, the Yusufabad and Thirukatchur schemes are completely independent of centralized systems. In Yusufabad, some treatment is provided in a series of septic tanks, each receiving the effluent from 60 to 80 houses but a better approach might have been to buy sufficient land for a waste stabilization pond system. Provision for local treatment is provided in several of the TNUDP sites-and-services schemes. |
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There are two potential problems with this approach, the first that of obtaining the land necessary for treatment and the second of ensuring that local treatment facilities are operated and maintained. The first is a real issue in Pakistan because of the high price of land around large cities. Land prices around Yusufabad are currently about Rs300 (US$10) per m2, and prices around cities like Lahore are higher. Both governments and community groups are likely to be reluctant to spend scarce resources on land for treatment, given that the provision of sewerage solves the local environmental problems which most concern people. At Yusufabad, the possibility of combining waste stabilization pond treatment of the effluent from septic tanks with fish farming was considered and a scheme was prepared but it was eventually decided that the residents of the settlement were insufficiently well motivated to undertake the management of the fish farming scheme. |
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The discussion above assumes that waste stabilization ponds are the appropriate treatment technology for disposal of sewage at the local level. There is considerable evidence that the operation of conventional treatment works is often less than satisfactory because of poor operation and maintenance and it would seem extremely doubtful whether conventional technology can be introduced at the local level. However, while inadequate operation and maintenance often contribute to poor performance, there is another factor which is often overlooked and which potentially applies to waste stabilization systems as well as conventional treatment works. This is the tendency for facilities to become overloaded because investment levels are insuffi- |
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