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The International Conference on Low-Cost Sewerage was held at Weetwood Hall, University of Leeds, during 1921 July 1995. Delegates attended from Colombia, Finland, Greece, India, Malaysia, Nigeria, Pakistan, South Africa, the United Kingdom, the United States, Venezuela and Zimbabwe. Fourteen papers were presented which, together with the Conference Conclusions, make up the 15 chapters of this book. |
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Low-cost sewerage is probably the only sanitation technology that is applicable in the high-density, low-income urban and periurban areas of developing countries. Often this will be simplified sewerage, especially its in-block variant now generally called condominial sewerage, although settled sewerage (which used to be called small-bore sewerage) may also be appropriate, particularly in areas already served by septic tanks. On-plot water supplies are commonly thought of as being a prerequisite for low-cost sewerage, but they are not essential: simplified sewerage worked well in a very poor slum area of Karachi which was served only by public standpipes. |
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Settled sewerage schemes were first installed in the late 1950s in what is now Zambia, and its inflective gradient design approach (which correctly ignores self-cleansing velocities) was developed in the United States in the mid-1970s. Simplified sewerage was a later development: condominial sewerage was first installed in low-income housing areas in Natal, northeast Brazil in the early 1980s, and it is now becoming quite common elsewhere in Brazil and the rest of Latin America. |
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Dissemination of the current state of knowledge about lowcost sewerage is extremely important if its literally vital message is to reach practising engineers in developing countries. The 1985 World Bank TAG Technical Note on small-bore sewerage and the 1986 UNCHS Manual on shallow (i.e. simplified) sewerage were a start. In 1994 the UNDP-World Bank Water and Sanitation Program produced design guidelines for simplified sewerage |
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