Simplified sewerage is an important sanitation option in peri-urban
areas of developing countries, especially as it is often the only
technically feasible solution in these high-density areas. It is a
sanitation technology widely known in Latin America, but it is much less
well known in Africa and Asia. It is the purpose of this Manual to
disseminate this technology more widely in the developing world, so that
it can be used in peri-urban sanitation programmes and project to
improve the health of poor communities. However, simplified sewerage is
not just for peri-urban areas – it can be successfully and appropriately
used in middle-and upper-income areas as well.
Section 1.1 discusses the need for sanitation in periurban areas, and
Section 1.2 introduces the concept of simplified sewerage, especially
its development and dissemination in Brazil. Ideas for promoting
simplified sewerage in countries with no previous experience of the
technology are given in Section 1.3.
The theory of simplified sewerage is presented in the Section 2. Section
2.1 discusses the design value to be used for the wastewater flow, in
particular the design values for the peak factor and the return factor.
Section 2.2. sets out the properties of a circular section, and Section
2.3 gives the Gauckler-Manning equation for the velocity of flow.
Section 2.4 presents the hydraulic design based on minimum tractive
tension; as shown in Section 2.5, this leads to the calculation of the
minimum sewer gradient, and the procedure for calculating the sewer
diameter is given in Section 2.6 The maximum number of households of a
given size and a given water consumption that can be served by a
simplified sewer of given diameter is discussed in Section 2.7. Section
2.8 and Annex II detail simplified sewer design trials using the
Gauckler-Manning, Colebrook White and Escritt equations (which are
described in Annex I).
Section 3 details the planning, management and design aspects of
simplified sewerage. Technical and management options are discussed in
Section 3.1, and sewerage planning in Section 3.2. Design parameters are
considered in Section 3.3, which also details the design of condominial
sewers and that of public collector (or street) sewers.
Section 4 describes the use of the Windows-based computer program
developed for simplified sewer design.
University of Leeds, Leeds, UK, ISBN 0-904280-01-2, 110 pp.