Comparison between conventional and small bore sewerage system for a small township

Abstract

Conventional Sewerage System (CSS) is a traditional system, which is generally used in almost all countries of the world. Conventional Sewerage System(CSS) is costly which is not affordable in low-income countries. In this aspect, small bore sewerage (SBS) system is recently used technology which may be an alternative to CSS in the developing countries. This technology is relatively little known, but it is extensively used in Australia, Africa, and U.S.A. The purpose of this project study was to make a comparison between the CSS and SBS system with a view to examine the suitability of SBS system as an alternative to wastewater management option and it's applicability in small township. Comparison was made of on the basis of technical and economic point of view. Proper design of both the systems and cost analysis of those systems were examined and compared using the data available. The project also represents an analysis of interaction of various parameters, which cause changes of cost in both systems. The study area is the newly developed planned urban area named Lake City Concord in Namapara, Khilkate, in Dhaka. From the cost analysis and graphical representation of CSS and SBS system it can be visualized that in the SBS system cost saving are 28.71% in earth excavation (i.e. only cost difference between the earth excavations of both system), similarly 51.52% in sewer, 48.40% in manholes and cleanouts, and 80.23% in wastewater treatment. Finally, the total capital cost reduction 28.51 % (i.e. grand total cost difference between CSS and SBS system) in the SBS system than the CSS. Also outcome of the study is that in the CSS capital cost per person is Tk 1320.60. Whereas in the SBS system capital cost per person is Tk 1027.65.