Indirect Potable Reuse of Sewage at Chennai-An Appraisal of Feasibility

Abstract

Necessity is the mother of “invention”. Such was the case in Windhoek, Namibia in 1968 when it faced a grueling water drought. The “invention” was the biologically treated city sewage was reused by blending it with the scarce fresh water and then put through the public water treatment plant for public distribution. This has since been upgraded and water borne epidemics have never been reported. The recent and most talked about is Singapore’s NeWater which mimics the early Windhoek system except that the biologically treated city sewage is further treated by membranes and disinfected with Ultra Violet before a similar blend, water treatment and distribution. Most of the reuse instances in the world are in between these two technology extremes. The necessity of pursuing such an option is looming large at Chennai and this paper explores the feasibility.