Water supply adaptation for changing water sources: introduction to movable water treatment plant

Abstract

Climate change has significant impacts on water resources and particularly has detrimental impacts on water supply and management of water sources. Although Sri Lanka has a tropical climate with little seasonal variation, Sri Lankan climate has experienced vast changes in the last few decades. Due to these changes, it is really difficult task to find a reliable and long term water sources for supplying drinking water to the people who are living in isolated areas. On the other hand, the changes of river basin characteristics due to urbanization and industrialization are aggravating this problem. Increasing demand for treatment facilities of surface water due to above reasons and lack of funds to implement enhanced water treatment facilities are the major problems encountered at present. The concept of a locally made movable type surface water treatment plant emerged with the objectives, to be maintained the drinking water quality standards due to changing the raw water quality of water sources and facing disaster situations as floods, tsunami or earthquake. There is a rising demand for cheaper, easy to build, movable type water treatment unit operation modules which are an effort to reintroduce conventional water treatment modules using low cost construction materials and prefabrication techniques to achieve less construction time and movability of the modules.This study explains an approach to achieve these goals at affordable and sustainable manner. Prime objectives of this project is to create a water treatment plant of shorter construction period, affordable capital investment, capability of moving the plant to different locations when needed and to be a viable in 500 to 1000 m3day capacity in range. The introduced movable water treatment system basically includes three modules; tube settler, chlorine contact tanks and rapid sand filter. As a pilot project, these modules have been integrated at two main water supply schemes in Sri Lanka at Pugoda and Mahiyangana. Detailed assessment has been carried out to test the performance of the system as well as an economical assessment have been carried out. The assessment output highlights the suitability and high performances of the introduced systems. Output of this study will assist water resources managers and decision makers to face the future challenges related to impacts of climate change on water resources and drink water supply.