Remediation of Contaminated Urban Streams: A Decentralized Ecological Wastewater Treatment Approach

Abstract

India is going through a period of rapid economic change leading to unplanned urbanization that has impacted the quality of the available water resources in cities and towns. The quality of water in most river stretches within cities and towns fall below category E often rendering river water unfit for any use. These rivers are mostly fed by open storm drains and streams that carry untreated and partially treated sewage and run off from urban and rural landscapes. According to the latest report by Central Pollution Control Board (CPCB), around 50% of the total sewage generated in India flows untreated into various rivers and water bodies. At most places, these water bodies are used as sources for irrigation posing a serious risk to the human health. Given the rapid pace of population growth in cities and the inability of centralized wastewater treatment infrastructure to keep pace with the exponentially increasing wastewater treatment demand, it is important to devise long-term sustainable water treatment and reclamation solutions that can be deployed at a catchment scale. In this context, decentralized in-stream water reclamation technologies present itself as an emerging low-cost, sustainable, and effective solution. These technologies employ ecological processes for the reclamation of a surface water body. In this chapter, we will present (a) a brief overview of the current state of Indian rivers in urban areas, (b) the role of pollution control boards in regulating the surface water quality, and (c) an approach for the deployment of decentralized in-stream treatment technologies for water reclamation.