Decentralized Wastewater Treatment and Reuse System in Rural India Case Study

Abstract

Abstract. This paper is a case study of the installation and operation of a small bore decentralized municipal wastewater collection and treatment system in a rural Indian village. The completion of the project enabled this village to be cited as the first open defecation free village in Gujarat State. In addition, rather than discharging partially treated wastewater to the environment, the treated effluent from the system will be reused for irrigation of agricultural crops. This case study will discuss several important aspects of the project including: an overview of the site history; the decentralized wastewater collection and treatment system design; a discussion of the process and issues related to certifications and approvals; and the Corporate Social Responsibility funding mechanism. An important aspect of the project was the need to provide the toilet itself as part of the wastewater collection and treatment system. The project is located in a rural village of approximately 50 houses, serving a population of approximately 250 residents. The project was completed early in 2016. The elements of the project include: the toilet, shower and wash basin structure; digester tank; collection network; wastewater treatment bioreactor; and reuse of the effluent discharge. The toilets are standalone structures not connected to the individual homes. In addition to the toilet, the structure includes a hand washing sink, a shower, and a wash basin for washing clothes and dishes. A 500 liter water tank is supported by the structure. The digester tanks receiving the raw wastewater provide anaerobic digestion and settling of the solids so that only solids-free effluent enters the collection network. The collection network is comprised of small bore HDPE piping. The benefit of using fused HDPE piping is that there will be no infiltration/inflow and it is flexible, allowing for an easier installation in an existing site. The wastewater treatment bioreactor is an enhanced vertical flow Continuous Aerobic Multistage Unsaturated System-Soil Bio Technology (CAMUS-SBT) wetland designed, patented and installed by Vision Earthcare (VEC), part of the Business Development Branch of the IIT Bombay University in Mumbai, India. The effluent from the system will be reused for irrigation of local crops. The project was designed in Canada by Clearford Water Systems. The funding was provided by the CSR budget of Infrastructure Leasing & Financial Services (IL&FS) in India. The toilet-shower-wash station concept and design was finalized through collaboration between Clearford and an Indian Architect. The project was completed with all Indian labour and project management. The wastewater treatment bioreactor was designed and installed by Vision Earth Care, part of ITT Bombay University of Mumbai. The Narendra Modi government‘s Swachh Bharat program to eliminate open defecation by 2019 has pushed sanitation to the forefront of national concerns. Corporate Social Responsibility legislation has created a pool of funds available for these sanitation projects.