This paper by Ajit Seshadri, Vigyan Vijay Foundation highlights the poor sanitation situation in India and argues that centralized approaches to wastewater treatment have had limited success and there is a need to make wastwater treatment people centric and effective through the use of decentralized systems such as DEWATS (Decentralized Wastewater Treatment Systems). DEWATS are locally organized and people driven systems that typically comprise a settler, anaerobic baffled tanks, filter beds of gravel and sand, and an open pond. The open pond or the polishing tank recreates a living environment for the wastewater to clean itself, naturally.The system operates without mechanical means and sewage flows by gravity through the different components of the system. Up to 1, 000 cubic metre of domestic and nontoxic industrial sewage can be treated by this system. DEWATS applications provide state of the art technology at affordable prices because all of the materials used for construction are locally available. DEWATS approach is an effective, efficient and affordable wastewater treatment solution for not only small and medium sized enterprises (SME) but also for the unserved (rural and urban) households in developing countries, especially South Asia
In India, domestic wastewater, including sewage that is often not even collected, is a major source of pollution of surface water. This contributes to contamination of groundwater an important or only source of drinking water for many urban and peri urban areas. In addition, the economies of scale required for using conventional technologies would not be achieved in all settlements for various reasons, including: i) different climatic conditions; ii) topography; iii) geological conditions and water tables; iv) levels of urbanization; and v) population densities and size of settlements.
The paper argues that decentralized and low cost wastewater treatment and waste management can provide more appropriate solutions in several situations, in the context of India. A significant opportunity available in India is to introduce decentralized systems through which the resources generated from the wastewater, including recycled water and manure etc., can be utilized locally at much lower costs.
The paper goes on to describe the innovative approaches undertaken in Delhi for wastewater management by describing the projects implemented by Vigyan Vijay Foundation, an NGO in Delhi for management of wastewater. The paper ends by arguing that given the urban sanitation situation in India,
- There is a need to promote decentralized initiatives in waste water treatment by providing incentives and a supporting policy environment and through capacity building of implementing institutions.
- There is a need to support implementation of pilots and projects, which demonstrate not only the decentralized and lowcost treatment of wastewater, but also how communities and local administration can partner to implement the interventions in ways that make the facilities more durable and long lasting.
- There is a need for exchange of information and innovations amongst developing countries, and technical support for introducing alternative technologies and processes
A copy of the paper and another initiative by Vigyan Vijay Foundation of using recycled water applying natural treatment for horticulture from wastewater and the paper presented by Ajit Sheshadri, Vigyan Vijay Foundation, Securing Access to Quality Perennial Re-use Water through Wastewater Recycling for Urban Landscaping (pg 241-242) at the World Water Week in Stockholm, August 16–22, 2009 can be downloaded from below: