A review on decentralized wastewater treatment systems in India.

Pollution of water resources and a lack of potable water are two important issues that city dwellers in India encounter. The passage of untreated sewage down municipal drains is one of the most significant sources of water resource pollution. In densely populated areas, effective sanitation and wastewater management is becoming increasingly difficult. In many developing nations, centralized sewage and wastewater treatment facilities serve only a section of big cities, and on-site sanitation is frequently insufficient in heavily populated areas. There is a demand for complementary and intermediate solutions. DEWATS (community-managed anaerobic decentralized wastewater treatment systems) is a good option for the possibility of relatively fast sanitation improvements in high-priority neighbourhoods where the local authority is not providing a full sanitation service. The following technical treatment modules are typically seen in DEWATS. The primary treatment consists of sedimentation ponds, settlers, septic tanks or bio digester, secondary treatment consists of anaerobic baffled reactors, anaerobic filters or anaerobic and facultative pond systems, secondary aerobic/facultative treatment consists of horizontal gravel filters and post-treatment consists of aerobic polishing ponds. The experience of India in establishing community-managed DEWATS on a large scale is examined in this review. [Display omitted] • DEWATS have been implemented in different places with suitable treatment methods matching with the community needs. • DEWATS which are connected to communal sanitation centres have the ability to bridge the gap between on-site and centralized wastewater treatment systems. • Very little data is available about the practice of DEWATS other than the handbooks available by different DEWATS implementation agencies. • This paper gives a review on the different DEWATS methods adopted in India which will impart a knowledge on the selection and implementation of different unitary process to be adopted for DEWATS process. [ABSTRACT FROM AUTHOR]