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.