Chapter 5 - Application of constructed wetland; a natural treatment system for environmentally sustainable domestic sewage treatment

Abstract

Water resources throughout the world are severely threatened from different pollutants released into water bodies, thereby causing water pollution. Sewage is wastewater released by household drains, residential apartments, communities living in urban agglomerations, and contains of human fecal matter and large volume of water. Chemically, it contains suspended and dissolved solids (TSS and TDS), dissolved organics, nutrients (nitrate, ammonia, and phosphorus), minerals, and pathogens (bacteria, protozoans, viruses, helminth eggs), gases like H2S, CO2, CH4, and NH3, etc. Almost all the sewage ultimately finds its way to the aquatic ecosystems and is a major source of water pollution. There are several wastewater treatment technologies; however, Constructed Wetlands (CW) have emerged as an eco-friendly, economically viable option for sustainable treatment of sewage. CWs are manmade or engineered wetlands that are designed built and operated to harness the functions of natural wetlands for the treatment of various pollutants from wastewater. Constructed wetland is a well-known technology in the different parts of the world especially in European countries for the treatment of domestic sewage. But, in Indian context such studies are very limited and this technology can be applied to even the remote areas of the country where capital and energy inputs are the major issues related to sewage treatment. Under present chapter, we have reviewed some important studies conducted worldwide dealing with application of CWs for the treatment of the sewage. We have also reviewed such studies conducted in Indian context. Our study suggests that the CWs are a natural technology of wastewater treatment and it had been a successful technology in the Europe; however, its use has been very limited in India context and more studies can establish this technology as a viable option for sewage treatment in Indian context.