Rejuvenation of Yamuna water quality by using constructed wetland

River Yamuna is one of the major rivers of the Indo-Gangetic plain. The low perennial flow in Yamuna and the huge quantity of partially treated and untreated effluent it receives, have given it the dubious distinction of being one of the most polluted rivers of the India. Delhi alone contributes more than 3,500 MLD (923.0 MGD) of sewage by virtue of 15 drains out-falling in Yamuna.

In most of the stretch of river Yamuna flowing through Delhi region except for the upstream, water quality falls to E – category, i.e. not fit for any designated purpose. The most critical parameters are BOD, Nutrients, Fecal Coliforms, and Total Coliforms. The gap in the industrial effluent/sewage generated and its treatment is the main cause of the drastic water quality deteriorations. According to a study only 45% of sewage and 55% of industrial effluent are treated up to secondary level. The river is almost dead with no major aquatic life and D.O. The value of BOD and COD is reported as high as 40 and 175 mg/l, respectively. Fecal Coliforms and Total Coliforms were also reported as 989*10⁴ and 1700*10⁴ MPN/100ml.

A dynamic constructed wetland simulation model was specially developed for tropical climate to design different constructed wetlands at the discharge points of six major drain contributing 90% of pollution load on Yamuna.  According to this study, it is envisaged that the proper area and locations of constructed wetlands will definitely make the Yamuna water quality fit for aquatic life and fisheries.