Abstract:

Almost half of the world's lakes are degraded, depleted, and contaminated mainly by human activities. The main causes are inflow of domestic sewage, agricultural run-off, discharge of industrial effluents, over-fishing, introduction of exotic species and habitat degradation from population growth, expansion of cities. As more water is withdrawn for human use and more of it is returned to lakes and rivers badly polluted there is less available to maintain vital freshwater ecosystems. Major degrading factors include excessive eutrophication due to nutrients and organic matter loading from domestic wastewater. Thus, it is necessary to take a step for management and restoration of lakes. Looking for a problem, a pilot scale study based on phyto-treatment concept was setup in National Environmental Engineering Research Institute (NEERI) laboratory, Mumbai. Treatment efficiency of subsurface design ecosystem were evaluated for pollutant parameters such as total suspended solids (TSS), biochemical oxygen demand (BOD), nitrogen (N), phosphorus (P) and fecal coliform (FC). The results indicate high removal efficiencies particularly for BOD, TSS and FC. Wetland bed was prepared with locally available plants such as bulrush and cattails. This technology offers several advantages such as simple operation, maintenance, economically and environmentally sound treatment of wastewater as well as for aquatic habitants.