Fate of Nutrients in Human Dominated Ecosystems
Jakkur lake, wastewater, sewage treatment, nutrient flux, mass balance.
Jakkur Lake in the city of Bengaluru covers an approximatearea of 55 hectares and primarily receives inflows from theJakkur sewage treatment plant (STP) and an open storm drain.Jakkur STP discharges an average of 10 million litres of treatedwater daily (MLD) into the lake. The open drain dischargesabout 0.5 MLD of raw sewage into the lake. In the absence ofenvironmental flows it becomes critical to assess the impact ofnutrient flux on the quality of water, and design cost effectivetreatment solutions to address the issues of lake water quality.As part of this study, we have assessed the impact of thesetwo primary inflows on the overall water quality of JakkurLake. The results have shown that nutrient inflows have led tothe increase of chlorophyll-a levels, eventually causing hypereutrophicationof Jakkur lake. We have also used simplemassbalance approach to assess the contributions of in-lake activities(sedimentation and reaction) on removal of nutrientsfrom the lake. We have concluded that the phosphorus loadhas to be reduced by approximately 96% from the currentlevels to prevent algal blooms within Jakkur Lake.