The year-long bioremediation and cleaning project is estimated to cost ₹1.2 crore, officials said, adding that the authority will hire a contractor to ensure daily maintenance and water treatment over the next year.
"The agency will have to ensure biological treatment of lake water, aimed at reducing odour and algal growth and bringing parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), pH, nitrates and phosphates within specified limits. The agency will also be responsible for removing floating plants and waste material like plastic, empty bottles, leaves, branches, polythene bags and religious offerings, using fibre boats," a DDA official said.
It will also be expected to ensure cleaning of grass and vegetation along the lake embankments. Officials added that laboratory tests of water quality will be done every month to monitor improvements at the site.
The Bhalswa landfill adjoining the lake was recently adopted by Union urban development minister Manohar Lal Khattar. At a press conference in September, Khattar announced that he had set a target of clearing the decades-old garbage mound within a year under the "Swachhta hi Sewa" campaign, and said he would visit Bhalswa to review remediation and processing plans.
Khattar added that he had asked DDA and Municipal Corporation of Delhi (MCD) to identify 5-10 acres of land to handle fresh waste so that legacy waste at Bhalswa could be processed without continuous fresh dumping slowing down progress. He noted that biomining at the site began in 2019 following a National Green Tribunal (NGT) order directing that legacy waste at Delhi's three major landfills be cleared within a year, but acknowledged that space constraints, rain, protests and coordination issues had delayed the remediation.
The new lake cleaning project will run parallel to legacy waste clearance at the landfill. Officials said that once awarded, the contractor will be monitored by DDA engineers to ensure continuous dosing, cleaning and testing, with the aim of improving conditions in and around the water body even as landfill remediation continues.