The legacy dump in the Jawaharnagar solid waste management facility could finally cease to be an issue, thanks to near completion of capping works.
The concessionaire agency is working on development of green cover which is the outermost layer of the capping, officials informed. More than half of the green cover too is complete, and dibbling is going on to ensure the grass kicks the roots inside. Once it is done, rain water seepage into the trash hillock will stop altogether. Soil cover of 300 millimetres thickness on the enormous trash pile has been followed by a geosynthetic clay liner, a flexible HDPE membrane layer and a geo-drainage layer. Final topping was of restoration soil on which vegetation is being grown.
“The project is in its end stage, with 95% of the work finished. Lines have been formed on the surface for drainage of rain water, which will join the main garland drain. It will carry the water away from the site,” informed Rahul Raj, Additional Commissioner (Sanitation), GHMC.
Leachate will however, continue to be a problem till such a time that it is completely treated and disposed of. As of now, over 600 million litres of leachate exist in nine artificially created ponds, which, when mixed with rain water, increase in quantity and poses a challenge to the authorities, by flowing into the lakes nearby.
Two treatment plants each of two million liters capacity per day exist at the site, to treat the leachate presently. Earlier, the leachate sludge after treatment would be redirected into the ponds. Mixed with rain water and the fresh leachate oozing from the dump, it would increase in quantity.
“We have now ensured that fresh ponds with lining are created to deposit the sludge after treatment. With rainwater collected and carried away, the ponds will have no addition except the direct rain received by them. We are also calling for global tenders to treat the leachate within definitive period of time. They will have to create Multi Effect Evaporator Plants to convert the sludge into powdery form,” Mr. Rahul Raj said.
Capping of the legacy dump—the 70-80 metre high hillock of 12 million tonnes of trash profiled into a hillock by the concessionaire agency-- has been going on for painfully long period. The ₹ 140 crore project was taken up after several complaints and vociferous protests by the people of 30 villages and colonies surrounding the location, who had been enduring unbearable stench and polluted ground and surface water for years.
Officials have informed that the Malkaram Lake water has been treated, and no more leachate is being left into the lake. Meanwhile, the GHMC is filing a review petition in the National Green Tribunal, which had directed the government to reduce the legacy dump through bio-mining. Government is contending that bio-mining at this stage is not an option as it would release intolerable stench, which would be objected by local residents.
