Waste dumps releasing toxic fluids

Study shows high leachate levels remain untreated

The haphazard dumping of garbage at various landfills outside the City has taken a toll on the health of residents in surrounding villages.

Leachate, a toxic fluid which is often discharged from decomposing urban organic waste has been responsible for the contamination of both groundwater and surface water in areas around the dumping grounds.

Leachate which is formed when water passes through the waste deposit, poses major challenges in waste disposal. With little knowledge on handling leachate and owing to the sheer negligence of the local authority, no tests were conducted before the landfills were opened. In addition, no measures were taken to treat leachate.

A study conducted by Pratibha D’Souza, a research scholar, and Dr R K Somashekhar,  chairperson of the Department of Environmental Science at Bangalore University, showed that leachate samples from solid waste dump sites at Nyanappanahalli, Kumbalgod, Mandur, Mavallipura and the Karnataka Compost Development Corporation all contained  high levels of pollutants. The samples collected for study have exceeded the safety standards.

On the scale of the leachate pollution index, in which a level of 7.4 is regarded as acceptable, tests at the landfills showed levels of 19.79 during the pre-monsoon season and 14.46 during the post-monsoon season.

At Nyanappanahalli, the quarry always held rain water and no care had been taken to drain it. At Mavallipura, solid waste is disposed of by aerobic composting and landfilling.
There is a water body two km away. In Kumbalgod, leachate from the waste drains into the nearby Subrappanapalya Lake, which has become a leachate collection pond. The Karnataka Compost Development Corporation, which is an abandoned composting unit, has stopped receiving waste since 2008. But untreated leachate from the site continues to seep into wells near Haralakunte Lake.

In a survey of 409 residents in 16 villages, in the vicinity of Kumbalgod, Mavallipura, TerraFirma and Mandur dumping sites, respondents said that they had suffered socially and psychologically because of the proximity of their houses to the dumping yards. Many also claimed that they had developed health problems. “Depression seems to be the most common problem among villagers as they said that their relatives had stopped visiting them,” said D’Souza. “Many people suffer from skin allergies and one has to travel for nearly two km to visit the nearest doctor.”

The study recommends that site-specific leachate treatment plants based on the characteristics of waste, leachate composition and concentration, should be made mandatory at all solid waste disposal sites.