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Research says unscientific dumping of waste is affecting Bengaluru’s lakes and wells

Photo: Dennis C J

“There is no such thing as ‘away’. When we throw something, it must go somewhere”, said Annie Leonard, a famous critic of consumerism. But what happens around “somewhere” when we throw out our wastes? A recent study by a team of researchers at the Indian Institute of Science, Bengaluru, has analyzed the composition of the water that passes through landfills and has dissolved and suspended matter from it, called leachate, from the infamous Mavallipura landfill and has examined its effects on the nearby lakes and wells. Prof. T. V. Ramachandra from the Centre for infrastructure, Sustainable Transportation and Urban Planning (CiSTUP) and his team have also highlighted the resulting ill effects and suggested some steps to minimize the same.

A big fraction of the waste from households, hotels and offices in Bengaluru goes to the Mavallipura landfill site, about 20 km from the city. This dumping site has been receiving the city waste since 2005, and is often in news due to the frequent instances of vector borne diseases, air and water contamination and impacts on people’s livelihood leading to frequent protests against the same. The landfill receives upto 600 tonnes of waste per day out of which 70% is biodegradable. Contamination of soil, release of harmful gases, vegetation damage and unpleasant odors are some of the ordeals the residents face. Another major problem from this 35 acre area is the toxic landfill leachate polluting the water bodies and groundwater resources.

This landfill leachate is a concentrated mix of ammonium, nitrogen, hydrogen sulfide, heavy metals and other organic contaminants. The characteristics of the leachate depend on the materials in the waste, the climatic conditions of the region and the moisture content in the soil. More the organic content in the waste, higher is leachate’s impact on surrounding land and water bodies. This study attempts to characterize the leachate through chemical and biological analysis and understand its harmful effects on the environment.

During the study, the researchers collected several samples from the drainage area and nearby lakes and wells. These samples were examined using methods like electron microscopy and X-ray analysis for elemental composition. Apart from these, other chemical tests were carried out. They found that these samples had high content of chloride, sodium, potassium and heavy metals, which are highly toxic to all living organisms including human beings, which if gets into food chain and can affect vital organs (kidney, liver, etc.). Unique bacterial assemblages dominated the leachate samples, indicating likely serious health implications. “Our studies have shown algal bloom in the nearby lakes and contaminated groundwater in the vicinity of 1 km. This is mainly due to leaching of contaminants from the waste”, says Prof. Ramachandra. This is worsened in the monsoon months when huge amounts of water runs through the landfill and eventually drains into the water bodies in the vicinity.

This emphasizes that due to mismanagement of city waste the water around the landfill is unfit for drinking, and also unsuitable for any kind of domestic use. Unauthorized practice of dumping biodegradable waste mixed with recyclables is rampant in most Indian cities despite Government of India’s stringent rule on Solid Waste Management. The landfill site is in close proximity to human habitations and consequent pollution has been posing serious threat to the society.

The study has suggested some steps to minimize these negative impacts on the natural environment and to rejuvenate the landfill. A systematic waste separation system will not only improve the poor condition of the landfill but also open employment opportunities for the locals through recycling and ‘waste to energy’ generation. The study also suggests that collection and subsequent treatment of the leachate through bioremediation would help in reducing the contaminants. “These steps can significantly improve the conditions in any landfill site and also help in decontamination within 18 months”, asserts the research team.