What happens to old quarry pits like those in Mavallipura, Mandur, Mittaganahalli and Bagalur that the Bruhat Bengaluru Mahanagara Palike (BBMP) used to dump several hundred tonnes of waste generated by the city?
Though the civic body has stopped sending waste to these sites, the waste accumulated over the years remains a major pollutant, much to the chagrin of the communities living around them.
After several haphazard and failed attempts at bio-remediation where micro-organisms are used to neutralise or remove contamination from waste, the BBMP is taking another shot at an eco-friendly process in its attempt to address the problem. This time, officials claim, they will go about it in a planned manner, and will be funding a project to study and develop methodologies to reclaim old landfills.
The project proposal — submitted by the Centre for Sustainable Technology, Indian Institute of Science — was scrutinised by the BBMP’s Technical Guidance Committee in April 2019. The committee recommended that the proposal by researchers G.L. Sivakumar Babu and H.N. Chanakya is relevant to the needs of the civic body. The title of the proposal is ‘Development of methodologies for rehabilitation of municipal solid waste dumpsites’
“Through the project, we hope to develop guidelines and methods for remediation of dumpsites, mitigate greenhouse gas emissions, besides develop technology for leachate treatment,” said Dr. Babu.
Study site
Senior civic officials said the BBMP has tentatively chosen a quarry pit at Bagalur that was recently closed as the possible site for the study.
The proposal has been submitted to the Science and Engineering Research Board for financial support under IMPacting Research Innovation and Technology (IMPRINT).
The BBMP has committed to fund 25% of the cost estimated to be around ₹2 crore. Civil work required include installation of points for checking and monitoring groundwater contamination, installation of vertical wells for leachate extraction and recirculation, and monitoring systems for gases and leachate.
“Remediating these sites would not only recover valuable land and air space, and prevent environmental degradation, but also provide a sustainable approach to handling solid waste in the city,” said Dr. Babu.
BBMP’s Special Commissioner (Solid Waste Management) D. Randeep said the project would outline an approach with regard to taking up bio-remediation of dumpsites. Though some quarry pits had already been soil capped, bio-remediation is essential to extract the leachate and gases. “This is a relatively new area. The results of the study can be analysed, which will help the BBMP take up bio-remediation in other sites,” he added.
What is bio-remediation
Bio-remediation is one of the methods of rehabilitating dumpsites in a controlled manner through steps such as installation of vertical wells for leachate recirculation, which may help mitigate the effects of green house gas emissions. Solid Waste Management Rules, 2016, stress on the need to rehabilitate existing dumpsites using suitable waste processing techniques and/or bio-remediation activity.
