Muthia village lies on the eastern periphery of Ahmedabad City and borders a major industrial estate operated by the Naroda Gujarat Industrial Development Corporation(GIDC). Approximately 60,000 tons of sludge from effluent treatment plants and other untreated waste have been dumped along the boundary between the industrial estate and the village over the last decade. These hazardous wastes have leached into the groundwater, which has turned yellow and red. Monsoon rains wash and spread the contaminated sludge over wide areas.
Concept Biotech and the Society for Environmental Protection have been studying contamination in this village since 1996. Blacksmith funded the implementation of a three phase clean-up, the last phase of which is the treatment of the site with vermiculture – using worms – which concentrate heavy metals in their bodies, and reduce contamination in the soil.
Originally a site containing an estimated 150 tons of hazardous wastes had been targeted for initiating a pilot-scale intervention project. But when the project commenced, it was discovered that the dumps extended deep into the ground and needed to be excavated. Heavy machinery and equipment were hired for this purpose. Eventually nearly 3,000 tons of hazardous wastes were excavated from the project site and sent to the hazardous waste disposal facility operated by the Naroda Enviro Projects Ltd (NEPL). The costs of this lifting, which were much greater than the project could have afforded, were borne by local industry, which was a major contribution to the project.
The remaining contaminated ground was then treated with active bacterial inoculants to which five tons of vermi-castings were applied after tilling. In two phases during the monsoon season, around 1,200 litres of solution was applied. The application of worm culture was done every three months after tilling and mulching the soil.
This first plot affected by dumping has been remediated with approximately 60 percent reduction in select heavy metals, although another round of de-contamination was recommended. The second round of de-contamination using vermin-technology was undertaken. This year approximately 400L of EM solution was applied, followed by the introduction 8 tons of vermin-cast and 40 kg worms. The resulst at the end of the second year have proved encouraging with further reduction in the levels of heavy metals. In the last and final year of treatment, a further application of 15 MT Vermi-compost was applied to the soil, and the soil was turned mechanically with a tractor to enable the nutrients to reach the sub surface soil depth.
The plot is being monitored every quarter to evaluate the effectiveness of this technology by soil testing and analysis of heavy metals in plant residue.
Project Metrics and Results:
This low-cost pilot bio-remediation method has proved highly effective in managing & treating the waste dumps country-over. The technical solutions to treat toxic dumps are available and can be applicable.
Soil & Grass Sample Analysis Report
Basic soil analysis before start of project (prior to cleanup activity)
The effectiveness of the approach can be seen in the reduction of 90 percent in the levels of the toxic metal chromium.
In 2008-2009, industrial activity, including roadwork and the construction of a store near the test plot, affected the results of the topsoil samples tested. The overall approach and treatment process, however, has proved cost-effective and a feasible solution for cleaning up contaminated soil in and around industrial zones.
Outcomes and Follow-up:
The successful demonstration of this project has built confidence among the Gujarat State Pollution Control Board (the state regulatory body) to invite us to treat similar sites in Gujarat.
This project was documented by CNN International and aired across the globe in October 2007. (Ref: www.cnn.com/ecosolutions - see Archive; worms).
Other references: http://www.dnaindia.com/india/report_after-muthia-golden-corridor-toxins-in-worms-crosshairs_1230363