Meet Dr Ajay S Kalamdhad, a professor of civil engineering at IIT-Guwahati. Passionate about solid waste management, he is leading a team dedicated to tackling organic waste sustainably and efficiently.

Under the Waste Management Research Group (WMRG), Dr Kalamdhad and his team developed an innovative two-stage biodegradation technique combining Rotary Drum Composting (RDC) with Vermicomposting (RDVC).

This innovative method produces nutrient-rich vermicompost, containing 4.2% total nitrogen, in just 27 days. This outpaces the standard 45–60 days, all while reducing waste volume by 71%.

“The developed technique combines the thermophilic biodegradation of RDC with mesophilic biodegradation of vermicompost,” explains Dr Kalamdhad. “RDC prepares organic waste for faster vermicomposting.”

“To explain in layman’s terms: if you use RDC before vermicomposting, it helps vermiculture (earthworms) stabilise the organic waste faster,” he adds.

The team tested diverse biomasses like vegetable waste, aquatic weeds, terrestrial weeds, and sewage sludge. A 5,000-litre RDC unit and a 3,000-litre vermicomposting unit validated the process on a large scale.

PhD student Suryateja Pottipati experimentally verified the technique, with findings published in journals like the Journal of Biomass Conversion and Biorefinery and Bioresource Technology.

The result? ‘Mati Dhan’ — a high-quality, nutrient-rich vermicompost developed from waste — is now available to farmers through AMER Private Ltd, an IIT-Guwahati incubated startup. They can also get it online on Amazon.

“This proven technique not only handles sizable quantities of organic waste but also offers immediate application feasibility for municipal corporations, industries, sewage treatment facilities, aquatic weeds, etc,” says Dr Kalamdhad.

The scaled-up process successfully produced 100 to 150 kg of vermicompost within a month from 250 to 300 kg of daily waste fed. The increased earthworm population also served as a secondary by-product.

“In the entire study, we converted 15 tonnes of waste collected from the markets and ponds around the IIT Guwahati campus (350 kg per day). The confidence that we gained through the study is the basis on which we are suggesting that the technology can handle sizable quantities,” Dr Kalamdhad adds.

Backed by the Department of Science and Technology, the RDVC method is leading the charge for eco-friendly, scalable waste management solutions.