A new approach to assist municipal corporations in managing organic waste has been developed by researchers of the Waste Management Research Group (WMRG) at the Indian Institute of Technology (IIT), Guwahati.
The technique combines Rotary Drum Composting (RDC) with Vermicomposting (RDVC), resulting in an efficient and environmentally friendly process that allows municipal corporations to derive value-added products from organic waste, according to an official statement on Friday.
This technique can also be used to produce nutrient-rich soil conditioner from invasive aquatic weeds like the water hyacinth.
Municipal solid waste deposited in open dumpsites often contains over 50 per cent organic materials, generating substantial heat due to long-term decomposition. This not only poses environmental challenges but also hinders the achievement of sustainable development goals, it added.
Compared to other waste biodegradation techniques that require two to three months, RDC can convert diverse organic feedstocks into nutrient-dense compost within just 20 days and significantly reduce the volume of municipal waste by 60-70 per cent.
However, the limitation of RDC is its inferior compost quality. Vermicomposting, on the other hand, is a superior biodegradation process that traditionally requires a minimum of 60 days, making it less adaptable for urban municipal corporations. By combining the benefits of both processes, WMRG at IIT Guwahati has developed a unique strategy of two-stage biodegradation, the statement said.
Speaking about the novel technique, Prof Ajay S Kalamdhad, department of civil engineering at IIT Guwahati, who led the research, said, “We optimised the RDC technique and combined it with vermicomposting to reduce the duration of biodegradation. The earthworms, Eisenia fetida, can acclimatize faster to partially degraded organic matter from the drum compost and produce vermicompost in just 27 days.”
The microbial composition of the compost was identified through metagenomic analysis. The final product was proven to be non-toxic and safe to be used as a nutrient-rich soil conditioner (with 4.2 per cent total nitrogen) derived from waste.
The combined technique was experimentally verified in both the laboratory and on a large scale at the Solid Waste Laboratory of IIT Guwahati, according to the release.
Prof Kalamdhad said, “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, and various organic waste management sectors.”
The scaled-up process successfully produced 100 to 150 kg of vermicompost within a month from 250kg to 300kg of daily waste fed. The increased earthworm count resulted in the secondary end product being the earthworm itself.
The findings of the study have been published in multiple research papers in the Journal of Biomass Conversion and Biorefinery, Journal of Environmental Management, Bioresource Technology, and Waste Management, among others. They were co-authored by Suryateja Pottipati and Prof. Kalamdhad.
To reach the end-users of the organic bioproducts, the technology has been transferred to The Apshisht Management and Environmental Research Pvt Ltd, a company based in the IIT Guwahati incubation centre.
The product has been marketed as ‘Mati Dhan Organic Vermicompost Fertilizer Manure for Plants’ on online platforms Amazon and INDIAMART, the release added.