Assam: IIT Guwahati researchers discover promising solution for safe disposal of pathogenic waste

Researchers at the esteemed Indian Institute of Technology Guwahati have made a significant breakthrough in addressing the challenge of managing pathogenic waste in the aftermath of the COVID-19 pandemic. Their study, published in the renowned American Chemical Society journal, Langmuir, unveils a promising solution for the safe disposal of pathogenic waste through the use of compacted natural clays.

The study, co-authored by Prof. Bharat Venkata Tadikonda, Prof. Sachin Kumar, and their research scholars, Himanshu Yadav and Shubham Gaurav, highlights the critical need for proper waste management protocols due to the risks posed by biomedical waste containing viruses. The COVID-19 pandemic led to a surge in potentially virulent waste generated by hospitals and isolation facilities, which was often treated similar to municipal solid waste (MSW) and disposed of in existing landfills.

However, the researchers discovered that the geosynthetic landfill liners used in MSW facilities become ineffective in the presence of landfill leachate containing high-concentration salt solutions. This could lead to the escape of infectious viral pathogen waste, potentially causing secondary infections in humans. The urgency for appropriate management and safe disposal protocols has never been clearer.

Prof. T.V. Bharat from the Department of Civil Engineering at IIT Guwahati explained the rationale behind their research, stating, "We aimed to understand how viruses behave in the presence of compacted clays like bentonite and kaolin, which possess various surface charge densities. Through our measurements of specific parameters such as equilibrium sorption, diffusion coefficient, and retardation factor, we observed a remarkable 99.6% reduction in viral contamination and very low diffusion rates. This experimental evidence confirms the efficiency of using compacted clays to contain viral waste."

To study virus behavior in clays, the researchers employed the Newcastle disease virus (NDV) as a surrogate for the coronavirus. By conducting experiments involving the interaction of the virus with bentonite and kaolin clays for varying durations, as well as through-diffusion tests, they demonstrated the high effectiveness of both types of clays in reducing viral concentrations.

Prof. Sachin Kumar from the Department of Biosciences and Bioengineering at IIT Guwahati added, "The choice of Newcastle disease virus (NDV) as a surrogate for the coronavirus was based on its similarity to the coronavirus in terms of being a single-stranded enveloped RNA virus. This research not only addresses the disposal of pathogenic waste generated during the COVID-19 pandemic but also has implications for waste management during outbreaks of diseases like the Newcastle disease in poultry."

The research findings further revealed that bentonite exhibited faster viral decay compared to kaolin clay. The removal efficiency of the NDV depended on the quality of bentonite and the multilayer sorption of the virus on clay surfaces.

In addition to its immediate implications, this groundbreaking study opens doors for more effective waste management strategies during disease outbreaks. The proposed handling protocol involves the use of biomedical waste facilities with compacted powder Bentonite/Kaolin clays as liners or placing pathogenic waste in closed containers with compacted powder bentonite or kaolin clays for disposal in existing MSW landfills.

The study was supported by the Science and Research Board (SERB), Department of Science and Technology, Government of India, under the research project titled "Attenuation Ability of Municipal Solid Waste Landfill Liners for Viral Pathogens"