IIT-G study finds compacted clays can prevent viral contamination from entering environment

Guwahati: Researchers at Indian Institute of Technology (IIT) Guwahati, have found a solution to the challenge of managing pathogenic waste in the post-COVID-19 pandemic period.

After studying the fate and transport of virus through compacted natural clays for pathogenic waste disposal, the researchers found that both bentonite and kaolin clays in powder form can prevent the viral contamination to enter the environment, a press release issued by the premier institution said on Monday.

The study has been published in the American Chemical Society journal ‘Langmuir’. The paper has been co-authored by Prof. Bharat Venkata Tadikonda, Prof. Sachin Kumar and their research scholars, Himanshu Yadav and Shubham Gaurav.

Biomedical waste (BMW) that contains viruses poses significant risks to human health, food safety, animal health and the environment.

During the pandemic, a huge quantity of potentially virulent waste was produced from hospitals and isolation facilities.

The coronavirus waste was treated similar to municipal solid waste (MSW) during the pandemic and was disposed of in the existing MSW landfills, the release said.

However, the geosynthetic landfill liners become ineffective in the presence of landfill leachate containing high-concentration salt solutions and so infectious viral pathogen waste can then easily escape from such facilities to cause secondary infections in humans.

Explaining the rationale of the research, Prof. Bharat, department of Civil Engineering IIT-Guwahati, said, “We wanted to understand the fate of viruses in the presence of compacted clays like bentonite and kaolin that contain various surface charge densities. We measured specific parameters like the equilibrium sorption parameters, diffusion coefficient and retardation factor of the virus in the compacted clays for the first time.

“These measurements showed 99.6 per cent reduction of viral contamination and very low diffusion rates. Based on these findings, we were able to confirm that both bentonite and kaolin clays in powder form can prevent the viral contamination to enter into the environment.”

Prof. Bharat added that their study for the first time provides experimental evidence of the efficiency of using compacted clays for containing viral waste.

To study the behaviour of viruses in clays, the researchers used a safe virus called the Newcastle disease virus (NDV) as a substitute for the coronavirus.

“NDV could be a surrogate to the coronavirus. Newcastle disease is an infectious and contagious viral infection that affects more than 250 different bird species worldwide. A large amount of pathogenic waste gets generated from NDV outbreaks in the form of carcasses, potentially contaminated litter, farm bedding and fomites,” Prof. Sachin Kumar, department of Biosciences and Bioengineering, IIT-Guwahati, said.

The research findings revealed that viral decay was quicker on bentonite compared to kaolin clay. It was observed that the removal efficiency of the NDV depended on the quality of bentonite and multilayer sorption of the virus on clay surfaces.

In addition to addressing the disposal of pathogenic waste generated from the COVID-19 pandemic, the study also has implications for waste management during outbreaks of diseases like the Newcastle disease in poultry, the release said.