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The COVID-19 pandemic exposed the challenges of safe disposal of medical waste, especially in countries like India that struggle with segregation and treatment of solid waste.
The fear of contamination from the large volume of pathogenic waste generated during the pandemic set off many studies and the latest among them is one by the Indian Institute of Technology-Guwahati (IIT-G) that proposes the use of compost natural clay to neutralise pathogens in waste.
The waste from hospitals and residences of COVID-19 patients was treated in the same way as municipal solid waste (MSW) during the pandemic and was disposed of in the existing MSW landfills, highlighted the scientists in a press statement made June 19, 2023.
Leachate in these landfills contain high concentrations of salts that can render landfill liners ineffective, they added. This can help pathogens enter the surrounding environment and infect locals.
Bharat Venkata Tadikonda, co-author of the report, wrote in the release:
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.
The measurements showed 99.6 per cent reduction of viral contamination and very low diffusion rates, he added.
“Based on these findings, we were able to confirm that both bentonite and kaolin clays in powder form can prevent the viral contamination from entering into the environment,” Tadikonda stated.
During the experiment, the researchers studied the behaviour of the Newcastle disease virus (NDV), a safer substitute for the coronavirus, in clay, reported news agency Press Trust of India.
“NDV 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,” said Sachin Kumar, department of biosciences and bioengineering, IIT-G.
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.