Assessment of Clay Mineral Attenuation Capacity for Human Viral Pathogens

The current practice of curbing the ill effects associated with the open dumping of biomedical waste (BMW) solely relies on incineration. However, the incineration of BMW and plastic-based medical gear is associated with severe health hazards due to toxic emissions. Many countries are resorting to incineration at unpermitted locations and open dumping due to the enormous surge in the generated BMW during the ongoing pandemic times. Such improper practice of incineration of BMW incineration and open dumping leads to significant environmental pollution. Therefore, an alternative and environmentally sustainable disposal facility is essential to avoid the negative effects of BMW disposal. In this study, the effectiveness of compacted clay-based barrier systems was explored, for the first time, for the encapsulation of virus-contaminated BMW. The model parameters essential for designing such exclusive BMW containment facilities, namely effective diffusion coefficient (De) and retardation factor (Rd) for different clay minerals, were evaluated. The evaluation was based on the limited available batch sorption test and free solution diffusion test data for various hazardous pathogens. The model parameters were utilized to understand the attenuation of viral pathogens (SARS-CoV, poliovirus, and reovirus) and bacteriophages (MS2 and φx-174) in montmorillonite and kaolinite mineral barriers. The selected pathogens were chosen such that they represented SARS-CoV-2 in terms of its surface characteristics. The results from the present study revealed that a 2- to 3- mm thick exclusive clay-based barrier system was sufficient to contain the studied pathogens and SARS-CoV-2 for 50 years.