Reflections on Reducing Pathogens in Sludge in the Case of COVID-19 Epidemic

ABSTRACT

Based on the problem that the novel coronavirus (SARS-CoV-2) can enter the urban drainage system through the excretion of patients' faces into the sewer, the fate of infective viruses in the urban water cycle was analyzed. Then, it was concluded that attention should be paid to the risk of virus spreading through sludge after the virus enters the urban drainage system. In the case of COVID-19 epidemic, it is impartant to summarize and reflect on the pathogen control during sludge treatment and disposal process in China. Therefore, the relevant standards and policies of sludge sterilization and disinfection in China have been systematically combed, and the relevant research results of the United States and the European Union have been studied. It has been considered that the sludge is a good carrier of pathogens;the standard restrictions on pathogens in sludge in our country are relatively loose currently. So it is necessary to strengthen the experiments and research on inactivation of pathogens in sludge, and to formulate the index and limit value of pathogens. The SARS-CoV-2 is an enveloped virus that can be relatively easily killed by antivirus agent. Therefore, adding disinfectant to the sludge pretreatment section is an effective measure to control pathogens during the epidemic. Aerobic fermentation, anaerobic digestion, lime stabilization, thermal drying, and radiation treatment can effectively reduce pathogens. During the epidemic period, sludge disposal methods are recommended to adopt incineration or co-incineration. For areas where the harmless disposal capacity of sludge is insufficient, the implementation of compliance sludge disposal outlet should be promoted. In addition, in order to reduce the exposure risk, in the sludge treatment and disposal process, the better sealing device should be preferred.