The infection with SARS-CoV-2 is reported to be accompanied by the shedding of the virus in fecal samples of infected patients. Earlier reports have suggested that COVID-19 agents can be present in the sewage samples and thus it can be a good indication of the pandemic extent in a community. However, no such studies have been reported in the Indian context. Hence, it becomes absolutely necessary to detect the presence of the SARS-CoV-2 in the wastewater samples from wastewater treatment plants (WWTPs) serving different localities of Jaipur city. Samples from different WWTPs and hospital wastewater samples were collected and wastewater based epidemiology (WBE) studies were carried out using the RT-PCR to confirm the presence of different COVID-19 target genes namely S gene, E gene, ORF1ab gene, RdRp gene and N gene. The results revealed that the untreated wastewater samples showed the presence of SARS-CoV-2 viral genome, which was correlated with the increased number of COVID-19 positive patients from the concerned areas, as reported in the publically available health data. This is the first study that investigated the presence of SARS-CoV-2 viral genome in wastewater, at higher ambient temperature (45 °C), further validating WBE as potential tool in predicting and mitigating outbreaks.

A comparative study was performed to treat the domestic wastewater through two different epigeic earthworms (Eisenia fetida and Eudrilus eugeniae) based vermifiltration unit (VF1 and VF2). Results revealed a significant removal of biochemical oxygen demand (88%), total suspended solids (78%), and total dissolved solids (75%) in the treated wastewater from VF1; while in VF2, it was observed to be 70, 67, and 66%, respectively, at hydraulic loading rate (HLR) of 2.5 m³m⁻²d⁻¹. Beside this, a significant reduction of total coliform (3.1 log) was observed in VF1 as compared with 0.98 log reduction in VF2. In addition to this, an increase in earthworm biomass in reactor VF1 was found to be 11.4%; while in VF2, mortality was observed, since the earthworm species E. eugeniae could not survive during the process. Overall, in VF1, the effluent was rich in nitrate, phosphate, and showed the potential of E. fetida for wastewater treatment during vermifiltration process.

The present study brings insight to the antimicrobial activity of isolated bacterial species in a vermifilter (VF) during the combined treatment of domestic wastewater and organic fraction of municipal solid waste (OFMSW). The study showed that vermifilter resulted in an effluent with biochemical oxygen demand (BOD) <20 mg/L and coliforms<103 MPN/100 mL, signifying higher treatment and pathogen removal efficacy. A total of 41 colony forming units (CFU) were isolated, out of which 12 strains were selected, which exhibited higher antimicrobial activity against pathogenic bacteria and fungi. This observation indicated the existence of a mechanism responsible for removal of pathogens, and based on comparative sequence analysis of 16S rRNA genes, the characterized bacterial strains could be subdivided into two phylogenetic clusters: Firmicutes and γ-Proteobacteria. These findings suggested that identified strains contribute to the search for new sources of antimicrobial substances and enhancing the ...