COVID-19 and Recycled Wastewater Irrigation: A Review of Implications

Abstract

Recycled wastewater is considered as a sustainable source of irrigation water. Despite commendable safety records, viral contamination of agricultural products has occurred the past causing disease outbreaks. This review examines the apprehension that the novel coronavirus (SARS-CoV-2) may also spread through recycled wastewater irrigation (RWI) industry. The novel SARS-CoV-2 is now perceived as an enteric pathogen, and has been found to remain stable in the wastewater for days. Mounting evidences also suggest that viral particles shed by infected individuals through sewage, and greywater is much higher (up to 10 Log10) than the amount typically removed (6-7 Log10) through the recycled water disinfection processes. Such gap indicated an increased risk of infection through fecal-oral transmission route. This study also identified greywater irrigation schemes posing a higher risk of transmission of SARS-CoV-2. It was recommended that countries putting greywater in the ‘low risk’ category may rewrite the safety guidelines in post COVID-19 times. This review also suggest that the choice of irrigation method could be critical in protecting the farmers, and the consumers from possible infections during the pandemic. In this regard, irrigation methods (i.e. sprinkler) that generate airborne droplet (leading to aerosols) may be operated with caution when public spaces are in the vicinity. The study also indicated that the developing countries should regulate surface irrigation practice that pump water from polluted rivers during the pandemic.

Sewage analysis as a tool for the COVID-19 pandemic response and management: the urgent need for optimised protocols for SARS-CoV-2 detection and quantification

“…In general, there is lack of data on the effect of various wastewater treatment technologies applied at the UWTPs on SARS-CoV-2 as the first efforts were to firstly identify the virus in the influent of UWTPs. The removal efficiency of SARS-CoV-2 with traditional biological treatment processes such as the Conventional Activated Sludge (CAS) and the Membrane BioReactor (MBR) process, remains unclear due to the absence of experimental data (40[preprint]) . More specifically, the majority of the available data focuses on a large range of surrogate viruses of bacteriophages and laboratory-cultured viruses such as Enterovirus, Adenovirus and human polyomavirus JC, with a large variety of removal exhibited, from 0.9 to 5.8 logs [ 41 ].…”

“…Currently, the potential route of the transmission of SARS-CoV-2 to humans in the wastewater-receiving environments via the reuse practice for agricultural irrigation has not been elucidated. Oliver et al [ 40 ] ([ preprint ]) reported that the selection of irrigation technique is critical for minimising the spread of the virus to the environment and suggested that alternative irrigation techniques, e.g. micro-irrigation, should be considered.…”

Tracking SARS-CoV-2 RNA through the wastewater treatment process

“…6,10–14 Consequently, there has been a recent global interest in monitoring the dissemination of SARS-CoV-2 in municipal sewages, mainly for wastewater-based epidemiology (WBE). 3,15–20 The implication that wastewater is a potential dissemination and infection route, has been also discussed, 13,21–23 however, empirical evidences are still scarce. This is partially due to the current challenge of sample concentration and extraction methods, 24 required for precise virus quantification.…”

The evaluation of Avian Influenza and Coronavirus as Human Pathogenic Enveloped Viruses for Possible Health Risk in Seafood: A Review

“…They also reported that the amount usually removed (6-7 Log10) through the recycled water disinfection methods is much lower than viral particles shedding (up to 10 Log10) by infected people through sewage and greywater. Many researchers have been thought that these results showed an increased potential of contamination through the fecal-oral infection route from the water environment (Bhattacharjee, 2020; Chen et al, 2020b;Holshue et al, 2020;Medema et al, 2020;Oliver et al, 2020;Qu et al, 2020;Xiao et al, 2020a,b).…”