Enteric virus in reclaimed water from treatment plants with different multi-barrier strategies: Trade-off assessment in treatment extent and risks

Abstract Reclaimed water is an alternative water resource to mitigate water scarcity. To promote safe reuse, this paper aims to monitor the enteric virus concentration in the reclaimed water generated by two sewage treatment plants (STP) with different multibarrier technologies, and to assess if stringent treatment extent is required in a low-resource setting to achieve minimal viral risks arising from non-potable reuse. Through a 9-month surveillance, it was observed that a higher diversity and abundance of enteric DNA and RNA viruses were detected in treated wastewater generated from conventional activated sludge (i.e., site B) compared to that from membrane bioreactor-based STP (i.e., site A). To exemplify, enteric RNA viruses were detected in up to 1.13, 4.1, 4.9, 4.5, and 4.5 log10 copies/L for Aichi virus (AiV), rotavirus (RV), norovirus GI and GII (NoV GII, GII) respectively, at site B. For enteric DNA virus, up to 4.3 and 5.35 log10 copies/L of adenovirus (AdV) and polyoma BK virus (BKV) were also found in site B. This is in contrast to the absence of AiV, RV and NoV detected in samples from site A. However, when translated to risks outcome from NoV GII, it was noted that recreational users at both sites A and B are exposed to acceptable disease burden (