Risk management of viral infectious diseases in wastewater reclamation and reuse: Review

Abstract

Inappropriate usage of reclaimed wastewater has caused outbreaks of viral infectious diseases worldwide. International and domestic guidelines for wastewater reuse stipulate that virus infection risks are to be regulated by the multiple-barrier system, in which a wastewater treatment process composed of sequential treatment units is designed based on the pre-determined virus removal efficiency of each unit. The objectives of this review were to calculate representative values of virus removal efficiency in wastewater treatment units based on published datasets, and to identify research topics that should be further addressed for improving implementation of the multiple-barrier system. The removal efficiencies of human noroviruses, rotaviruses and enteroviruses in membrane bioreactor (MBR) and conventional activated sludge (CAS) processes were obtained by a systematic review protocol and a meta-analysis approach. The log10 reduction (LR) of norovirus GII and enterovirus in MBR were 3.35 (95% confidence interval: 2.39, 4.30) and 2.71 (1.52, 3.89), respectively. The LR values of rotavirus, norovirus GI and GII in CAS processes were 0.87 (0.20, 1.53), 1.48 (0.96, 2.00) and 1.35 (0.52, 2.18), respectively. The systematic review process eliminated a substantial number of articles about virus removal in wastewater treatment because of the lack of information required for the meta-analysis. It is recommended that future publications should explicitly describe their treatment of left-censored datasets. Indicators, surrogates and methodologies appropriate for validating virus removal performance during daily operation of wastewater reclamation systems also need to be identified.

Sapovirus in Wastewater Treatment Plants in Tunisia: Prevalence, Removal, and Genetic Characterization

“…Quantification data for viruses in wastewater commonly include a significant number of nondetects (31). Depending on environmental and physical factors, such as the lack of homogeneity of viral particles in water bodies, formation of aggregates with organic matter, or binding to suspended solids (32), virus density in wastewaters may fall below the quantification limit (nondetect) of the analytical methods employed.…”

Viral Surrogates in Potable Reuse Applications: Evaluation of a Membrane Bioreactor and Full Advanced Treatment

“…Specifically, each qualifying unit process within a treatment train (e.g., ozonation, filtration, etc.) is awarded an LRV for each target pathogen (Sano et al 2016;SWRCB 2016;Amarasiri et al 2017). The sum of the LRVs across the whole treatment train is then calculated for each pathogen and compared against regulatory requirements or public health benchmarks (e.g., 10 −4 annual risk of infection).…”

Norovirus and other Caliciviruses

“…In sewer treatment systems, the primary treatment of simple sedimentation did not show removal of viruses (Simmons, 2011). However, noroviruses are removed in secondary treatments, as systematically reviewed (Sano, 2016). Norovirus log 10 removal by activated sludge systems is estimated to be 1.48 (95% confidence interval (CI): 0.96-2.00) and 1.35 (95% CI: 0.52-2.18) for norovirus GI and GII, respectively.…”

“…Sapovirus was effectively (>2 Log 10 ) removed by MBR (Miura et al, 2015). Log 10 removal efficiency of norovirus GII by MBR is estimated from meta-analysis to be 3.35 (95% CI: 2.39-4.30) (Sano, 2016).…”