Calicivirus Removal in a Membrane Bioreactor Wastewater Treatment Plant

Abstract

To evaluate membrane bioreactor wastewater treatment virus removal, a study was conducted in southwest France. Samples collected from plant influent, an aeration basin, membrane effluent, solid sludge, and effluent biweekly from October 2009 to June 2010 were analyzed for calicivirus (norovirus and sapovirus) by real-time reverse transcription-PCR (RT-PCR) using extraction controls to perform quantification. Adenovirus and Escherichia coli also were analyzed to compare removal efficiencies. In the influent, sapovirus was always present, while the norovirus concentration varied temporally, with the highest concentration being detected from February to May. All three human norovirus genogroups (GI, GII, and GIV) were detected in effluent, but GIV was never detected in effluent; GI and GII were detected in 50% of the samples but at low concentrations. In the effluent, sapovirus was identified only once. An adenovirus titer showing temporal variation in influent samples was identified only twice in effluent. E. coli was always below the limit of detection in the effluent. Overall, the removal of calicivirus varied from 3.3 to greater than 6.8 log units, with no difference between the two main genogroups. Our results also demonstrated that the viruses are blocked by the membrane in the treatment plant and are removed from the plant as solid sludge.

Meta-Analysis of the Reduction of Norovirus and Male-Specific Coliphage Concentrations in Wastewater Treatment Plants

“…Our inference model results estimated that NoV GI and NoV GII influent concentrations were higher from January to May than from June to November, which is consistent with other specific reports in the literature (25,26,53). As an example, Katayama et al (26) reported NoV influent concentrations to be more abundant in winter than in summer, which is consistent with the present model results (Ϯ1 log 10 ; Fig.…”

“…In the peer-reviewed scientific literature, evaluations of log 10 reductions are usually performed by assigning a value (e.g., 0 or LOD [27,61] or one-half the LOD or an arbitrary value [52]) to measurements below the LOD, by ignoring those values (25), or by providing only a lower limit of the actual log 10 reduction (e.g., a log 10 reduction of ՅϪ3.8 [53]). Ignoring censored data or replacing these observations with a given value biases the inference process (62,63).…”

Removal of Pathogens by Membrane Bioreactors: A Review of the Mechanisms, Influencing Factors and Reduction in Chemical Disinfectant Dosing

“…Ottoson et al [21] note that the presence of indicator organisms does not always indicate the presence of pathogens. Conversely, it has been suggested that much of the controversy with regards to indicator and pathogen correlations is the result of studies with insufficient data for assessing correlations [56,126] and these problems can be rectified by taking the appropriate quality control measures. On the other hand, Sima et al [56] pointed out potential pitfalls of the RT-PCR method of quantifying virus genomes due to compounds present in wastewater samples, which may interfere with extraction efficiencies, and raised the importance of careful quality control measures also in this respect.…”

“…On the other hand, because viruses tend to attach to solid surfaces, most viruses that survive wastewater treatment are likely associated with waste-activated sludge and may be present in biosolids [14,56,104]. This warrants safe disposal of potentially pathogen-containing biosolids.…”

Environmental Transmission of Human Noroviruses in Shellfish Waters

“…However, no significant differences in NoV reduction between UV disinfection and UV disinfection plus TiO 2 treatment were found in one study (71). Membrane bioreactor technology, which combines biological-activated sludge processes and membrane filtration, has been reported to remove NoV (GI and GII) at levels ranging from 3.3 to 6.8 log 10 units (72,73).…”