Unveiling the viral escape: Quantification of microfloc-bound viruses in precoagulation and membrane filtration

The implementation of precoagulation before the physical removal process is expected to achieve a high virus removal rate. However, viruses may form small flocs and subsequently escape into the effluent during physical removal processes. This study evaluated how viruses in the microflocs could be qu...

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Bibliographic Details
Main Authors: Midori Yasui, Hiroyuki Katayama
Format: Article
Language:English
Published: IWA Publishing 2024-02-01
Series:Journal of Water and Health
Subjects:
Online Access:http://jwh.iwaponline.com/content/22/2/309
Description
Summary:The implementation of precoagulation before the physical removal process is expected to achieve a high virus removal rate. However, viruses may form small flocs and subsequently escape into the effluent during physical removal processes. This study evaluated how viruses in the microflocs could be quantified using conventional virus quantification methods (plaque assay and quantitative polymerase chain reaction (qPCR)) to reveal the risk of underestimating virus concentration. In this study, the microfloc dissolution phenomenon in phosphate buffer solution was employed as a floc dissolution test. Viruses in microflocs formed under the experimental conditions. assuming water treatments, were quantified before and after floc dissolution. The findings revealed that virus concentrations increased by 1.0–3.9 log plaque-forming units/mL according to the plaque assay and by 1.7–4.0 log copies/mL according to the qPCR. This increase occurred after the dissolution of microflocs that were prepared in the humic acid test water. In the case of treated wastewater, virus concentrations increased in all samples according to the plaque assay and in seven of eight samples according to the qPCR. Our results indicate the necessity of careful consideration of virus quantification after precoagulation and physical removal systems. HIGHLIGHTS Microfloc-bound viruses were quantified using plaque and qPCR assays.; Microflocs were dissolved in phosphate buffer.; Virus concentration increased after floc dissolution, as quantified using the two methods.; Microfloc leakage can cause viral risk underestimation.;
ISSN:1477-8920
1996-7829