Virus Type-Specific Removal in a Full-Scale Membrane Bioreactor Treatment Process

Area of Science:

• Environmental Microbiology
• Water Treatment Technologies
• Virology

Background:

• Wastewater treatment plants are critical for public health by removing pathogens.
• Membrane bioreactors (MBRs) offer advanced wastewater treatment, but their efficacy against specific enteric viruses requires detailed investigation.

Purpose of the Study:

• To assess the removal efficiency of noroviruses, sapoviruses, and rotaviruses in a full-scale MBR.
• To evaluate the role of virus adsorption to mixed liquor suspended solids (MLSS) in MBR virus removal.

Main Methods:

• Monitoring virus concentrations in wastewater influent and effluent over two gastroenteritis seasons.
• Quantifying virus adsorption to MLSS in solid and liquid phases of MBR samples.
• Comparing adsorption efficiencies of different virus strains (Norovirus GI.1, GII.4; Sapovirus GI.2; Rotavirus G1P[8]) to MLSS.

Main Results:

• Sapoviruses and rotaviruses were detected in 25% of MBR effluent, with log reduction values of 3 and 2, respectively. Noroviruses were found in only 6% of effluent samples.
• Norovirus and sapovirus concentrations were significantly higher in the solid phase of MLSS compared to the liquid phase (P < 0.01).
• Rotavirus adsorption to MLSS was significantly lower than that of norovirus and sapovirus strains (P < 0.01).

Conclusions:

• MBRs demonstrate variable removal rates for different enteric viruses, influenced by their adsorption characteristics to MLSS.
• Virus-type-specific removal in MBRs is likely driven by differences in virus-solid phase interactions.
• Further research into virus-MLSS adsorption mechanisms can optimize MBR performance for enhanced pathogen removal.