Membrane Bioreactor-Based Wastewater Treatment Plant in Saudi Arabia: Reduction of Viral Diversity, Load, and Infectious Capacity

Abstract

A membrane bioreactor (MBR)-based wastewater treatment plant in Saudi Arabia was assessed over a nine-month period for virus removal efficiency. Viral diversity was detected using omics-based approaches. Log reduction values (LRV) of Adenoviruses (AdV) and Enteroviruses (EV) were enumerated using digital polymerase chain reaction (dPCR) and assessed for infectivity using fluorescence-based infection assays. MBR treatment was successful in reducing viral diversity. Plant viruses remained abundant in the treated effluent. Human enteric viruses were present in lower abundance than plant viruses, and were reduced by MBR at varying LRV. AdV copy numbers were reduced by 3.7-log. Infectious AdV was not detected in the effluent. EV copy numbers were reduced by 1.7-log post MBR and infectious EV decreased by an average of 2.0-log. Infectious EV was detected in the chlorinated effluent, occasionally in concentrations that approximate to its 50% infectious dose. Overall, results indicated that a MBR-based wastewater treatment plant (WWTP) effectively reduces viral diversity, viral load, and infectious capacity by up to 4-logs. These findings suggest potential concerns associated with plant and human enteric viruses for reuse events in this country. Local guidelines for assessment of treated water quality should take into consideration both infectious viral concentration and LRV.

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

“…In contrast, PMMoV was detected at quantifiable levels, with average concentrations of ð2.58 AE 0.44Þ × 10 1 gc=mL in April and ð2.37 AE 1.05Þ × 10 1 gc=mL in June (p ¼ 0.072). PMMoV has been detected at high concentrations in other MBR filtrates (Jumat et al 2017), thereby indicating its potential to persist through activated sludge systems and pass through MF or UF membranes. Table 3 summarizes the observed LRVs for the MBR.…”

Carbamazepine as a Possible Anthropogenic Marker in Water: Occurrences, Toxicological Effects, Regulations and Removal by Wastewater Treatment Technologies

“…In MBR, this solid-liquid separation is performed by filtration via MF or UF membranes. Effective retention of the activated sludge by the membrane in MBR decouples SRT from HRT, thereby allowing the operation of the activated sludge based bioreactor at higher mixed liquor suspended solid concentration (MLSS) and longer SRT [135,136]. It has been reported in several studies that MBR provides better aqueous phase removal of moderately biodegradable PhACs as compared to the CAS process [126,137].…”

Reusing Treated Wastewater: Consideration of the Safety Aspects Associated with Antibiotic-Resistant Bacteria and Antibiotic Resistance Genes

“…However, it is unclear whether or not these factors, along with other unknown factors, would facilitate exogenous ARGs from wastewater effluent to be taken up via transformation and at what rate. Although the risks of possible downstream ARG amplification are greatly reduced after wastewater treatment, where designs typically achieve 3-4 log removal of bacteria and virus [68,69], the fate and health relevance of exogenous DNA remains largely unknown. Clearly more information on the fate, transport, and health impacts of ARGs in the scope of water reuse is needed.…”