Anaerobic Membrane Bioreactor Effluent Reuse: A Review of Microbial Safety Concerns

Abstract

Broad and increasing interest in sustainable wastewater treatment has led a paradigm shift towards more efficient means of treatment system operation. A key aspect of improving overall sustainability is the potential for direct wastewater effluent reuse. Anaerobic membrane bioreactors (AnMBRs) have been identified as an attractive option for producing high quality and nutrient-rich effluents during the treatment of municipal wastewaters. The introduction of direct effluent reuse does, however, raise several safety concerns related to its application. Among those concerns are the microbial threats associated with pathogenic bacteria as well as the emerging issues associated with antibiotic-resistant bacteria and the potential for proliferation of antibiotic resistance genes. Although there is substantial research evaluating these topics from the perspectives of anaerobic digestion and membrane bioreactors separately, little is known regarding how AnMBR systems can contribute to pathogen and antibiotic resistance removal and propagation in wastewater effluents. The aim of this review is to provide a current assessment of existing literature on anaerobic and membrane-based treatment systems as they relate to these microbial safety issues and utilize this assessment to identify areas of potential future research to evaluate the suitability of AnMBRs for direct effluent reuse.

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

“…For example, up to 10 4 gene copies (GC) of beta-lactamase bla TEM gene, 10 2 GC of beta-lactamase bla CTX-M gene, and 10 2 GC of mecA gene were found to be present in phages isolated from sewage [39]. Recent review papers have collated abundance of ARGs determined by qPCR in various wastewater effluent streams [40,41], while others discussed the use of metagenomics to track and perhaps to assign risks that are associated with ARGs [42][43][44]. An extensive elaboration of the various studies has demonstrated the use of these tools, and therefore will not be reiterated in this paper.…”

“…MF, UF, and NF membranes are commonly applied in tandem with activated sludge treatment as an alternative to a settling tank. LRV of bacterial contaminants reported by MBRs are collated in a recent review paper [41]. When comparing the reported influent and effluent abundances of bacteria, it is apparent that membranes are a well-established barrier to remove bacteria at high LRV, but whether these reported LRVs can be translated to ARB would remain unknown.…”

Wastewater Treatment and Biogas Recovery Using Anaerobic Membrane Bioreactors (AnMBRs): Strategies and Achievements

“…However, towards attaining higher efficiency, research focus was moved towards coupling anaerobic bioreactors with membrane filtration units. These systems were seen to offer a more unique and prudent technique over conventional anaerobic method [7]. It simply combines the anaerobic process and membrane technology operating simultaneously.…”

Microbial Resources, Fermentation and Reduction of Negative Externalities in Food Systems: Patterns toward Sustainability and Resilience

“…Some studies proposed pathways towards enhanced nutrient bioavailability [10,[58][59][60] and improved human health/well-being [61][62][63][64] (including microbiome therapies [63][64][65][66]), advances of interest to contrast the adverse effects of some negative externalities. Furthermore, the design of several works looking at reducing resource dissipation, saving energy [52,69], valorising foods by-products [52,70,71], foods wastes [72][73][74], and wastewater [75][76][77]. Finally, some strategies can preserve microbial diversity associated with food fermentation [78][79][80].…”