Removal of antibiotic resistance genes in an anaerobic membrane bioreactor treating primary clarifier effluent at 20 °C

Abstract

Anaerobic membrane bioreactors (AnMBR) play a key role in future plans for sustainable wastewater treatment and resource recovery because they have no energy-intensive oxygen transfer requirements and can produce biomethane for renewable energy. Recent research results show that they can meet relatively stringent discharge limits with respect to BOD 5 and TSS when treating municipal wastewater primary effluent. Sustainable used water recovery plans should also consider removal of unregulated pollutants. Antibiotic resistance genes (ARGs) represent an important emerging contaminant due to public health concerns surrounding the spread of infections resistant to common antibiotics. Conventional activated sludge processes have demonstrated mixed results regarding ARG removal. The objective of this research was to determine the impact of an AnMBR on ARG removal when treating municipal primary clarifier effluent at 20°C. AnMBR treatment resulted in 3.3 to 3.6 log reduction of ARG and the horizontal gene transfer determinate, intI1, copies in filtrate. Membrane treatment significantly decreased the total biomass as indicated by a decrease in 16S rRNA gene concentration. Microbial community analysis via Illumina sequencing revealed that the relative abundance of putative pathogens was higher in membrane filtrate compared to primary effluent although the overall bacterial 16S rRNA gene concentrations was lower in filtrate. Membrane treatment also substantially reduced microbial diversity in filtrate compared to anaerobic reactor contents.Mainstream anaerobic wastewater treatment is a promising technology for sustainable water resource recovery. Anaerobic membrane bioreactors (AnMBRs) can meet relatively stringent BOD 5 and TSS regulatory standards (BOD 5 <10 mg L −1 , TSS <10 mg L −1 ) for municipal wastewater at temperatures as low as 10°C. The research reported herein demonstrated that AnMBR technology can also significantly reduce antibiotic resistance gene copies.

Inhibition during Anaerobic Co-Digestion of Aqueous Pyrolysis Liquid from Wastewater Solids and Synthetic Primary Sludge

“…Dual hierarchical clustering and heatmap construction were performed using the seven dominant archaeal and 50 dominant bacterial OTUs based on relative abundance values. Analysis was performed to identify OTU abundance value differences (p < 0.001) between control, catalyzed APL and non-catalyzed APL digesters using the negative binomial test as implemented in the DESeq2 package [29,30]. The 223 major archaeal and bacterial OTUs with relative abundance >0.1% in at least three samples were used in DEseq2 analysis.…”

Cast iron drinking water pipe biofilms support diverse microbial communities containing antibiotic resistance genes, metal resistance genes, and class 1 integrons

“…The manufacturer's protocol was followed with the exception that initial cell lysis was conducted using liquid nitrogen freeze thaw cycling (3×). [37][38][39][40] DNA concentrations in resulting extracts were quantified by microspectrophotometry using a Nano-Drop (Nano-Drop™ Lite, Thermo Scientific, Waltham, MA) and stored at −20°C.…”

Treatment Processes for Microbial Resistance Mitigation: The Technological Contribution to Tackle the Problem of Antibiotic Resistance

“…Membrane bioreactors have been recently used to remove ARB and ARGs efficiently. For instance, Kappell et al (2018) [100] reported that a ceramic membrane (0.05-µm pore size) coupled externally to an anaerobic fluidized bed reactor could achieve a 3.3-3.6 log reduction of erm(B), tet(O), and sul1 as well as the horizontal gene transfer determinate intI1. [101] evaluated the removal of antibiotics (ampicillin, erythromycin, tetracycline, kanamycin, and ciprofloxacin), ARB (Aeromonas, Escherichia, Klebsiella, and Bacteroides), and ARGs (ermB, tetO, tetW, and intI1) in five full-scale MBRs (membrane pore size < 0.4 µm).…”