Biofouling of reverse-osmosis membranes during tertiary wastewater desalination: microbial community composition.
Reverse-osmosis (RO) desalination is frequently used for the production of high-quality water from tertiary treated wastewater (TTWW). However, the RO desalination process is often hampered by biofouling, including membrane conditioning, microbial adhesion, and biofilm growth. The vast majority of biofilm exploration concentrated on the role of bacteria in biofouling neglecting additional microbial contributors, i.e., fungi and archaea. To better understand the RO biofouling process, bacterial, archaeal and fungal diversity was characterized in a laboratory-scale RO desalination plant exploring the TTWW (RO feed), the RO membrane and the RO feed tube biofilms. We sequenced 77,400 fragments of the ribosome small subunit-encoding gene (16S and 18S rRNA) to identify the microbial community members in these matrices. Our results suggest that the bacterial, archaeal but not fungal community significantly differ from the RO membrane biofouling layer to the feedwater and tube biofilm (P < 0.01). Moreover, the RO membrane supported a more diverse community compared to the communities monitored in the feedwater and the biofilm attached to the RO feedwater tube. The tube biofilm was dominated by Actinobacteria (91.2 ± 4.6%), while the Proteobacteria phylum dominated the feedwater and RO membrane (at relative abundance of 92.3 ± 4.4% and 71.5 ± 8.3%, respectively), albeit comprising different members. The archaea communities were dominated by Crenarchaeota (53.0 ± 6.9%, 32.5 ± 7.2% and 69%, respectively) and Euryarchaeota (43.3 ± 6.3%, 23.2 ± 4.8% and 24%, respectively) in all three matrices, though the communities' composition differed. But the fungal communities composition was similar in all matrices, dominated by Ascomycota (97.6 ± 2.7%). Our results suggest that the RO membrane is a selective surface, supporting unique bacterial, and to a lesser extent archaeal communities, yet it does not select for a fungal community.
Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede-Boqer Campus, 84990, Israel. Electronic address: ashraf.ashhab@gmail.com.
Ashraf
A
Al Ashhab
Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede-Boqer Campus, 84990, Israel. Electronic address: herzberg@bgu.ac.il.
Moshe
M
Herzberg
Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede-Boqer Campus, 84990, Israel. Electronic address: gilloro@bgu.ac.il.
Osnat
O
Gillor
D001105:Archaea / Q000254:growth & development; D001419:Bacteria / Q000254:growth & development; D001673:Biodegradation, Environmental; D044822:Biodiversity; D018441:Biofilms; D057219:Biofouling; D019149:Bioreactors / Q000382:microbiology; D005658:Fungi / Q000254:growth & development; D008567:Membranes, Artificial; D059013:Microbial Consortia; D008855:Microscopy, Electron, Scanning; D009995:Osmosis; D025341:Principal Component Analysis; D012965:Sodium Chloride / Q000302:isolation & purification*; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
D008567:Membranes, Artificial; D012965:Sodium Chloride; D062065:Wastewater
ANOSIM; Analysis of similarity; Archaea; Archaea tag-encoded FLX amplicon pyrosequencing; Bacteria; Bacteria tag-encoded FLX amplicon pyrosequencing; Biofouling; Fungi; Fungi tag-encoded FLX amplicon pyrosequencing; HG-MBR; Hybrid growth membrane bioreactor; H′; ICP-OES; Inductively coupled plasma-optical emission spectrometry; Municipal wastewater; OTU; Operational taxonomic unit; PCA; PCR; Polymerase chain reaction; Principal component analysis; RO; Reverse osmosis; Reverse osmosis membrane; Richness estimator, chao1 index; S; SEM; Scanning electron microscope; Shannon-Weaver index; TNA; TTWW; Tertiary treated wastewater; Total nucleic acid; UF; Ultrafiltration; aTEFAP; bTEFAP; fTEFAP