A survey of biofilms on wastewater aeration diffusers suggests bacterial community composition and function vary by substrate type and time.
Aeration diffusers in wastewater treatment plants generate air bubbles that promote mixing, distribution of dissolved oxygen, and microbial processing of dissolved and suspended matter in bulk solution. Biofouling of diffusers represents a significant problem to wastewater treatment plants because biofilms decrease oxygen transfer efficiency and increase backpressure on the blower. To better understand biofouling, we conducted a pilot study to survey the bacterial community composition and function of biofilms on different diffuser substrates and compare them to those in the bulk solution. DNA was extracted from the surface of ethylene-propylene-diene monomer (EPDM), polyurethane, and silicone diffusers operated for 15 months in a municipal treatment plant and sampled at 3 and 9 months. The bacterial community composition and function of the biofilms and bulk solution were determined by amplifying the 16S rRNA genes and pyrosequencing the amplicons and raw metagenomic DNA. The ordination plots and dendrograms of the 16S rRNA and functional genes showed that while the bacterial community composition and function of the bulk solution was independent of sampling time, the composition and function of the biofilms differed by diffuser type and testing time. For the EPDM and silicone diffusers, the biofilm communities were more similar in composition to the bulk solution at 3 months than 9 months. In contrast, the bacteria on the polyurethane diffusers were more dissimilar to the bulk solution at 3 months than 9 months. Taken together, the survey showed that the community composition and function of bacterial biofilms depend on the diffuser substrate and testing time, which warrants further elucidation.
Department of Periodontics, University of Washington, Box 357444, Seattle, WA, USA.|PhD Program in Microbiology, Alabama State University, Montgomery, AL, USA.
Peter A
PA
Noble
School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul, 136-713, South Korea.|The Henry Samueli School of Engineering, University of California, Irvine, Irvine, CA, USA.
Hee-Deung
HD
Park
The Henry Samueli School of Engineering, University of California, Irvine, Irvine, CA, USA. bholson@uci.edu.
Betty H
BH
Olson
Civil Engineering and Construction Engineering Management, College of Engineering at California State University, Long Beach, CA, USA.
Pitiporn
P
Asvapathanagul
PhD Program in Microbiology, Alabama State University, Montgomery, AL, USA.
M Colby
MC
Hunter
The Henry Samueli School of Engineering, University of California, Irvine, Irvine, CA, USA.
Manel
M
Garrido-Baserba
School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul, 136-713, South Korea.
Sang-Hoon
SH
Lee
The Henry Samueli School of Engineering, University of California, Irvine, Irvine, CA, USA. rossodr@gmail.com.
Diego
D
Rosso
D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D018441:Biofilms; D057219:Biofouling; D004269:DNA, Bacterial / Q000302:isolation & purification; D004058:Diffusion; D020724:Elastomers / Q000737:chemistry; D005030:Ethylenes / Q000737:chemistry; D059013:Microbial Consortia; D010100:Oxygen / Q000378:metabolism; D010865:Pilot Projects; D011140:Polyurethanes / Q000737:chemistry; D025341:Principal Component Analysis; D012336:RNA, Ribosomal, 16S / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D012828:Silicones / Q000737:chemistry; D011795:Surveys and Questionnaires; D013997:Time Factors; D062065:Wastewater / Q000382:microbiology*
D004269:DNA, Bacterial; D020724:Elastomers; D005030:Ethylenes; D010100:Oxygen; D011140:Polyurethanes; D012336:RNA, Ribosomal, 16S; D012828:Silicones; D062065:Wastewater; C505585:ethylene-propylene-diene-monomer
Aeration diffusers; Biofouling; Next-generation sequencing; Wastewater