title: Ultrasonic Treatment Enhanced Ammonia-Oxidizing Bacterial (AOB) Activity for Nitritation Process.
abstract: Oxidation of ammonia to nitrite rather than nitrate is critical for nitritation process for wastewater treatment. We proposed a promising approach by using controlled ultrasonic treatment to enhance the activity of ammonia-oxidizing bacteria (AOB) and suppress that of nitrite-oxidizing bacteria (NOB). Batch activity assays indicated that when ultrasound was applied, AOB activity reached a peak level and then declined but NOB activity deteriorated continuously as the power intensity of ultrasound increased. Kinetic analysis of relative microbial activity versus ultrasonic energy density was performed to investigate the effect of operational factors (power, sludge concentration, and aeration) on AOB and NOB activities and the test parameters were selected for reactor tests. Laboratory sequential batch reactor (SBR) was further used to test the ultrasonic stimulus with 8 h per day operational cycle and synthetic waste urine as influent. With specific ultrasonic energy density of 0.09 kJ/mg VSS and continuously fed influent containing above 200 mg NH3-N/L, high AOB reproductive activity was achieved and nearly complete conversion of ammonia-N to nitrite was maintained. Microbial structure analysis confirmed that the treatment changed community of AOB, NOB, and heterotrophs. Known AOB Nitrosomonas genus remained at similar level in the biomass while typical NOB Nitrospira genus disappeared in the SBR under ultrasonic treatment and after the treatment was off for 30 days.
authors.affiliation: School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.affiliation: School of Environment, Tsinghua University , Beijing 100084, China.|State Key Joint Laboratory of Environment Simulation and Pollution Control, Beijing 100084, China.
authors.forename: Yan-Chen
authors.initials: YC
authors.lastname: Liu
authors.affiliation: College of Environmental Science and Engineering, Ocean University of China , Qingdao 266100, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Xin
authors.affiliation: School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zuo
authors.affiliation: School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Cheng-Wen
authors.initials: CW
authors.lastname: Wang
authors.affiliation: Department of Civil & Environmental Engineering, the William & Cloy Codiga Resource Recovery Research Center, Center for Sustainable Development & Global Competitiveness, Stanford University , Stanford, California 94305, United States.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wu
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001419:Bacteria; D020562:Betaproteobacteria; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D007700:Kinetics; D059013:Microbial Consortia / Q000528:radiation effects*; D009566:Nitrates; D009573:Nitrites; D009606:Nitrosomonas / Q000528:radiation effects; D010084:Oxidation-Reduction; D012722:Sewage; D014465:Ultrasonics / Q000379:methods*; D062065:Wastewater / Q000382:microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D000641:Ammonia; D009566:Nitrates; D009573:Nitrites; D012722:Sewage; D062065:Wastewater