title: Application of low intensity ultrasound to enhance the activity of anammox microbial consortium for nitrogen removal.
abstract: In this study, effect of low intensity ultrasound on the activity of anammox microbial consortium for nitrogen removal was investigated through batch experiments at the same irradiation frequency of 25 kHz. Total nitrogen removal rate increased by about 25.5% when ultrasound intensity of 0.3 w cm(-2) was applied at an optimal irradiation time of 4 min, and further experiments demonstrated that this effect could last for about 6 days. Analysis of extracellular polymeric substances indicated that the maximum increase of carbohydrate, protein and total extracellular substances was obtained on the first day after ultrasound, which was 28.8%, 30.5% and 29.7%, respectively. As the time prolonged, the production rate of extracellular carbohydrate, protein decreased gradually. Transmission electron microscopy observation demonstrated that ultrasounded cell wall of anammox microbial consortium became thinner resulting in increased release of extracellular substances. The results suggested that application of low intensity ultrasound may enhance the activity of anammox microbial consortium and ultimately the potential for nitrogen removal.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China.
authors.forename: Xiumei
authors.initials: X
authors.lastname: Duan
authors.forename: Jiti
authors.initials: J
authors.lastname: Zhou
authors.forename: Sen
authors.initials: S
authors.lastname: Qiao
authors.forename: Haifeng
authors.initials: H
authors.lastname: Wei
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism* / Q000648:ultrastructure; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods*; D002473:Cell Wall / Q000378:metabolism* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009584:Nitrogen / Q000302:isolation & purification* / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D000644:Quaternary Ammonium Compounds; D009584:Nitrogen