title: Use of low frequency and density ultrasound to stimulate partial nitrification and simultaneous nitrification and denitrification.
abstract: Low frequency and density ultrasound has attracted considerable attention in enhancing wastewater treatment performance, particularly in the removal of nitrogen. In the present study, two sequencing batch reactors were operated to confirm the effects of ultrasound at the frequency of 40 kHz and density of 0.027 W/mL on partial nitrification and simultaneous nitrification and denitrification (SND). At the optimal irradiation time of 2.0 h, the obtained nitrite accumulation ratio and SND efficiency at full aerobic were 73.9% and 72.8%, respectively. Nitrite accumulation was the result of increased NH4(+)-N removal and improved ammonia oxidizing bacteria (AOB) activity with simultaneous inhibition of nitrite oxidizing bacteria (NOB) activity. Ultrasonic treatment could provide suitable conditions in temperature and pH for AOB growth, and destroy the NOB community structure. Moreover, organic matters were released and offered an additional carbon source for denitrification apart from the negative effects on sludge properties.
authors: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: zm08@mails.tsinghua.edu.cn.
authors: Min
authors: M
authors: Zheng
authors: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: liuyc@mail.tsinghua.edu.cn.
authors: Yan-Chen
authors: YC
authors: Liu
authors: School of Environment, Tsinghua University, Beijing 100084, China.
authors: Kang-Ning
authors: KN
authors: Xu
authors: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: wangcw@tsinghua.edu.cn.
authors: Cheng-Wen
authors: CW
authors: Wang
authors: University of Science and Technology Beijing, Beijing 100083, China.
authors: Hui
authors: H
authors: He
authors: School of Environment, Tsinghua University, Beijing 100084, China.
authors: Wei
authors: W
authors: Zhu
authors: School of Environment, Tsinghua University, Beijing 100084, China.
authors: Qian
authors: Q
authors: Dong
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry*; D058440:Denitrification; D006863:Hydrogen-Ion Concentration; D058465:Nitrification; D009573:Nitrites / Q000737:chemistry*; D009584:Nitrogen; D010100:Oxygen / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014465:Ultrasonics; D014463:Ultrasonography; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater; D018508:Water Purification / Q000379:methods*
chemical_list: D000641:Ammonia; D002244:Carbon; D009573:Nitrites; D009584:Nitrogen; D010100:Oxygen; D012722:Sewage; D062065:Wastewater
keywords: Biological activity; Microbial community structure; Partial nitrification; Simultaneous nitrification and denitrification; Ultrasound irradiation