Effects of ultrasound on the released amount of nitrogen and phosphorus and changes of water quality during blooms control
TAN Xiao1, GU Hui-hui1, DUAN Zhi-peng1, LI Nie-gui2, JI Yan-ling1
1. Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China;
2. Nanjing Automation Institute of Water Conservancy and Hydrology, Nanjing 210012, China
Ultrasonic technology for controlling cyanobacterial blooms has attracted much attention from the general public. In order to investigate the effects of ultrasonic treatment on water quality deterioration and the amount of nitrogen and phosphorus released from sediments or algal cells. In this study, samples were collected from Meiliang Bay of Taihu Lake, and then, three experimental groups were designed:mixture of sediment and water (sediment system), suspension solution of Microcystis (algae system), and combination of sediment and algae suspension (sediment + algae system), so as to evaluate effects of low-frequency ultrasound (35kHz, 0.035W/mL). Results showed that marked release of nitrogen and phosphorus from sediments seldom occurred within 20min, while prolonged treatment (over 40min) would lead to largely nutrients release and algal cells rupture. Based on the data comparison among three experimental groups, the contribution of nitrogen and phosphorus released from sediments was much greater than that from algal cells. To a certain extent, CODMn and TN could be reduced by ultrasonic treatment. In sediment system and sediment + algae system, dissolved nitrogen mainly existed as ammonia and nitrate forms after treatment. For the sake of water quality safety, the intensity and duration of ultrasonic treatment should be optimized, which means low-intensity and short-time treatment is suggested, so as to avoid nutrients largely released from sediments and algal cells rupture.
谭啸, 顾惠卉, 段志鹏, 李聂贵, 纪艳灵. 超声波控藻对氮磷释放及水质变化的影响[J]. 中国环境科学, 2018, 38(4): 1371-1376.
TAN Xiao, GU Hui-hui, DUAN Zhi-peng, LI Nie-gui, JI Yan-ling. Effects of ultrasound on the released amount of nitrogen and phosphorus and changes of water quality during blooms control. CHINA ENVIRONMENTAL SCIENCECE, 2018, 38(4): 1371-1376.
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