MABing-bing,ZHANGXiao-jing,ZHANGNan,et al.Influence of Long-term Hg(Ⅱ) Exposure on Recovery Performance of Interrupted CANON Process[J].China Water & Wastewater,2024,40(17):84-91.
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Influence of Long-term Hg(Ⅱ) Exposure on Recovery Performance of Interrupted CANON Process

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第40卷 Number: 第17期 Page: 84-91 Column: Date of publication: 2024-09-01
Author(s):
MA　Bing-bing;  ZHANG　Xiao-jing;  ZHANG　Nan;  ZHANG　Han;  ZHANG　Jia-jie;  GONG　Yao-yao;  ZUO　Qi-yue
（Henan Collaborative Innovation Center for Environmental Pollution Control and Ecological Restoration， School of Materials and Chemical Engineering， Zhengzhou University of Light Industry， Zhengzhou 450001， China）
Keywords:
CANON process;  sludge activity recovery;  Hg(Ⅱ);  Anammox
Abstract:
To explore the impacts of long-term Hg(Ⅱ) exposure on the recovery performance of an interrupted CANON process, two reactors, namely one without Hg(Ⅱ) exposure (R1) and the other with Hg(Ⅱ) exposure (R2), were employed to prolong the hydraulic retention time and regulate the dissolved oxygen to 0.1 mg/L, and the nitrogen removal performance was restored when the influent ammonia nitrogen was 200 mg/L. After 55 days of operation, the total nitrogen removal efficiency and total nitrogen removal rate of R1 recovered from -24.7% and -0.201 kg/(m3·d) to (68.8±10.8)% and (0.273±0.043) kg/(m3·d) respectively. However, the total nitrogen removal efficiency of R2 consistently remained below 30% after 52 days of operation, while the nitrite nitrogen accumulation rate was (93.5±6.5)%, and the CANON system was transformed into a partial nitrification system. Hg(Ⅱ) was detected at a concentration of 6.0 μg/L in the R2 effluent during the initial stage of recovery, and the anaerobic ammonia-oxidizing bacteria (AnAOB) were constantly inhibited by Hg(Ⅱ). The outcomes of high-throughput sequencing indicated that the relative abundances of AnAOB and aerobic ammonia oxidizing bacteria in R1 were 16.0% and 0.6% prior to cut-off, 9.4% and 21.0% before recovery, and 4.8% and 4.8% after recovery, respectively. The corresponding values in R2 were 10.3% and 0.5% before cut?off, 10.8% and 0.5% before recovery, and 8.4% and 11.9% after recovery. The idle sludge after long-term exposure to Hg(Ⅱ) was unable to restore high nitrogen removal performance, but could be utilized as a source of partial nitrifying sludge.
Last Update: 2024-09-01