College of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, China.
College of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, China.
J Environ Manage. 2023 Sep 15;342:118108. doi: 10.1016/j.jenvman.2023.118108. Epub 2023 May 16.
The performance, microbial enzymatic activity and microbial community of a sequencing batch reactor (SBR) were explored under instantaneous Cd(II) shock loading. After a 24-h Cd(II) shock loading of 100 mg/L, the chemical oxygen demand and NH-N removal efficiencies decreased significantly from 92.73% and 99.56% on day 22 to 32.73% and 43% on day 24, respectively, and then recovered to the normal values gradually. The specific oxygen utilization rate (SOUR), specific ammonia oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), specific nitrite reduction rate (SNIRR) and specific nitrate reduction rate (SNRR) decreased by 64.81%, 73.28%, 77.77%, 56.84% and 52.46% on day 23 in comparison with the absence of Cd(II) shock loading, respectively, and they gradually returned to the normal levels. The changing trends of their associated microbial enzymatic activities including dehydrogenase, ammonia monooxygenase, nitrite oxidoreductase, nitrite reductase and nitrate reductase were in accordance with SOUR, SAOR, SNOR, SNIRR and SNRR, respectively. Cd(II) shock loading promoted the microbial reactive oxygen species production and lactate dehydrogenase release, indicating that instantaneous shock caused oxidative stress and damaged to cell membranes of the activated sludge. The microbial richness and diversity, and the relative abundance of Nitrosomonas and Thauera obviously decreased under the stress of Cd(II) shock loading. PICRUSt prediction showed that Cd (II) shock loading significantly affected Amino acid biosynthesis, Nucleoside and nucleotide biosynthesis. The present results are conducive to take adequate precautions to reduce the adverse effect on bioreactor performance in wastewater treatment systems.
在瞬时 Cd(II) 冲击负荷下，探索了序批式反应器 (SBR) 的性能、微生物酶活性和微生物群落。在 100mg/L Cd(II) 冲击负荷 24 小时后，COD 和 NH-N 的去除效率分别从第 22 天的 92.73%和 99.56%显著下降到第 24 天的 32.73%和 43%，然后逐渐恢复到正常水平。比耗氧速率 (SOUR)、氨单加氧速率 (SAOR)、亚硝酸氧化速率 (SNOR)、亚硝酸还原速率 (SNIRR) 和硝酸盐还原速率 (SNRR) 分别比无 Cd(II) 冲击负荷的情况下第 23 天下降了 64.81%、73.28%、77.77%、56.84%和 52.46%，并逐渐恢复到正常水平。脱氢酶、氨单加氧酶、亚硝酸氧化还原酶、亚硝酸还原酶和硝酸盐还原酶等相关微生物酶活性的变化趋势与 SOUR、SAOR、SNOR、SNIRR 和 SNRR 一致。Cd(II) 冲击负荷促进了微生物活性氧的产生和乳酸脱氢酶的释放，表明瞬时冲击造成了活性污泥的氧化应激和细胞膜损伤。在 Cd(II) 冲击负荷的压力下，微生物丰富度和多样性以及硝化菌和陶厄氏菌的相对丰度明显下降。PICRUSt 预测表明，Cd(II) 冲击负荷显著影响了氨基酸合成、核苷和核苷酸合成。本研究结果有助于采取充分的预防措施，减少废水处理系统中生物反应器性能受到的不利影响。
