Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil.
Department of Civil Construction, Federal Institute of Education, Science and Technology of Ceará, Fortaleza, Ceará, Brazil.
Environ Res. 2021 Jul;198:111313. doi: 10.1016/j.envres.2021.111313. Epub 2021 May 12.
This work assessed the effect of increasing microaeration flow rates (1-6 mL min at 28 °C and 1 atm, equivalent to 0.025-0.152 L O L feed) on the removal/biotransformation of seven organic micropollutants (OMPs) (three hormones, one xenoestrogen, and three pharmaceuticals), at 200 μg L each, in a lab-scale upflow anaerobic sludge blanket reactor operated at a hydraulic retention time (HRT) of 7.4 h. Additionally, the operational stability of the system and the evolution of its microbial community under microaerobic conditions were evaluated. Microaeration was demonstrated to be an effective strategy to improve the limited removal/biotransformation of the evaluated OMPs in short-HRT anaerobic wastewater treatment systems. The rise in the airflow rate considerably increased the removal efficiencies of all OMPs. However, there seems to be a saturation limit for the biochemical reactions. Then, the best results were obtained with 4 mL air min (0.101 L O L feed) (~90%) because, above this flow rate, the efficiency increase was negligible. The long-term exposure to microaerobic conditions (249 days) led the microbiota to a gradual evolution. Consequently, there was some enrichment with species potentially associated with the biotransformation of OMPs, which may explain the better performance at the end of the microaerobic term even with the lowest airflow rate tested.
本研究评估了在 28°C 和 1 个大气压下增加微曝气流速（1-6 mL min，相当于 0.025-0.152 L O2 进料）对七种有机微污染物（OMPs）（三种激素、一种外源性雌激素和三种药物）的去除/生物转化的影响，每种污染物的浓度为 200μg/L，在水力停留时间（HRT）为 7.4 h 的实验室规模上流式厌氧污泥床反应器中进行。此外，还评估了系统在微氧条件下的运行稳定性和微生物群落的演变。微曝气被证明是一种有效的策略，可以提高短 HRT 厌氧废水处理系统中评估的 OMPs 的有限去除/生物转化效率。曝气率的提高显著提高了所有 OMPs 的去除效率。然而，生化反应似乎存在饱和限制。然后，以 4 mL min 的空气流量（0.101 L O2 进料）获得了最佳结果（约 90%），因为在该流速以上，效率的提高可忽略不计。长期暴露于微氧条件（249 天）导致微生物群逐渐演变。因此，某些物种可能与 OMPs 的生物转化有关，这可能解释了为什么在微氧期结束时，即使使用测试的最低空气流量，性能也更好。
