Liu Yi, Wang Hualin, Xu Yinxiang, Tu Qingsong, Chen Xiurong
National Engineering Laboratory for Industrial Wastewater Treatment, East China University of Science and Technology, Shanghai, 200237, China.
National Engineering Laboratory for Industrial Wastewater Treatment, East China University of Science and Technology, Shanghai, 200237, China.
Chemosphere. 2017 Dec;189:206-212. doi: 10.1016/j.chemosphere.2017.09.056. Epub 2017 Sep 12.
This work presents the novel application of hydrocyclones for mixed liquor recirculation (MLR) treatment in the anoxic/aerobic (A/O) process to enhance the denitrification process. An exhaustive investigation on treated activated sludge and A/O effluents was conducted in batch and continuous operation tests. The median diameter of the sludge flocs was decreased from 78.82 μm to 15.77-23.31 μm, and the extracellular polymeric substances (EPS) desorption was observed, thus leading to the release of the soluble chemical oxygen demand (SCOD). A marked increase in the BOD/TN ratio was consequently achieved, which supplied the carbon source and improved the biodegradability of the MLR. The hydrocyclone treatment also enabled a 7.17% ± 0.93% specific oxygen utilization rate (SOUR) increase at the optimal hydrocyclone intensity of 0.13 MPa, owing to the desorption of positioned microbial secretion from the microorganism cells. The nitrate reductase and nitrite reductase were also improved by 15.13% ± 1.16% and 17.61% ± 1.55%, respectively. The nitrate removal efficiency was enhanced by 13.6%, and the nitrogen oxide gases varied slightly; this behavior was consistent with the variations in the key enzymes involved in denitrification. The A/O process operated in the mode of hydrocyclone-treated MLR, compared with in the conventional mode, resulted in a 15.56% higher TN removal, and the other effluent parameters remained stable. Hydrocyclone disruption is thus a convenient and energy-efficient process with broad implications in denitrification development.
本研究介绍了水力旋流器在缺氧/好氧（A/O）工艺中用于混合液回流（MLR）处理以强化反硝化过程的新应用。在间歇和连续运行试验中，对处理后的活性污泥和A/O出水进行了详尽研究。污泥絮体的中位直径从78.82μm降至15.77 - 23.31μm，同时观察到胞外聚合物（EPS）解吸，从而导致溶解性化学需氧量（SCOD）的释放。进而显著提高了BOD/TN比，为MLR提供了碳源并改善了其生物降解性。由于定位微生物分泌物从微生物细胞上解吸，在0.13MPa的最佳水力旋流器强度下，水力旋流器处理还使比氧利用率（SOUR）提高了7.17%±0.93%。硝酸盐还原酶和亚硝酸盐还原酶也分别提高了15.13%±1.16%和17.61%±1.55%。硝酸盐去除效率提高了13.6%，氮氧化物气体变化不大；这种行为与反硝化过程中关键酶的变化一致。与传统模式相比，以水力旋流器处理的MLR模式运行的A/O工艺，总氮去除率提高了15.56%，且其他出水参数保持稳定。因此，水力旋流器破碎是一种便捷且节能的工艺，在反硝化发展方面具有广泛的意义。
