生物滞留系统处理水产养殖尾水的效能和机制

为探究生物滞留系统(bioretention system，BS)对水产养殖尾水的处理效能，设计并构建倒置(inverted bioretention system，IBS)和正置(control bioretention system，CBS)2组生物滞留系统，在不同进水条件下比较了2种BS构建方式的运行效能，通过胞外聚合物(EPS)、三维荧光光谱和电子传递活性(ETSA)等方法阐述了不同构建方式下BS的脱氮机制。结果表明：在不同进水条件下IBS的处理效能优于CBS，当运行间隔周期为1 d时，IBS的TN和NO₃⁻-N去除率分别达到71.79%~82.00%和68.70%~85.84%，平均去除率比CBS分别高出10.65%和15.89%。CBS和IBS的TN和NO₃⁻-N去除率随进水负荷的增加呈先升高后稳定的趋势，TP波动最小，去除率均稳定在97.04%~99.22%。构建方式对EPS的组分无明显影响，但对EPS含量和ETSA影响显著。IBS的构建方式可促进微生物分泌更多的EPS，其中EPS的多糖(PS)和蛋白质(PN)含量分别比CBS高出66.89 ug·g⁻¹和603.24 ug·g⁻¹，并且IBS的酪氨酸、色氨酸和微生物代谢产物明显高于CBS；此外，与CBS的ETSA为(0.47±0.07) ug·(g·min)⁻¹，相比IBS提高了0.35 ug·(g·min)⁻¹。以上研究结果为应用生物滞留系统技术处理养殖尾水提供参考。

Efficiency and mechanism of bioretention systems for aquaculture wastewater treatment

In order to explore the treatment efficiency of aquaculture wastewater by bioretention system(BS), two groups of the inverted bioretention system(IBS) and control bioretention system(CBS) were designed and constructed, and their efficiency was compared under different influent conditions. The denitrification mechanism of BS under different construction methods was analyzed through extracellular polymer(EPS), three-dimensional fluorescence spectroscopy and electron transport activity(ETSA). The results showed that the treatment efficiency of IBS was better than that of CBS under different influent conditions. When running interval period was 1d, the TN and NO3-N removal rates of IBS reached 71.79%~82.00% and 68.70%~85.84%, respectively, and the average removal rates were 10.65% and 15.89% higher than those of CBS, respectively. The TN and NO3-N removal rates of CBS and IBS increased first and then stabilized with the increase of influent load, while TP fluctuated slightly, and the removal rate was stable at 97.04%~99.22%. The construction method had no significant effect on the composition of EPS, but had a significant effect on EPS content and ETSA. The construction of IBS could promote more EPS secretion by the microbial, of which the polysaccharide(PS) and protein(PN) contents in EPS were 66.89 ug·g−1 and 603.24 ug·g−1 higher than CBS, respectively, and the tyrosine, tryptophan and microbial metabolites of IBS were significantly higher than CBS. In addition, IBS improved by 0.35 ug·(g·min)−1 compared to CBS's ETSA of (0.47±0.07) ug·(g·min)−1. The results provide a theoretical reference for the application of bioretention system technology to treat aquaculture wastewater.