Abstract：
At present, eutrophication is increasingly serious, so it is necessary to effectively reduce nitrogen and phosphorus in water bodies. In this study, a pyrite/polycaprolactone-based mixotrophic denitrification (PPMD) system using pyrite and polycaprolactone (PCL) as electron donors was developed and compared with pyrite-based autotrophic denitrification (PAD) system and PCL-based heterotrophic denitrification (PHD) system through continuous flow experiment. The removal efficiency of NO3--N (NRE) and PO43--P (PRE) and the contribution proportion of PAD in the PPMD system were significantly increased by prolonging hydraulic retention time (HRT, from 1 to 48 h). When HRT was equal to 24 h, the PPMD system conformed to the zero-order kinetic model, so NRE and PRE were mainly limited by the PAD process. When HRT was equal to 48 h, the PPMD system met the first-order kinetic model with NRE and PRE reaching 98.9 ± 1.1% and 91.8 ± 4.5%, respectively. When HRT = 48 h, the NRE and PRE by PAD system were 82.7 ± 9.1% and 88.5 ± 4.7%, respectively, but the effluent SO42- concentration was as high as 152.1 ± 13.7 mg/L (the influent SO42- concentration was 49.2 ± 3.3 mg/L); the NRE by PHD system was 98.5 ± 1.7%, but the PO43--P could not be removed ideally. The concentrations of NO3--N, total nitrogen, PO43--P, and SO42- in the PPMD system also showed distinct changes along the reactor column. In addition, the microbial diversity analysis showed that prolonging HRT (from 24 to 48 h) increased the abundance of autotrophic denitrifying microorganisms in the PPMD system, ultimately increasing the contribution proportion of PAD.
摘要：
目前,富营养化日益严重，因此有必要有效减少水体中的氮和磷。在这项研究中,开发了以黄铁矿和聚己内酯（PCL）为电子供体的基于黄铁矿/聚己内酯的混合营养反硝化（PPMD）系统，并通过连续流实验与基于黄铁矿的自养反硝化（PAD）系统和基于PCL的异养反硝化（PHD）系统进行了比较。延长水力停留时间（HRT，从1到48小时)。当HRT等于24小时时，PPMD系统符合零级动力学模型，因此，NRE和PRE主要受到PAD过程的限制。当HRT等于48小时时，PPMD系统满足一级动力学模型，NRE和PRE分别达到98.9±1.1%和91.8±4.5%，分别。当HRT=48h时，PAD系统的NRE和PRE分别为82.7±9.1％和88.5±4.7％，分别,但出水SO42-浓度高达152.1±13.7mg/L（进水SO42-浓度为49.2±3.3mg/L）；PHD系统的NRE为98.5±1.7％，但PO43--P不能理想地删除。NO3--N的浓度,总氮,PO43--P,PPMD系统中的SO42-也显示出沿着反应器塔的明显变化。此外,微生物多样性分析表明，延长HRT（从24到48h）增加了PPMD系统中自养反硝化微生物的丰度，最终提高PAD的贡献比例。
