Abstract：
Biological denitrification is still the most important pathway to purifying nitrate-containing wastewater. In this study, pyrite (FeS2 ) and polycaprolactone (PCL) were used as electron donors to construct sole or combined denitrification systems, that is, pyrite-based autotrophic denitrification (PAD) system, PCL-supported heterotrophic denitrification (PHD) system, and split-mixotrophic denitrification system (combined PAD + PHD), all of which were operated under five different hydraulic retention times (HRTs) for 150 days. The results showed that the removal rates (RE) of nitrate (NO3 - -N) and inorganic phosphorus (PO4 3- -P) by PAD were 91% and 94%, respectively, but the effluent sulfate (SO4 2- ) concentration was as high as 168.2 mg/L; the removal rate of NO3 - -N by PHD was higher than 99%, but the PO4 3- -P could not be removed ideally; the removal rates of NO3 - -N and PO4 3- -P by PAD + PHD were higher than 95% and 99%, respectively, and the effluent SO4 2- concentration was only 7.2 mg/L. Through the analysis of the surface scanning electron microscope (SEM) images of the two kinds of media before and after use, it was found that the coupled mode of PAD + PHD was more favorable for biofilm formation than the sole PAD or PHD process, and the microorganisms in the PAD + PHD mode made more full use of electron donors. Moreover, the biomass of the PAD + PHD mode was lower than that of the PAD or PHD process, but the denitrification efficiency of the coupled mode was more efficient, indicating that the functional microorganisms in the PAD + PHD mode might have a certain synergistic effect. PRACTITIONER POINTS: Removal rates of NO3 -, PO4 3 -, and SO4 2 - by PAD were 91%, 94%, and -233%, respectively. Removal rate of NO3 - by PHD exceeded 99%, but PO4 3 - could not be removed ideally. Removal rates of NO3 -, PO4 3 -, and SO4 2 - by PAD + PHD were 95%, 99%, and 86%, respectively. The coupled mode was more favorable for biofilm formation than the sole PAD or PHD. The coupled mode had lower biomass but got more excellent denitrification efficiency.
摘要：
生物反硝化仍然是净化含硝酸盐废水的最重要途径。在这项研究中,黄铁矿（FeS2）和聚己内酯（PCL）被用作电子供体来构建单独或组合的反硝化系统，也就是说,黄铁矿型自养反硝化(PAD)系统,PCL支持的异养反硝化（PHD）系统，和分体式混养反硝化系统(PAD+PHD组合)，所有这些都在五个不同的液压保留时间（HRT）下操作150天。结果表明,PAD对硝酸盐(NO3--N)和无机磷(PO4--P)的去除率分别为91%和94%,分别,但出水硫酸盐(SO42-)浓度高达168.2mg/L；PHD对NO3--N的去除率高于99%，但PO43--P不能理想地去除；PAD+PHD对NO3--N和PO43--P的去除率分别高于95%和99%，分别,出水SO42-浓度仅为7.2mg/L通过对两种介质使用前后的表面扫描电子显微镜(SEM)图像的分析,发现PAD+PHD的耦合模式比单独的PAD或PHD过程更有利于生物膜的形成，PAD+PHD模式下的微生物更充分地利用了电子供体。此外，PAD+PHD模式的生物量低于PAD或PHD过程的生物量，但是耦合模式的反硝化效率更高，表明PAD+PHD模式下的功能性微生物可能具有一定的协同作用。PRACTIONERPOINTS:NO3-,PO43-,PAD的SO42-为91%，94%,和-233%，分别。PHD对NO3-的去除率超过99%，但PO43-不能理想地删除。NO3-的去除率PO43-,和SO42-PAD+PHD为95%，99%,86%,分别。耦合模式比单独的PAD或PHD更有利于生物膜形成。耦合模式具有较低的生物量，但具有更好的反硝化效率。
