聚己内酯与陶粒系统强化反硝化研究

Enhanced Denitrification Performance by Addition of Polycaprolactone and Ceramsite

摘要:

以聚己内酯（PCL）和陶粒分别为固体碳源与生物膜载体，首先研究了PCL在湖水微生物与非生物作用下的释碳效果，并分析了其对反硝化脱氮的作用；其次考察了PCL与陶粒共混条件下的基于微生物固定化作用的反硝化增强效果。结果表明：在非生物条件下，PCL在前24 h内静态水解释碳速率（0.656 mg/（g·d））较快，之后进入稳定释碳阶段，其后期稳定释碳速率为0.095 mg/（g·d）。在湖水微生物作用下，PCL的稳定释碳速率（0.286 mg/（g·d））远高于非生物条件下静态实验平均释碳速率（0.123 mg/（g·d）），为后者的2.33倍，说明生物过程能够显著提高PCL中溶解性有机碳（DOC）的释放。在PCL作为固体碳源的反硝化系统中分别加入20%、50%和100%陶粒可以实现其稳定反硝化速率由原来的0.813 mg/（L·h）（空白组，不添加陶粒）上升为0.894 mg/（L·h）、1.015 mg/（L·h）和1.056 mg/（L·h），表明陶粒的添加可以进一步强化系统的反硝化效果。对反应过程指标进行考察表明，系统不存在NO2--N的累积，但是可溶性微生物产物（SMP）具有上升趋势。

Abstract:

Polycaprolactone（PCL） and ceramsite were used as the solid denitrification carbon source and biofilm carrier respectively for the efficiency enhancement of denitrification. The performance of dissolved organic carbon（DOC） releasing of PCL as well as its roles in the denitrification process was investigated under microbial and amicrobic condition. Further research about the effect of ceramsite addition on denitrification efficiency was carried out by blending PCL with different dosages of ceramsite. Results showed that the DOC releasing rate was fast in the initial period（24 h） with the value of 0.656 mg/（g·d），then became slow and stable（0.095 mg/（g·d）），under amicrobic condition. However，the DOC releasing rate under microbial condition（0.286 mg/（g·d）） was much faster than those under amicrobic condition（0.123 mg/（g·d）），manifesting a 1.33 times of enhancements. This indicated that biological processes could significantly increase the efficiency of DOC release from PCL. Moreover，addition of ceramsite to PCL could improve the denitrification performance. The addition of 20，50 g and 100 g ceramsite to 100 g PCL led to the increase of denitrification rates from 0.813 mg/（L·h）（no addition） to 0.894 mg/（L·h），1.015 mg/（L·h） and 1.056 mg/（L·h），respectively. In addition，no NO2--N accumulation was observed during these processes，while a bit of soluble microbial products（SMP） accumulation was identified by Fluorescence EEM spectra.