新型强化生态砾石床应用于污水厂尾水脱氮除磷效能

Study on the efficiency of denitrification and phosphorus removal from the effluent of wastewater treatment plants by novel enhanced ecological gravel beds

    摘要
  • 摘要: 针对常规生态砾石床处理污水厂尾水时碳源不足限制其反硝化效能的问题，制备了碱改性玉米芯（CC-AL）强化脱氮填料，与钢渣强化除磷填料一起构建新型强化生态砾石床，以无强化脱氮除磷填料的生态砾石床（CG组）作为对照，研究填料种类和水力停留时间（HRT）对砾石床处理实际污水厂尾水氮磷去除效能的影响，并采用宏基因组分析微生物群落特征和氮代谢过程中酶的相对丰度。结果表明：CC-AL比未改性玉米芯（CC-UN）具有更好的释碳能力，CC-AL生态砾石床（CC-AL组）脱氮除磷效能优于CC-UN生态砾石床（CC-UN组）。HRT为6 h时CC-AL组对尾水中TN、\mathrmNO_3^- -N和TP去除率分别为64.72%±4.20%、85.93%±2.18%和31.32%±1.25%；随着HRT的降低（由6 h降为2 h），TN和\mathrmNO_3^- -N的去除率逐渐降低，但当HRT为4 h时，TP去除率最高，为40.08%±2.30%。CC-AL和CC-UN通过强化反硝化途径提高了生态砾石床的脱氮效能，增加了反硝化细菌相关类群Bacteroidota、Thermodesulfobacteriota等的相对丰度和反硝化还原酶的浓度，CC-AL组硝酸盐还原酶EC 1.7.99.-和EC 1.7.5.1分别是CG组的2.10倍和2.35倍。当HRT为6 h时，CC-AL组对TN和TP的表面负荷削减率高达5.29 g/(m2·d)（以N计）和0.31 g/(m2·d)（以P计），具有较高氮磷去除效能和应用潜力。综合考虑氮磷去除效能，生态砾石床优选填料为CC-AL，优选HRT为6 h。

     

    Abstract: To avoid the influence of insufficient carbon sources on the denitrification of conventional ecological gravel beds (EGBs) during the treatment of wastewater treatment plant (WWTP) effluent, alkali-modified corncobs (CC-AL) as enhanced nitrogen removal fillers and steel slag as enhanced phosphorus removal fillers were prepared to set up the novel enhanced EGBs, and the influence of filler types and hydraulic retention time (HRT) on the nitrogen and phosphorus removal was studied compared with the EGB without enhanced nitrogen and phosphorus removal fillers, i.e. control group EGB. The characteristics of the microbial community and the relative abundance of enzymes involved in the nitrogen metabolism were analyzed by metagenomics. The results indicated that CC-AL had better carbon release capacity than the unmodified corncob (CC-UN), and the nitrogen and phosphorus removal efficiencies of the CC-AL EGB were higher than those of the CC-UN EGB. The TN, \mathrmNO_3^- -N, and TP removal efficiencies of CC-AL EGB at 6 h HRT were 64.72%±4.20%, 85.93%±2.18%, and 31.32%±1.25%, respectively. As HRT decreased (from 6 h to 2 h), the removal rates of TN and \mathrmNO_3^- -N decreased gradually, and the highest TP removal efficiency (40.08%±2.30%) was achieved at 4 h HRT. Both CC-AL and CC-UN could improve the nitrogen removal efficiency through the enhancement of denitrification, which increased the concentration of denitrification reductases and the relative abundance of denitrifying bacteria-related groups such as Bacteroidota and Thermodesulfobacteriota. The concentrations of nitrate reductases EC 1.7.99.- and EC 1.7.5.1 in CC-AL EGB were 2.10 and 2.35 times higher than those of the CG-EGB. At 6 h HRT, the TN and TP surface load reduction rates of the CC-AL EGB were 5.29 g/(m2·d) (as N) and 0.31 g/(m2·d) (as P), which were relatively high and indicated potential practical application. Based on the comprehensive consideration of the nitrogen and phosphorus removal, CC-AL and 6 h were recommended as the optimal filler and HRT for EGBs.

     

    • HTML全文
    • 参考文献(46)
    • 相关文章
    • 施引文献
  • 资源附件(0)

/

返回文章
返回