不同填料在折流湿地中脱氮除磷的动力学分析

为了解决我国西部农村分散式生活污水污染问题,结合西北地区年平均气温条件特征,基于潜流湿地原理对比研究了混凝土渣、砾石和生物炭脱氮除磷效应,分析其对污染物的降解作用。结果表明：随着水力停留时间(HRT)的延长,污染物含量明显降低,湿地最佳HRT均为2.5 d,3种填料湿地对化学需要量(COD)、氨氮(${ {\rm{NH}}_{\rm{4}}^{\rm{ + }}}$-N)、磷酸盐(${ {\rm{PO}}_{\rm{4}}^{{\rm{3 - }}}}$-P)的去除效果差异性显著(P<0.01);混凝土渣对污水中${ {\rm{PO}}_{\rm{4}}^{{\rm{3 - }}}}$-P的去除最优,去除率为97.11%;生物炭综合处理能力较强,COD、${ {\rm{NH}}_{\rm{4}}^{\rm{ + }}}$-N、悬浮物(SS)的去除率达到了90.51%、72.38%、94.57%;生物炭作为优选湿地填料还具有较快的污染物降解速率特征,且有机污染物和磷酸盐的生化降解过程符合一级反应动力学模型,R²在0.9以上。因此,生物炭作为湿地填料具有良好的应用价值,对解决西北地区农村水污染问题具有重要的意义。

Kinetic analysis of nitrogen and phosphorus removal by different fillers in a baffled wetland

In order to solve the pollution problem of decentralized domestic sewage in the rural area of western China, in combination with the characteristics of annual mean temperature in Northwest China, this study compared the nitrogen and phosphorus removal effects of concrete slag, gravel and biochar based on the principle of subsurface flow wetland(SFW), and the pollutants degradation effect of SFW was also analyzed. The results showed that with the increase of hydraulic retention time (HRT), the pollutant concentration decreased significantly, and the optimum HRT of the wetland was 2.5 d. The differences in the removal of chemical oxygen demand (COD), ammonia nitrogen ($ {\rm{NH}}_{\rm{4}}^{\rm{ + }}$-N), and phosphorus ($ {\rm{PO}}_{\rm{4}}^{{\rm{3 - }}}$-P) among three kinds of fillers were very significant (P<0.01), of which the $ {\rm{PO}}_{\rm{4}}^{{\rm{3 - }}}$-P removal from sewage by concrete slag was the highest with the removal rate of 97.11%. Biochar had the strongest comprehensive treatment ability, its removal rates for COD, $ {\rm{NH}}_{\rm{4}}^{\rm{ + }}$-N and suspended matter (SS) were 90.51%, 72.38% and 94.57%, respectively, as the optimal wetland filler, it also showed the fast degradation rate of pollutants, and the corresponding biochemical degradation process of organic contaminant and phosphate accorded with the first-order reaction kinetics model with R2 above 0.9. Therefore, biochar has good application value when it is taken as the wetland filler, and is of great significance to solve rural water pollution questions in Northwest China.