不同C/N下BBFR-IVCW耦合工艺对微污染水体脱氮效果

Nitrogen removal of BBFR-IVCW system treating micro-polluted water under different C/N ratios

以生物质生物膜反应器(biomass bio-film reactor,BBFR)和复合垂直流人工湿地(integrated vertical-flow con-structed wetland,IVCW)构成的组合系统来处理高氮寡碳微污染地表水,考察不同C/N比对组合系统脱氮效果的影响。实验结果表明,2#CW(2#湿地系统)的TN出水均值低于CW1#(1#湿地系统),出水达到地表水环境质量Ⅳ级标准。C/N比对BBF系统的TN去除率有很大影响,而C/N比对硝酸盐氮去除率的影响并不明显。综合从碳源投加的经济成本因素和系统的反硝化效果来看,最优的C/N比为4.9。C/N=2.8时,1#CW对NO3--N的去除率最高,为(71.88±15.70)%,并且与C/N>2.8的几组情况有显著性差异(F3,56=21,p<0.05)。在C/N=4.1时,2#CW对NO3--N的去除率为(92.83±11.26)%,与其他C/N比值下NO3--N的去除率差异显著(F3,56=4.34,p<0.05)。C/N比的变化对出水剩余TN、NO3--N的影响情况比较一致。1#CW中出水TN和NO3--N浓度都是随着C/N比的增大而逐步增加;而2#CW中出水TN和NO3--N浓度都是随着C/N比的增大先减小,在C/N>4.1时又有所增加。BBFR系统对COD的去除高于其对TN去除的贡献率。

In this experiment,high nitrogen-low carbon micro-polluted surface water was treated by the combination of bio-film reactor（BBFR） and integrated vertical-flow constructed wetland（IVCW） and the effects of different C/N on nitrogen removal were also investigated.Results indicated that the mean effluent concentration of TN in 2#CW（2# wetland system） was lower than 1#CW and met surface water environmental quality standards Grade Ⅳ standard.The C/N ratio has great influence on TN removal of the BBFR system,but has no obvious influence on nitrate removal.The optimal C/N ratio in this experiment was 4.9 considering of the economic cost factor of carbon added and the system de-nitrification effect.At C/N=2.8,NO3--N removal rate of 1#CW（71.88 ±15.70）% was significantly higher than others which their C/N ratios were greater than 2.8（F3,56 = 21,p0.05）.At C/N=4.1,NO3--N removal rate of 2#CW was（92.83±11.26）%,which was significantly different from other C/N ratios（F3,56 = 4.34,p0.05）.The impact of C/N changes on TN of effluent was in accordance with that of NO3--N.With the increasing of C/N in 1#CW,the concentration of effluent TN and NO3--N rose;2#CW showed the opposite when C/N was less than 4.1.BBFR showed higher contribution to the combined system in terms of removing COD comparing with TN.