MBBR系统同步硝化反硝化生物脱氮特性研究

为了研究同步硝化反硝化过程中的脱氮特性,采用移动床生物膜(MBBR)系统,在污水平均C/N为3.5的条件下,研究了水力停留时间(HRT)及曝气量对系统同步硝化反硝化过程中氮和有机物降解的影响,并分析了COD、NH4+-N及TN在移动床生物膜系统中的沿程变化情况。结果表明,在移动床生物膜中实现了同步硝化反硝化现象,控制HRT为14 h,曝气量为100 L.h-1,溶解氧在4.5 mg.L-1左右时,COD、NH4+-N和TN的去除率分别达到83.53%、78.51%和62.89%;随着HRT的增加,COD、NH4+-N和TN的去除率都相应提高,且NH4+-N和TN去除率增加的幅度更大;随着曝气量的减小,COD、NH4+-N和TN的去除率相应降低,且NH4+-N和TN去除率下降得更明显;NH4+-N和TN的浓度基本上是按进水、反应器和沉淀池沿程降低,且主要去除发生在反应器内,反应器内部水质和其出水水质十分相近,表明该MBBR反应器的流态是完全混合式的。

Biodenitrification characters study using simultaneous nitrification and denitrification in moving-bed biofilm reactor system

The biodenitrification characters of simultaneous nitrification and denitrification(SND) were studied. Under the condition that the average C/N ratio of influent was 3.5, the effects of hydraulic retention time(HRT) and aeration volume on the performance of denitrifieation and organic matter degradation in moving-bed biofilm reactor (MBBR) system were studied, and the changing situation of chemical oxygen demand (COD),ammonia nitrogen (NH_4~+-N) and total nitrogen (TN) along the system were analyzed. The experiment results showed that the phenom enon of simultaneous nitrification and denitrification took place in the MBBR, and the denitrification effect was sat isfactory,namely when HRT, aeration volume and dissolved oxygen (DO) were 14 h, 100 L·h~(-1) and 4. 5 mg·L~(-1), the average removal rates of COD,NH_4~+-N and TN were 83.53% ,78.51% and 62.89 % ,respectively. The removal rates of COD, NH_4~+-N and TN went up accordingly as HRT was gradually increased, but the removal rates of NH_4~+-N and TN went up even faster. The removal rates of COD, NH_4~+-N and TN brought down accordingly as aeration volume was reduced, but the removal rates of NH_4~+-N and TN brought down even faster. The concentration of NH_4~+-N and TN decreased along the way of influent, reactor and sedimentation tank basically, and the main removal was happened in the MBBR. In addition, the flow state of the MBBR was completely mixed as water quality of the reactor was similar to the influent's.