进水碳磷比对连续流反硝化除磷工艺脱氮除磷效果的影响

Effect of COD-to-phosphorus ratio on performance of continuous-flow two-sludge process

针对连续流双污泥反硝化除磷工艺,考察进水碳磷质量比(m(C)/m(P))对化学需氧量(COD)、氨氮和总磷(TP)去除效果的影响.系统进水COD和氨氮分别保持在250和45 mg/L左右,通过改变进水TP浓度来调整m(C)/m(P).实验结果表明:在m(C)/m(P)比分别为64.1,42.0,33.0和17.8的情况下,TP去除率分别为93.2%,92.0%,78.3%和65.8%,除磷效率明显降低.在m(C)/m(P)>42.0的情况下,出水TP低于0.5 mg/L.随着m(C)/m(P)的降低,反硝化聚磷污泥释磷量和净聚磷量增加,净聚磷量分别为3.63,5.33,6.26和10.3mg/L.m(C)/m(P)减小有利于提高生物除磷系统的稳定性,但出水磷浓度会有所增加,可通过适当延长后置曝气池停留时间来降低出水磷浓度.m(C)/m(P)对COD的去除和脱氮的效果影响不大,COD去除率保持在85.6%～93.1%,氨氮的去除率大于93%.

The effect of COD（chemical oxygen demand）-to-phosphorus ratio（m（C）/m（P）） was investigated in a continuous-flow two-sludge process.The influent concentrations of COD and ammonia were maintained at about 250 and 45 mg/L respectively.The ratio was adjusted by the TP（total phosphorus） concentration.The results show that when the m（C）/m（P） are 64.1,42.0,33.0 and 17.8,the TP removal efficiencies are 93.2%,92.0%,78.3% and 65.8% respectively.Decreasing of ratio results in low removal efficiency obviously.When the ratio is more than 42.0,the effluent TP concentration is less than 0.5 mg/L.However,as the ratio decrease the phosphorus release amount and net phosphorus uptake amount would increase.The net phosphorus uptake amounts may get 3.63,5.33,6.26 and 10.3 mg/L when the m（C）/m（P） are 64.1,42.0,33.0 and 17.8.The decrease of m（C）/m（P）benefits the stability of the biological system but the effluent TP concentration may increase.This could be reduced by extending hydraulic retention time in the posted anaerobic tank.There is no remarkable effect of m（C）/m（P）on COD and TN（total nitrogen）removal efficiencies.The COD removal efficiency keeps at 85.6% to 93.1% and ammonia removal efficiency is more than 93%.