饥饿对两级SBR反应器内活性污泥的影响

Impact of Starvation Conditions on Activated Sludge in Two-Stage SBR Reactor

为探究饥饿期内活性污泥中微生物活性的衰减速率、物理性质的变化及恢复情况,研究了好氧[ρ(DO)=5.50 mg/L]/缺氧[ρ(DO)≤0.03 mg/L]饥饿期对稳定运行的两级SBR反应器内污泥活性的影响,同时考察了污泥的恢复能力及理化性质的变化.结果表明:30 d的饥饿使COD_(Cr)去除率下降了20.8%,r_(COD)(异养菌活性)由111.8 mg/(L·h)降至59.2 mg/(L·h);NH_4^+-N去除率下降了59.2%;COD_(Cr)去除率、r_(COD)、NH_4^+-N去除率分别在94、97、95 d时恢复.饥饿期内AOB(氨氧化细菌)的衰减速率(k_(AOB))为0.029 d^(-1),NOB(亚硝酸盐氧化细菌)的衰减速率(k_(NOB))为0.021 d^(-1).恢复初期AOB的恢复速率(k_(AOB)'=0.125 d^(-1))大于NOB的恢复速率(k_(NOB)'=0.069 d^(-1)),导致NO_2^--N的累积.此外,饥饿期ρ(MLSS)下降了42.6%;SVI(污泥指数)由71.2mL/g升至135.1 mL/g;w(EPS)(EPS为胞外聚合物)由37.9 mg/g(以VSS计)降至18.5 mg/g,其中主要由w(PN)(PN为蛋白质)的减少所致;各物理指标的变化均可在恢复期内恢复.

In order to study microbial activity decay rates and physical property changes in activated sludge during a starvation period,as well as the recovery after restarting,this paper studied the impact of alternating aerobic（ρ（DO） =5.50 mg/L） /anoxic（ρ（DO） ≤0.03mg/L） starvation conditions on sludge activity in a two-stage sequencing batch reactor（SBR） under stable operation.Changes of the recovery ability and the physical and chemical properties of the sludge were also researched.It was shown in the results that after a starvation period of 30 d,the COD_（Cr） removal rate decreased by 20.8%,heterotrophic bacterial activity（r_（COD）） decreased from 111.8mg/（L·h） to 59.2 mg/（L·h）,and the NH_4^＋-N removal rate decreased by 59.2%.In addition,they were recovered at the 94^（th） day,97^（th） day and 95^（th） day,respectively.The decay rate of ammonia oxidizing bacteria（AOB）（k_（AOB）） was 0.029 d^（-1）.The decay rate of nitrite oxidizing bacteria（NOB）（k_（NOB）） was 0.021 d^（-1）.In the earlier stage of recovery,the recovery rate of AOB（k_（AOB）＇ =0.125 d^（-1）） was higher than that of NOB（k_（NOB）＇ = 0.069 d^（-1））,which led to accumulation of NO_2^--N.In addition,due to the starvation period,the sludge concentration（MLSS） decreased by 42.6%,the sludge index（SVI） increased from 71.2 mL/g to 135.1 mL/g,and the concentration of extracellular polymeric substances（w（EPS） expressed by VSS） decreased from 37.9 mg/g to 18.5 mg/g,which mainly referred to the decrease in protein content.Changes of the physical parameters could be recovered in the recovery period.