饥饿对两级SBR反应器内活性污泥的影响

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)；NH₄+-N去除率下降了59.2%；COD_Cr去除率、r_COD、NH₄+-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NO₂--N的累积. 此外,饥饿期ρ(MLSS)下降了42.6%；SVI(污泥指数)由71.2 mL/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. 

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

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)≤0.03 mg/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 111.8 mg/(L·h) to 59.2 mg/(L·h), and the NH₄+-N removal rate decreased by 59.2%. In addition, they were recovered at the 94th day, 97th day and 95th 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 NO₂--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.