强化除磷曝气生物滤池反冲洗优化及其污泥特性

为探讨BAF(曝气生物滤池)最佳反冲洗强度及其选择依据,以某处理石化二级出水的强化除磷BAF为研究对象,采取不同的反冲洗强度进行气-水联合反冲洗,探讨反冲洗过程中出水污泥量峰值出现时间、污泥的SOUR(比好氧呼吸速率)变化、反冲洗前后微生物量和微生物脱氢酶活性(DHA)的变化以及反冲洗后的恢复效果,并对反冲洗强度参数的选择进行了优化. 结果表明:在该研究条件下,采用气洗〔强度为12 L/(m2·s)〕4 min,气-水联合洗〔气洗强度为12 L/(m2·s),水洗强度为6 L/(m2·s)〕5 min,最后用清水漂洗9 min的反冲洗方式,排水中污泥的ρ(SS)可在最短时间(3 min)达到峰值；反冲洗排水中污泥的SOUR较低,平均值为0.5 mg/(mg·h)；距离底端进水口1.3和2.2 m处的滤料层微生物的量损失较小,分别为4.4%和5.3%,其相应微生物的活性有所增加. 研究显示,该条件下反冲洗可有效清除滤料颗粒间所截留及滤料表面脱落的老化生物膜,并可保留适量活性较高的生物膜,强化了传质条件,反冲洗后对污染物的处理能力能恢复迅速. 

Optimization of Backwashing Conditions and Sludge Characteristics in Enhanced Phosphorus Removal Biological Aerated Filter

Abstract: An enhanced phosphorus removal biological aerated filter (BAF) treating petrochemical secondary effluent was used to investigate the optimized backwashing conditions. The optimized results can be used as the selection basis of backwashing BAF. The treated effluent of BAF was used as the backwashing influent, and the air-water combined backwashing mode was used. The selection of optimized backwashing conditions was based on the sludge concentration peak time of the backwashed effluent, specific oxygen uptake rate (SOUR) of the backwashed sludge, changes of the biomass and microbial activity, and the recovery of the BAF performance. The results showed that a water intensity of 6 L/(m²·s) and gas washing intensity of 12 L/(m²·s) were the optimized backwashing parameters. The best backwashing mode was:The best backwashing mode was:air backwash (air washing intensity 12 L/(m²·s)) for 4 min, air and water combined backwash (air washing intensity 12 L/(m²·s), water washing intensity 6 L/(m²·s)) for 5 min and rinse with water for 9 min. On these conditions, the sludge concentration peak of backwashed effluent had the shortest time of 3 min. The SOUR of the sludge in the backwashed effluent was relatively low, with an average value of 0.5 mg/(mg·h). The loss of sludge at the heights of 130 cm and 220 cm of the BAF were only 4.4% and 5.3%, respectively. However, the microbial activity measured by dehydrogenase activity increased slightly. Under the conditions, the particles trapped between the filter surface and the aging biofilm could be effectively removed. In addition, the active biofilm remained with the increasing mass transfer. The recovery of the BAF performance was very quick, and the ability to deal with pollutant removal could be recovered quickly after the backwashing. Thus, the optimized backwashing conditions of the reactor were determined.