A/O生物膜法强化处理石化废水及生物膜种群结构研究

采用A/O生物膜反应器处理石化综合废水.反应器在O段添加装有改性聚氨酯泡沫的多孔塑料球载体,强化有机物的降解效率.反应器进水分别为水解酸化池出水(阶段I),石化工业废水与生活污水比例为3:1(阶段II)以及单纯的石化工业废水(阶段III). 结果表明,尽管进水COD和氨氮波动较大,但出水COD和氨氮的去除率保持稳定,说明生物膜反应器具有较好的抗冲击负荷能力.在HRT为30h, COD和氨氮的去除率为74%~77%和96%~93%,总氮和总磷的去除率为58%和79%.第II阶段进水为工业废水和生活污水混合的处理效果最好,出水COD和氨氮浓度分别为(63±12)mg/L和(0.75±0.28)mg/L.出水总氮主要为硝酸氮,亚硝酸氮的浓度很低(小于0.1mg/L),表明硝化作用进行得较为完全.进水中有机物的分子量主要分布在小于1kDa(70.9%)和大于100kDa(10.4%).出水中大于10kDa的有机物所占比例减小,分子量主要分布在小于1kDa(56.6%)和1~5kDa(26.2%),表明A/O生物膜反应器对大分子有机物的降解较好.454高通量测序结果表明: 生物膜中变形菌门菌群所占比例最大(60.0%),其次是浮霉菌门(16.9%)和拟杆菌门(9.8%).在属的水平检测到氨氧化菌(AOB)Nitrosomonas和亚硝酸盐氧化菌(NOB) Nitrospiraceae Nitrospira以及反硝化菌Azospira和Thermomonas.NOB的比例较高,这与反应器较好的硝化作用相一致.

Enhanced treatment of petrochemical wastewater by using A/O biofilm reactor and analysis of biofilm community

An A/O biofilm reactor was developed for the treatment of petrochemical wastewater. Porous plastic spherical carriers filled with modified polyurethane foams were added in the aerobic parts to improve the degradation of organic pollutants. The A/O biofilm reactor was fed with effluent from the hydrolysis acidification tank (phase I), a mixed petrochemical and domestic wastewater with a ratio 3:1 (phase II) and petrochemical wastewater (phase III), respectively. Results showed that the removal efficiency of COD and ammonium maintained stable despite their great fluctuation in influent, indicating that the A/O biofilm reactor had a good capacity to resist the loading shock. At a hydraulic retention time of 30h, COD and ammonium removal reached 74%~77% and 96%~93%, respectively. Total nitrogen and total phosphorus removal were 58% and 79%, respectively. The performance of reactor at phase II was the best. The effluent COD and ammonium concentrations kept at (63±12)mg/L and (0.75±0.28)mg/L, respectively. Total nitrogen in the effluent existed mainly in the form of nitrate and nitrite maintained at low levels (less than 0.1mg/L), which indicated that nitrification proceeded almost completely. The molecular weight (MW) of organic matters in the influent ranged mainly in less than 1kDa (70.9%) and more than 100kDa (10.4%). In the effluent, MW of organic matters was mainly in less than 1kDa (56.6%) and 1~5kDa (26.2%). The distribution ratio of organics with a MW of higher than 10kDa decreased, indicating that A/O biofilm reactor was good at degradation of the macromolecular organics. Analysis of 454pyrosequencing showed that Proteobacteria accounted for most of sequence (60.0%), followed by Planctomycetes (16.9%) and Bacteroidetes (9.8%) at the phylum levels. At the genus levels, ammonia oxidizing bacteria (AOB) Nitrosomonas and nitrite oxidizing bacteria (NOB) Nitrospiraceae Nitrospira and denitrifier Azospira and Thermomonas were identified. NOB were highly enriched which was consistent with the good nitrification.