沸石生物滤池处理低浓度生活污水的工艺性能及影响因素

为将电厂低浓度生活污水处理后回用于循环冷却水,开发了沸石滤料曝气生物滤池(ZBAF)工艺,在直径0.2m、滤料高3m的ZBAF装置中处理低浓度生活污水.结果表明,在温度为12℃～17℃,停留时间1.4h,气水比4:1,进水浊度、BOD₅、COD_Cr和NH₄⁺-N分别为59NTU、30mg/L、81mg/L和16mg/L时,相应的出水指标为3.2NTU、3.2mg/L、14.5mg/L和0.5mg/L,满足再生水用作循环冷却补充水的水质标准.改变水力停留时间和气水比对BOD₅、COD_Cr和浊度去除率影响不大,但对NH₄⁺-N去除率影响较大.生物相观察发现:反应器内脱碳/硝化区(C/N区)生物相很丰富,其中固着型纤毛虫很多;而硝化区(N区)生物相比较单一,主要为硝化菌.固着型纤毛虫数量明显减少处为2个区的分界线.

Performance and Its Influencing Factors of a Zeolite Biofilter for Dilute Domestic Wastewater Treatment

To reuse dilute domestic wastewater in power plant region as the makeup of recirculating cooling water, a renovate reactor--zeolite media biological aerated filter (ZBAF) was developed. A pilot scale ZBAF of 0.2 m in diameter and 3 m in media height was tested to treat dilute domestic wastewater. The results showed that turbidity, BOD5, CODcr and NH4(+)-N in effluent was 3.2 NTU, 3.2 mg/L, 14.5 mg/L and 0.5 mg/L when the corresponding influent concentration was 59 NTU, 30 mg/L, 81 mg/L and 16 mg/L, respectively, under the conditions of t = 12 degrees C-17 degrees C, HRT = 1.4 h and gas/liquid = 4:1. The effluent quality met the water quality standards of the treated water reused for cooling water makeup. The removal rate of BOD5, COD and turbidity did not change much with the change of HRT and the ratio of gas to liquid, but NH4(+)-N removal rate changed greatly. The parameters along the depth of ZBAF showed that the biofilm phase was abundant in carbon-oxidation/nitrification(C/N) zone and simplex in nitrification (N) zone. Ciliate was plentiful in C/N zone. Biofilm in N zone was mainly consists of nitrifiers. The point that the number of ciliate decreased apparently was the boundary of the two zones.