一体式A/O生物接触氧化法处理生活污水回用研究

Study the Intergrated A/O Fixed Biofilm Reactor on Treatment of Domestic Wastewater for Reuse

采用一体式A/O生物接触氧化工艺处理生活污水,研究回流比和在有无回流的情况下改变气水比等因素对系统性能的影响。结果表明,在进水流量5 L/h,气水比为20∶1,进水有机负荷0.517 kg/(m3.h),回流比为3时,出水COD和氨氮分别为8.86 mg/L和4.32 mg/L,达到城市杂用水水质标准(GB/T 18920—2002)和景观环境用水水质标准(GB/T 18921—2002)。气水比和回流比对COD的去除影响甚微,但对系统脱氮性能影响较大。在无回流时,随着气水比的增加,氨氮和总氮的去除率增加先快后慢。系统最佳气水比为25∶1,此时出水COD、氨氮、总氮分别为6.91,1.29,26.48 mg/L,对应去除率分别为97.21%,95.68%,31.57%,出水硝氮3.67 mg/L。有回流时(回流比为2),气水比为20∶1,此时出水氨氮质量浓度降低为1.75 mg/L,去除率为93.53%,总氮去除率为46.67%;继续增大气水比,出水氨氮基本为0,总氮的去除率随着气水比的增大先升后降,系统出水硝氮值随着气水比的增加先稍微下降后缓慢升高。采用一体式A/O生物接触氧化工艺,回流并不是必要的。

An intergrated A/O fixed biofilm reactor is used to treat domestic wastewater and the effects of different on the performance of the reactor are studied under conditions： with or without reflux ratio.The results show that the effluent can meet to the standard of reuse（GB/T 18920—2002 and GB/T 18921—2002）,when the influent was 5 L/h,the gas-water ratio was 20∶1,the organic loads of 0.517 kg/（m3·h） and R=3.The R and gas-water ratio had litter impact on the removal of COD,but significantly effect the removal of nitrogen.When without R,the removal of ammonia nitrogen and total nitrogen were increased quickly and then slowly.when the gas-water ratio was 25∶1,the effluent of COD,ammonia nitrogen and total nitrogen were 6.91 mg/L,1.29 mg/L,26.48 mg/L respectively,and the removal rate were 97.21%,95.68% and 31.57% respectively,nitrate was 3.67 mg/L.While reflux ratio was 2,the effluent ammonia nitrogen was decreased to 1.75 mg/L and the removal rate of it and total nitrogen were 93.53% and 46.67% respectively,when the gas-water ratio of the system was 20∶1.The ammonia nitrogen was decreased to 0 if increasing the gas-water ratio again.The removal rate of total nitrogen was firstly increased and then decreased when the gas-water ratio was increased,while the nitrate of the effluent was decreased slowly and then increased slowly.The internal recirculation is not necessary in the intergrated A/O fixed biofilm system.