DO浓度对MBR运行效果的影响研究

Study on influence of DO concentration on running effect of MBR

为了研究DO浓度对MBR运行效果的影响,选取DO的质量浓度分别为(1.0±0.2)、(3.5±0.2)、(6.0±0.2)mg/L进行纵向对比试验,以CODCr、NH3-N浓度和脱氢酶活性(DHA)为考察指标,分析DO浓度对MBR运行效果的影响规律。试验结果表明,当DO的质量浓度为3.5 mg/L时,MBR的CODCr生物去除率、NH3-N生物去除率及NH3-N系统去除率较DO的质量浓度为1.0、6.0 mg/L时的大,各DO浓度条件下的CODCr系统去除率无明显差别;各DO浓度条件下,膜对CODCr补偿作用明显,对NH3-N补偿作用不明显;当DO的质量浓度为3.5 mg/L时,MBR混合液的DHA较DO的质量浓度为6.0、1.0 mg/L的要大,其值为15.77 mg[TF]/(h·L)。DO浓度对MBR运行效果的影响表现为:DO浓度适宜,可促进MBR中CODCr、NH3-N的生物去除,提高MBR的微生物活性。膜对CODCr补偿作用明显,对NH3-N补偿作用不明显。

In order to study the influence of DO concentration on running effect of MBR, a comparative ex- periment on MBR with DO mass concentrations of （1.0± 0.2）, （3.5 ± 0.2） and （6.0 ± 0.2） mg/L respectively was carried out. Taking CODcr concentration, NH3-N concentration and dehydrogenase activity （DHA） as the research indicators, the influence of DO concentration on running effect of MBR were analyzed. The results of the experiment showed that, when the mass concentration of DO was 3.5 mg/L, the biological removal rates of CODcr NH3-N and the systematic removal rate of NH3-N were all higher than those of the MBR with DO mass concentrations of 1.0 and 6.0 mg/L. There was no significant difference among the systematic removal rates of CODcr under different DO concentration conditions; the compensation action of the membrane for CODcr was more obvious than for NH3-N. When the mass concentration of DO was 3.5 mg/L, the DHA of the mixed liquid in MBR was 15.77 mg[TF]/（L·h） which was higher than that with DO mass concentrations of 6.0 and 1.0 mg/L. The study clearly indicated that a proper concentration of DO was helpful to the biological removal of CODcr and NH3-N, as well as the improvement of biological activity of MBR.