Abstract: A long-term continuous experiment of simulated wastewater was carried out using A²/O process and effect of influent loading and reflux ratio on the removal efficiency of nitrification was investigated at low MLSS of （1500±200） mg/L. The results show that the influent loading increases gradually from 5.03 gCOD/（gMLSS·d）to 10.05 gCOD/（gMLSS·d）and removal efficiency of COD is higher than 95% when influent loading is changed by adjusting influent flow rate. Removal efficiency of NH₄⁺-N increases from 69.59% to 95% and removal efficiency of TN increases from 53.53% to 80%，respectively. Furthermore，when influent loading is enhanced to 20.31 gCOD/(gMLSS·d)，removal efficiencies of NH₄⁺-N and TN decrease to 50% and 40%，respectively. The influent loading increases from 10.05 gCOD/(gMLSS·d) to 124.11 gCOD/(gMLSS·d) when influent loading is changed by adjusting influent COD. Removal efficiencies of COD and NH₄⁺-N are all higher than 90% and removal efficiency of TN increases gradually from 70% to 80%，respectively. When the reflux ratio of mixture is 300%，200% and 100%，respectively，removal efficiencies of COD and NH₄⁺-N are less affected by reflux ratio. Removal efficiencies of COD and NH₄⁺-N are higher than 90% and 95%，respectively. And meantime，removal efficiency of TN drops with the increasing reflux ratio，which is greatly influenced by reflux ratio. When the internal reflux ratio is 100%，removal efficiency of TN reaches the highest and it is higher than 80%.

Key words: A²/O, sludge concentration, influent loading, reflux ratio of mixture

摘要： 采用连续流A²/O工艺对模拟生活废水进行了长期连续实验，考察了低污泥浓度[MLSS=(1500±200) mg/L]下进水负荷与回流比对脱氮效率的影响。结果表明，通过调节进水流量改变进水负荷，当进水负荷从5.03 gCOD/(gMLSS·d)逐渐提高至10.05 gCOD/(gMLSS·d)时，COD去除率≥95%，氨氮去除率由69.59%升高为95%，总氮去除率由53.53%升高到80%；当进水负荷由10.05 gCOD/(gMLSS·d) 提高至20.31 gCOD/(gMLSS·d)时，氨氮去除率下降为50%，总氮去除率下降为40%。通过调节进水COD改变进水负荷，当进水负荷从10.05 gCOD/(gMLSS·d) 逐渐提高到124.11 gCOD/(gMLSS·d) 时，COD和氨氮的去除率均>90%，总氮去除率从70%逐渐增加到85%。在混合液回流比分别为300%、200%和100%的条件下，回流比对COD和氨氮去除效果影响较小，COD去除率≥90%，氨氮去除率≥95%；回流比对总氮去除效果影响较大，随回流比的增大总氮去除率减小。当内回流比为100%时，总氮去除率最高，达到79.76%。

关键词: A²/O, 污泥浓度, 进水负荷, 混合液回流比