中文摘要：

针对二级城镇污水处理厂提标改造时出水氮、磷指标很难同时达到一级A标准（GB18918-2002）的情况，提出了改良式序批式反应器（MSBR）的强化生物脱氮运行模式，并通过生产性实验研究了MSBR工艺混合液回流比（6单元回流至5单元）对出水COD、TP、NH4＋-N及TN的影响。实验结果表明，MSBR工艺混合液回流比对COD、NH4＋-N去除基本上没有影响，但对TN和TP去除有影响。当回流比从0提高1和1．5时，TP去除效率分别降低了5．85％和4．06％；而TN去除效率分别提高了10．46％和7．87％，同时出水TN可稳定达到一级A标的要求。从控制运行能耗和脱氮效果的角度综合考虑，该污水厂强化生物脱氮的混合液回流比控制在1是比较合适的。

英文摘要：

A full-scale modified sequencing batch reactor（MSBR）process was proposed to enhance total ni- trogen （TN） removal performance from municipal wastewater in order to meet the effluent limit for Grade 1A sew- age treatment plant in China（GB18918-2002）. The full-scale experiment investigated the influence of mixed liq- uor recycle ratio（from 6 cell recycle to 5 cell）on the removal of chemical oxygen demand （COD） , total phos- phorus（TP）, ammonia nitrogen （NH4＋-N） and TN in MSBR process. The experimental results showed that mixed liquor recycle ratio did not affect removal of COD and ammonia, but affected the removal of TN and TP. When the mixed liquor recycle ratio increased from 0 to 1 and 1.5, TP removal efficiency decreased 5.85% and 4.06% , respectively, however, TN removal efficiency increased 10.46% and 7.87% , respectively, and efflu- ent TN can meet the standard requirement. Taking both energy consumption and nitrogen removal efficiency into consideration, the optimized mixed liquor recycle ratio of MSBR process was 1.