夏冬两季AAO工艺微孔曝气系统性能测定与评价

Determination Measurement and Evaluation of Aeration Performance of Fine-Pore Aeration System for AAO Process in Summer and Winter

以上海某城镇污水处理厂为研究对象,在夏冬两季通过好氧池沿程实地测试,对污染物去除效果和曝气系统性能进行系统测定与评价。结果表明,冬季水量负荷较夏季低,好氧池反应时间延长且充分曝气,抵消了低温对硝化的负面影响,因此,夏冬两季出水水质均达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A排放标准。与夏季相比,冬季生物处理工艺的需氧量更高,微孔曝气系统的氧传质效率更低,导致所需供气量更高,曝气效率更低。夏季和冬季供氧量比需氧量分别高38.99%和7.07%,夏季节能潜力较大。好氧池污染物浓度沿程下降,末端污染物浓度几乎不变,而末端溶解氧浓度远高于前端,说明末端的供氧并未用于COD_(Cr)氧化和氨氧化作用,存在过度曝气现象,因此,可适当降低好氧池末端供气量。

A municipal wastewater treatment plant(WWTP)in Shanghai was taken as the research object.The pollutant removal effect and aeration system performance were systematically measured and evaluated through field tests along the aerobic tank in summer and winter.Results showed that the effluent quality in both summer and winter met the first class A discharge standard of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918—2002),because the hydraulic load was less in winter than in summer and the aerobic tank had longer hydraulic residence time and adequate aeration,which offset the negative effect of low temperature on nitrification.Compared with those in summer,the total oxygen demand of the biological treatment process in winter was higher and the oxygen transfer efficiency of the fine-pore aeration system was lower,resulting in a higher required air supply and lower aeration efficiency.The oxygen supply was 38.99%and 7.07%higher than the oxygen demand in summer and winter,respectively,with a higher energy saving potential in summer.The pollutant concentration of aerobic tank gradually decreases along the tank,and the pollutant concentration at the end remains almost the same,while the dissolved oxygen concentration at the end was much higher than the front end,which meant that the oxygen supply at the end was not used for COD_(Cr) oxidation and ammonia oxidation,therefore over-aeration occurs,so the air supply at the end of aerobic tank can be reduced.