A2O工艺处理生活污水反硝化除磷研究
Study on Denitrifying Phosphorus Removal From Domestic Wastewater in A2O Process
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摘要: 采用A2O工艺处理低ρ(C)/ρ(N)实际生活污水,研究其脱氮除磷性能和反硝化除磷特性.试验结果表明:处理低ρ(C)/ρ(N)实际生活污水时,在不设置预缺氧区、无外加碳源的情况下,A2O工艺的脱氮除磷能力受到严重影响,出水ρ(NO3--N)高达35 mg/L,TN平均去除率仅为47.1%;此时A2O工艺除磷能力较差,缺氧段有释磷现象的发生.当设置预缺氧区后,A2O工艺的脱氮除磷能力明显提高,TN平均去除率可达60.7%,PO43--P平均去除率为55.9%;此时系统存在反硝化除磷现象,缺氧段除磷率为31.4%~46.9%.在设置预缺氧区的基础上,通过外加碳源,提高进水ρ(C)/ρ(N),可进一步提高系统的脱氮除磷能力,TN平均去除率可达74.4%,出水ρ(PO43--P)小于0.5 mg/L,缺氧段除磷率高达66.2%~90.9%.同时研究了外加碳源情况下污泥内PHA成分、含量及糖原含量在A2O系统内的沿程变化趋势.经过驯化、富集,反硝化聚磷菌相对于全部聚磷菌的代谢活性从31.1%提高到74.7%.A2O工艺反硝化除磷能力的增强,提高了碳源的利用效率.Abstract: A lab-scale A2O process was operated to investigate the performance of biological nutrients removal and denitrifying phosphorus removal from low ρ(C)/ρ(N) ratio domestic wastewater.The results showed that only about 47.1% of TN could be removed with effluent ρ(NO3--N) above 35mg/L when the A2O process was operated without the pre-anoxic zone and additional carbon source.Under this condition,both conventional and denitrifying phosphate removal was not observed in the anoxic zone.When the A2O process was operated with the pre-anoxic zone,about 60.7% of TN and 55.9% of PO43--P could be removed.Moreover,denitrifying phosphate removal occurred with a removal efficiency of 31.4%-46.9% in the anoxic zone.After the ρ(C)/ρ(N) ratios were increased by adding the carbon sources,biological nutrients removal was enhanced with the TN removal of 74.4% and the ρ(PO43--P) in the effluent below 0.5mg/L,and the denitrifying phosphate removal efficiency was up to 66.2%-90.9%.Furthermore,the variations of PHA and glycogen were investigated.The relative metabolic activity of the DNPAO(denitrifying phosphate accumulating organism) increased from 31.1% in the seed sludge to 74.7% in the acclimated sludge.The carbon sources utilization efficiency is upgraded with the achievement in denitrifying phosphate removal in the A2O process.
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