以剩余污泥水解酸化液为外加碳源的污水生物脱氮

Biological nitrogen removal of wastewater with hydrolysis-acidification liquor of excess sludge as additional carbon source

为解决低碳氮比污水生物脱氮过程反硝化碳源不足的问题,利用剩余污泥水解酸化液为外加碳源,通过具有曝气段与非曝气段的一体化曝气生物滤池(BAF),研究低碳氮比污水生物脱氮的性能与工艺条件。实验结果表明,预处理后的水解酸化液VFAs为3 134.9～5 251.4 mg/L、ThODVFAs/COD为59.87%～91.85%,适合作为生物脱氮的外加碳源;水解酸化液的投配量、进水TN浓度对系统生物脱氮效果的影响较大,气水比、曝气段与非曝气段比例对系统的硝化和反硝化性能有重要的影响;在温度为25±1℃,水解酸化液COD平均为7 555.1 mg/L,进水TN、NH4+-N和COD分别平均为43.88 mg/L、39.04 mg/L和56.8 mg/L,碳源与污水投配的流量比为1∶75的条件下,当BAF水力停留时间(HRT)为8 h、曝气段与非曝气段比例为3∶3、气水比为10∶1、回流比为2∶1时,NH4+-N和TN的去除率分别超过98%和75%,出水COD平均为28.6 mg/L。研究指出,剩余污泥水解酸化液经过预处理后可用作低碳氮比污水生物脱氮的外加碳源,有效地提高了反硝化效果,并不会造成二次污染,同时又可以实现剩余污泥的减量化和资源化。

In order to solve the problem about the shortage of carbon source for denitrification in the biological nitrogen removal of low C/N ratio wastewater, the integrated biological aerated filter （BAF） with aeration section and non-aeration section was employed to investigate the performances and process conditions for the biological nitrogen removal of low C/N ratio wastewater when the hydrolysis-acidification liquor of excess sludge was used as additional carbon source. The experimental results showed that VFAs and ThODwAJCOD of the hydrolysis-acidification liquor after pretreatment were 3 134.9 -5 251.4 mg/L and 59.87% -91.85% , respectively, which was applicable to the carbon source for biological nitrogen removal. The dosing flow rate of the hydrolysis-acidification liquor and the influent TN concentration had greater impacts on the biological nitrogen removal performances of the system, and the air/water ratio and the ratio of aeration section to non-aeration section played an important role in nitrification and denitrification behaviors of the system. Under the conditions of temperature 25 ± 1℃ , COD average of the hydrolysis-acidification liquor 7 555. 1 mg/L, influent concentrations of TN 43.88 mg/L, NH4^＋-N 39.04 mg/L and COD 56.8 mg/L, the ratio of flow rates of carbon source to influent 1 ： 75, when the hydraulic retention time （HRT） was 8 h, the ratio of aeration section to non-aeration section was 3： 3, the air/water ratio was 10： 1, and the recirculation ratio was 2： 1, the removal efficiencies of NH4^＋ -N and TN were above 98% and 75% , respectively, and the effluent COD average was 28.6 mg/L. This research indicated that the hydrolysis-acidification liquor of excess sludge could be utilized as carbon source for biological nitrogen removal of low C/N ratio wastewater, the denitrification performances could be effectively improved and the second pollution would not be caused. Meanwhile the minimization and resources reuse of excess sludge could be realized as well.