处理低碳源污水的倒置A^2/O工艺强化脱氮调控

Comprehensive Regulation Technology for Enhancing Nitrogen Removal from Low-carbon Wastewater in Reversed A^2/O Process

重庆市某大型污水处理厂采用倒置A2/O工艺处理低碳源城市污水,针对其在运行中存在的反硝化能力不足、脱氮除磷效果不佳和调控技术的缺陷,进行了强化脱氮综合调控技术的生产性试验研究。在2008年的常温和高温季节,采取投加垃圾渗滤液(投配率为0.1%)、缩短初沉池的HRT为原来的1/3、提高污泥浓度到4 500 mg/L、设置好氧第1段为反硝化过渡段及提高回流比等措施后,增加可利用碳源达15%以上,出水NH3-N为2.5 mg/L,对其去除率为90%;出水TN为17 mg/L,对TN的去除率提高至54%,单位电耗减少了15%(降至0.22 kW.h/m3)。在2008年—2009年的低温季节,采取了提高污泥浓度到约6 000 mg/L、控制好氧区的DO为1.2 mg/L等措施,出水NH3-N为3 mg/L,对NH3-N的去除率为88%;出水TN为15.5 mg/L,对TN的去除率为62%。

Reversed A2/O process was used to treat low-carbon wastewater in a large WWTP in Chongqing, and a full-scale experimental study on comprehensive regulation technology for enhancing ni- trogen removal was conducted to solve poor denitrification capacity, unsatisfactory nitrogen and phosphor- us removal and defect of regulation technology in 2007. When the proposed measures, such as dosing 0.1% landfill leaehate, shortening HRT to 1/3 in the primary sedimentation tank, increasing the sludge concentration to 4 500 mg/L, setting the transition zone in the first aerobic stage and improving the reflux ratio and so on, are applied at normal and high temperature in 2008, over 15% of carbon source can be added. The effluent NH3 - N and TN are 2.5 mg/L and 17 rag/L, and their removal rates are 90% and 54% respectively. The unit electricity consumption is reduced by 15% to 0.22 kW·h/m3. When in- creasing the MLSS to 6 000 mg/L and controlling DO at 1.2 mg/L at low temperature in 2008 to 2009,the effluent NH3 - N and TN are 3 mg/L and 15.5 mg/L, and their removal rates are 88% and 62% respectively.