低碳源城市污水的强化脱氮除磷工艺研究

Study on Treatment of Municipal Wastewater with Low Carbon Source by Enhanced Nitrogen and Phosphorus Removal Process

在活性污泥释磷规律研究的基础上进行中试,对常规A2/O工艺进行改进,提出适用于低碳源城市污水的强化脱氮除磷工艺。结果表明:富磷污泥中的NO3--N浓度较高时,在厌氧开始的一段时间内,反硝化吸磷使PO34--P浓度不断降低,当NO3--N由2.75 mg/L降至接近于零时才开始表现出释磷;对于低碳源城市污水,由于大量未被反硝化的NO3--N随回流污泥进入厌氧区,干扰厌氧释磷的正常进行,导致常规A2/O工艺的除磷效果较差,出水TP平均浓度为1.04 mg/L;调整厌氧、缺氧、好氧停留时间比进行强化厌氧后,出水TP平均浓度为0.48 mg/L,达到了GB 18918—2002标准的一级A标准,去除率较常规A2/O工艺提高了21%,同时出水COD、TN、NH3-N也能稳定地达到一级A标准。

Based on the rule of phosphorus release from activated sludge, a pilot research was conducted to improve the conventional A^2/O process. The enhanced nitrogen and phosphorus removal from municipal wastewater with low carbon source was studied. The results demonstrate that at the beginning of phosphorus release from activated sludge with a high concentration of NO3^- - N, the concentration of PO4^3- -P is gradually decreased because of the P-uptake by denitrification. When the concentration of NO3^- - N is decreased from 2. 75 mg/L to near zero, phosphorus release begins. For municipal wastewater with a low carbon source, because a large amount of NO3^- - N which are not denitrified return to the anaerobic tank, the anaerobic phosphorus release is disrupted, which causes the poor phosphorus removal efficiency in the conventional A2/O process. The effluent concentration of TP is 1.04 mg/L. By adjusting the anaerobic, anoxie and aerobic duration ratio and intensifying the anaerobic process, the effluent concentration of TP becomes 0.48 mg/L, which meets the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （ GB 18918 - 2002）. Compared to the conventional A^2/O process, the removal rate of TP is increased by 21%. The concentrations of COD, TN, NH3 -N in the effluent can meet the first level A criteria.