化学除磷比值对低碳源污水脱氮除磷的影响

为解决低碳源城市污水高效脱氮除磷及磷回收问题,开发了侧流A2O工艺,通过抽取不同量的厌氧池末端富磷上清液至化学除磷池,来研究系统的脱氮除磷效果及磷回收情况。结果表明,在无需增加额外碳源,进水COD为136～168 mg/L、NH3-N为32～40 mg/L、TN为36～45mg/L、TP为6～8 mg/L的条件下,当化学除磷比(富磷上清液抽取量与进水量之比)为10%～20%时,对TN和TP的平均去除率分别可达到95.7%、84%,其中,当化学除磷比为15%时,出水TP浓度可降至0.5 mg/L以下,出水水质达到《城镇污水处理厂污染物排放标准(》GB 18918—2002)的一级A标准;同时,回收磷量可达进水磷量的23%～29%,既实现了磷的可持续发展,又增加了污水厂的经济效益。

Effect of Chemical Phosphorus Removal Ratio on Nitrogen and Phosphorus Removal from Low Carbon Municipal Wastewater

Side-stream A2O process was developed to improve the ability of nitrogen and phosphorus removal from low carbon municipal wastewater and the phosphorus recovery.The nitrogen and phosphorus removal and phosphorus recovery were studied by pumping different amounts of phosphorus-rich supernatant in the end of anaerobic tank into chemical phosphorus removal tank.Under the conditions of the influent COD of 136 to 168 mg/L,NH3-N of 32 to 40 mg/L,TN of 36 to 45 mg/L,TP of 6 to 8 mg/L and no additional carbon source,the removal rates of TN and TP were 95.7% and 84% when the chemical phosphorus removal ratio(ratio of phosphorus-rich supernatant amount to influent amount) was 10% to 20%.The effluent TP concentration was lower than 0.5 mg/L at the chemical phosphorus removal ratio of 15%.The effluent quality could reach the first criteria class A specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918-2002).In addition,the amount of phosphorus recovery was 23% to 29% of the influent phosphorus,thus achieving phosphorus sustainable development and increasing the economic benefit of WWTP.