DAT-IAT改进工艺对生活污水中氨氮的去除

以需氧池-间歇曝气池（DAT-IAT）工艺为基础，在其后设置一生物接触氧化反应器，考察了该组合工艺对生活污水中氨氮的去除效果。结果表明，在IAT池以曝气2h、沉淀1h、出水1h的工况运行及生物接触氧化反应器的HRT为3h的条件下，系统对氨氮的平均去除率为81．1％，出水氨氮平均浓度为7．0mg／L，满足《城市污水再生利用城市杂用水水质》（GB／T 18920-2002）的要求。系统对氨氮的去除率随着进水COD浓度的提高而下降，当进水COD为815．3mg／L时，出水氨氮浓度仍可满足GB／T 18920-2002的要求；随着进水氨氮浓度的提高，系统对氨氮的去除率先略有上升后明显下降，为保证出水氨氮浓度达到回用标准，应将进水氨氮浓度控制在50mg／L以下；系统适宜的pH值范围为7～8，pH值过高或过低都会造成系统对氨氮去除率的显著下降。

Modified DAT/IAT Process for Removal of Ammonia Nitrogen from Domestic Sewage

A biological contact oxidation reactor was set up behind demand aeration tank/intermittent aeration tank(DAT/IAT).The removal effect of ammonia nitrogen from domestic sewage in the combined process was investigated.The results show that when the operating periods of IAT are set at two hours for aeration,one hour for sedimentation,one hour for drainage,and HRT of the biological contact oxidation reactor is three hours,the combined system is able to remove an average of 81.1% for ammonia nitrogen,and the average ammonia nitrogen concentration in the effluent is 7.0 mg/L.The effluent quality meets the requirements of the Reuse of Urban Recycling Water-Water Quality Standard for Urban Miscellaneous Water Consumption(GB/T 18920-2002).The removal efficiency of ammonia nitrogen declines along with the increase of influent COD concentration.When the influent COD is 815.3 mg/L,the effluent ammonia nitrogen concentration still meets the requirements of GB/T 18920-2002.However,as the influent ammonia nitrogen concentration gradually increases,the removal efficiency of ammonia nitrogen slightly increases at first and then obviously decreases.The influent ammonia nitrogen concentration should be controlled at below 50 mg/L to ensure the effluent ammonia nitrogen concentration reach the reuse standard.The appropriate pH range is 7 to 8,and the values outside this range may cause the decrease in the removal efficiency of ammonia nitrogen.