氧化沟低溶解氧运行模式下的脱氮除磷效果分析

目的]研究低溶解氧条件对氧化沟的脱氮除磷效果。方法]通过在2.0、1.0和0.5 mg/L溶解氧浓度下对氧化沟脱氮除磷效果进行的分析比较,选择溶解氧浓度范围为0.5～1.0mg/L,进行连续低氧运行与间歇低氧运行2种运行方式的中试试验。间歇运行根据曝气/停止曝气时间分为工况1(60 min/20min),以及工况2(70 min/20 min)进行试验。结果]连续低氧运行时,氨氮与COD处理效果较好,平均去除率为84%和91%,TN和TP平均去除率为46%和70.1%;间歇运行时,工况1中,COD和氨氮的去除率仍然较好,同时反硝化程度提高,出水TN平均去除率为61%,TP平均去除率仅能达到55%;工况2中,COD和氨氮的去除率与工况一相似,TN平均去除率增至63%,出水TP平均去除率可达72%。结论]间歇工况2是3种运行模式中较好的一种。

Analysis on Effect of Nitrogen and Phosphorus Removal in Oxidation Ditch under Modes of Low Dissolved Oxygen

Objective] The study aimed to research the effect of the nitrogen and phosphorus removal in the oxidation ditch under the condition of low dissolved oxygen(DO).Method] The pilot test was conducted on the 2 operation modes of the continuous hypoxia and intermittent hypoxia under the DO concn.range from 0.5 mg/L to 1.0mg/L selected through the analysis and comparison on the effect of the nitrogen and phosphorus removal in the oxidation ditch under the DO concn.of 2.0,1.0 and 0.5 mg/L.The intermittent hypoxia operation was divided into the condition 1 of 60 min/20 min and condition 2 of 70 min/20 min according to the different aeration/stop time.Result] In the continuous hypoxia mode,the removal of ammonia nitrogen and COD was very good,with the average removal ratio of 84% and 91% resp.;the average TN and TP?removal ratio could reach 46% and 70.1%,resp.During the intermittent hypoxia operation,in the condition 1,the removal ratios of COD and ammonia nitrogen were still good,at the same time,the higher level of denitrification was achieved,so that the average removal ratio of the filtered effluent TN could attain 61%,but TP removal ratio could only reach 55%;in the condition 2,the removal ratios of COD and ammonia nitrogen were similar to the condition 1,the average removal ratio of the TN was increased to 63% and the average removal ratio of the filtered effluent TP was rose to 72%.Conclusion] The intermittent condition 2 was the best among the three operation modes.