混合液回流比对改良型氧化沟工艺反硝化除磷的影响

以生活污水培养驯化污泥的小试规模氧化沟工艺为研究对象,进行了混合液回流比为100%、200%和300%时对反硝化除磷的影响研究。结果表明:在试验条件下,混合液回流比对TP去除效果影响不大,但去除途径不同,当混合液回流比为200%和300%时,TP主要是在缺氧区通过反硝化除磷去除的,而混合液回流比为100%时,TP主要是在好氧区去除的;随着混合液回流比增加,NH+4-N和TN去除率也有所增加。在混合液回流比为200%时,系统脱氮除磷效果最好,出水TP和TN去除率分别达到93.9%和82.6%,且NO-3-N可以在缺氧区作为电子受体提供给反硝化除磷。从控制运行能耗和反硝化除磷的角度综合考虑,混合液回流比控制在200%是较适宜的。

INFLUENCE OF MIXED LIQUOR RETURN RATIO ON DENITRIFYING PHOSPHORUS REMOVAL IN MODIFIED OXIDATION DITCH

Based on a laboratory scale oxidation ditch process acclimated with domestic wastewater as carbon source，the effect of mixed liquor reflux ratio on denitrifying phosphorus removal in the system was investigated at the mixed liquor reflux ratio of 100%，200% and 300%，respectively． The results showed that mixed liquor reflux ratio did not affect removal effect of TP， but affected the removal mode of TP under the experimental conditions． When the mixed liquid return ratio was 200% and 300%，most of the TP was removed in anoxic zone through the denitrifying phosphorus removal mode，and the mixed liquid return ratio was 100%，most of the TP was removed in aerobic zone． In general，with mixed liquid return ratio increasing，the removal rate of NH + 4 －N and TN were also increased． While the mixed liquid return ratio was 200%，the system obtained the highest nutrient removal efficiency with the removal rate of TP and TN reaching to 93. 9% and 82. 6% respectively，and NO－ 3 －N was sufficient in the anoxic zone as electron acceptor for denitrifying phosphorus removal． Taking both energy consumption and denitrifying phosphorus removal into consideration，the optimized mixed liquor return ratio of the process was 200%．