COD对2种绿藻共培养处理农村生活污水的影响

Effects of COD on treatment efficiency of co-culture of two green algae in rural domestic sewage

目的:探究不同化学需氧量(Chemical Oxygen Demand,COD)对藻类生长及污水中氮磷去除的影响。方法:以蛋白核小球藻和四尾栅藻(2∶1混合)为研究对象,处理不同COD的模拟农村生活污水。结果:在2~6 d,叶绿素A含量增长率随COD初始值增加而降低,COD_(400)、COD_(500)处理组的pH显著低于COD_(250)、COD_(300)处理;第2天COD_(300)、COD_(400)和COD_(500)处理组的溶解氧(DO)趋于0,且在2~4 d,DO上升幅度随COD初始浓度的增加而递减。COD_(300)对水体铵态氮的去除效果最好,最终去除率达63.3%,并显著高于COD_(500);各处理组的总磷去除率随COD初始值的增加而显著上升,其中COD_(500)处理对总磷的最终去除率达94.2%。结论:随COD升高,延缓了叶绿素A的增加以及pH和DO升高,而高浓度COD促进了总磷的去除,降低了铵态氮的去除。

Objective:The aim of the study was to explore the effects of different chemical oxygen demand(COD)on algae growth and removal of N and P in sewage.Methods:In this study,Chlorella pyrenoidosa and Scenedesmus quadricauda taking 2∶1 mixed algae species were used to treat simulated rural domestic sewage with different COD.Results:After 2—6 days,the growth rate of chlorophyll A content decreased with the increase of COD initial concentration,and the pH of COD_(400)and COD_(500)was significantly lower than that of COD_(250)and COD_(300).On the second day,the DO tended to zero for the treatment groups of COD_(300),COD_(400)and COD_(500).After 2—4 days,the rising range of DO decreased with the increase of COD initial concentration.COD_(300)had the best removal effect on NH_(4)^(+)-N in water,and the final removal rate was 63.3%,which was significantly higher than that of COD_(500).The removal rate of total phosphorus increased significantly with the increase of COD initial value,and the final removal rate of total phosphorus in COD_(500)reached 94.2%.Conclusion:As the concentration of COD increased,the growth of chlorophyll A and increases of pH and DO were delayed,and higher concentration of COD promoted the removal of total phosphorus and reduced the removal of NH_(4)^(+)-N.