洱海环湖截污治污工程的治污效果诊断与分析

Performance Diagnosis and Analysis of Sewage Interception and Treatment Project around Erhai Lake

环湖截污治污是控制和治理湖泊富营养化的有效工程手段。洱海环湖截污治污工程运营后,对环洱海的10座污水处理厂2019年的运行效果进行了诊断和分析。结果显示,新建的6座乡镇污水处理厂COD负荷率明显偏低,仅为26.1%~40.7%,但仍取得了较好的COD和氮、磷去除效果;乡镇污水处理厂氮、磷负荷主要与服务片区内的养殖业有关,养殖业发达的上关镇片区氮、磷浓度明显高于中心城区。10座污水处理厂对COD、氨氮和总磷的平均去除率分别为91.7%、97.5%和83.0%,纳入分析的9座污水处理厂对总氮的平均去除率为57.3%。10座污水处理厂出水COD、氨氮和总磷控制指数范围分别为2.00~3.35、6.53~14.20、0.60~10.10,纳入分析的9座污水处理厂出水总氮控制指数范围为1.33~1.99。环湖截污治污工程有效削减了洱海流域的污染负荷,对洱海的水质改善具有重要作用。

Sewage interception and treatment around the lake is an effective engineering method to control lake eutrophication.After the operation of the sewage interception and treatment project around Erhai Lake,the operational performance of 10 sewage treatment plants(STPs)around Erhai Lake in 2019 were diagnosed and analyzed.The COD load rate of the 6 newly-built rural STPs was obviously low,which was only 26.1%-40.7%of the design value.However,good removal performances of COD,nitrogen and phosphorus were still obtained.Nitrogen and phosphorus loads of the rural STPs were mainly related to the aquaculture industry in the service area.The nitrogen and phosphorus concentrations of sewage in Shangguan Town with developed aquaculture industry were significantly higher than those in the central urban area.The average removal efficiencies of COD,ammonia nitrogen and total phosphorus in 10 STPs were 91.7%,97.5%and 83.0%,respectively,and the average removal efficiencies of total nitrogen in 9 STPs included in the analysis were 57.3%.The control indices of COD,ammonia nitrogen and total phosphorus in the effluent from 10 STPs were 2.00-3.35,6.53-14.20 and 0.60-10.10,respectively,and the control index of total nitrogen in the effluent from 9 STPs included in the analysis ranged from 1.33 to 1.99.The sewage interception and treatment project around the lake effectively reduced the pollution load of Erhai Lake Basin and played an important role in improving the water quality of Erhai Lake.