Engineering Design And Operation Effect Study Of Sewage Treatment Plant Of A PCB Industrial Park In L County

With the improvement of people’s environmental awareness and the strengthening of industry wastewater discharge supervision,the effective treatment and reuse of PCB wastewater has become an urgent and important issue to be solved.Based on the production process of a PCB park enterprise in L County,this study predicts the amount and quality of wastewater in the park,demonstrates and determines the treatment plan and reuse process plan for comprehensive wastewater,organic wastewater,complexed wastewater,RO concentrated water,and engineering design for various types of wastewater treatment and reuse water treatment;After the construction and operation of the sewage treatment plant,the effluent quality will be monitored and the operational effectiveness of the designed sewage treatment system will be analyzed.The main conclusions are as follows:The design scale of the PCB industrial park sewage treatment plant is 8000m~3/d.By comparing and demonstrating sewage treatment process plans,various wastewater treatment processes have been determined.The comprehensive wastewater treatment process flow is:comprehensive wastewater-regulating tank-pH regulating tank(I,II)-coagulation tank&flocculation tank-sedimentation tank-intermediate water tank(comprehensive)-reuse system.The process flow of complex wastewater treatment is as follows:complex wastewater-regulating tank-pH regulating tank I-breaking reaction tank-pH regulating tank II-coagulation tank&flocculation tank-sedimentation tank-intermediate water tank(complex)-A~3/O-MBR system-production water tank(complex)-reuse system.The process flow of organic wastewater treatment is as follows:organic wastewater-regulating tank-pH regulating tank I-breaking reaction tank-pH regulating tank II-coagulation tank&flocculation tank-sedimentation tank-intermediate water tank(network)-A~3/O-MBR system-production water tank(network)-reuse system.The process flow of RO concentrated water treatment is as follows:RO concentrated water-membrane concentrated water regulation tank-pH regulation tank I-reaction tank-pH regulation tank II-coagulation tank&flocculation tank-sedimentation tank-intermediate water tank(RO)-A~3/O-MBR biochemical system-production tank-clean water discharge tank.The process flow of the comprehensive reuse system is as follows:treated comprehensive wastewater-intermediate water tank(comprehensive)-multi medium filter-self-cleaning filter-plate and frame heat exchanger-UF system-ultrafiltration tank-primary NF system-secondary RO system-reuse water tank(membrane concentrated water regulating tank).The process flow of the complexation reuse system is as follows:treated complexation wastewater,organic wastewater-production water tank(complex)-multi medium filter-security filtration-primary reverse osmosis-secondary reverse osmosis-reuse water tank(membrane concentrated water regulating tank).Based on the above treatment process flow,various main structures have been designed.After the construction and stable operation of the sewage treatment plant,the average removal rate of COD in the comprehensive wastewater pretreatment system is 52.7%,the average removal rate of ammonia nitrogen in the comprehensive wastewater is 63.1%,and the average removal rate of total copper in the comprehensive wastewater is 98.2%.The average removal rate of COD in organic wastewater and complex wastewater treatment system is 93.3%,while the average removal rate of COD in complex wastewater is 88.9%;The average removal rate of ammonia nitrogen in organic wastewater is 80.0%,and the average removal rate of ammonia nitrogen in complex wastewater is 85.6%;The average removal rate of total copper in organic wastewater is 98.1%,and the average removal rate of total copper in complex wastewater is 99.9%.The RO concentrated water treatment system has an average removal rate of 88.1%for COD in wastewater,95.0%for ammonia nitrogen in wastewater,and 95.1%for total copper in wastewater.The removal effect is good.The analysis results of the effluent quality of the sewage treatment plant show that the COD of the effluent is 19.8-36.7mg/L,the SS concentration of the effluent is 14.3-25.6mg/L,the ammonia nitrogen concentration of the effluent is 0.6-1.7mg/L,and the total phosphorus and total copper concentrations of the effluent are maintained below 0.15mg/L,which can meet the requirements of Table 3 of the"Electroplating Pollutant Discharge Standard"(GB21900-2008).The research provides a good guarantee for the sewage treatment of the PCB park in L County,and also provides reference for the construction and operation of sewage treatment plants in the PCB industry.The implementation of the project has improved the local water environment quality and promoted sustainable economic development.