Study On The Application Of Double Membrane Method In Zero Discharge Process Of Copper-containing Wastewater

Combined with the hazard of copper-containing wastewater and the national requirements for clean production reform of heavy metal wastewater related industries,this paper analyzes and studies the copper-containing wastewater treatment process and finds that the traditional copper-containing wastewater treatment process has reached the requirement of the Integrated Wastewater Discharge Standard（GB8978-1996）for total copper emission limit of 0.5 mg/L in the first-class standard,but failed to meet the“zero discharge”requirement of national water pollution control for heavy metal wastewater,and the advanced treatment of copper-containing wastewater needs to be solved urgently.The advanced treatment technology of copper-containing wastewater needs to have the characteristics of no secondary pollution and heavy metal recovery.The membrane separation method stands out because of its low energy consumption,high efficiency,wide application range,simple process,low investment,light pollution and easy automation.In this experiment,the ultrafiltration-reverse osmosis double membrane method was used to study the advanced treatment of copper-containing wastewater.The specific research contents are as follows:（1）The effects of operating pressure,membrane flux and filter cycle on ultrafiltration effluent quality,water production recovery and membrane fouling were studied by changing the operating conditions of ultrafiltration.（2）By changing the reverse osmosis operating conditions,the effects of operating pressure and concentrated water return flow on water quality,water production,recovery rate and system salt rejection were studied.（3）Combined operation of ultrafiltration-reverse osmosis double membrane process for the treatment of copper-containing wastewater,study the operation stability of the double membrane process,and analyze the membrane fouling,the quality of the inlet and outlet water and the treatment cost.The conclusions of this test are as follows:（1）Ultrafiltration production water recovery rate and membrane fouling are related to ultrafiltration operation pressure,membrane flux and filter cycle.Increases in operating pressure,membrane flux,and filter cycle will increase water recovery,but will also increase membrane fouling.In addition,both the operating pressure and the membrane flux have little effect on the quality of the superfluid effluent,and the increase in the filter cycle has a small effect on the ultrafiltration effluent SDI and turbidity.Under the conditions of this test,the conditions for selecting the copper-containing wastewater by ultrafiltration are:operating pressure 0.1 MPa,membrane flux 80L/（m²·h）,and filter cycle 45 min.（2）Reverse osmosis water production,recovery rate,and salt rejection rate are all related to operating pressure and concentrated water return flow.The operating pressure increases,the reverse osmosis water yield increases,the recovery rate increases,the system desalination rate becomes larger;the concentrated water return flow increases,the reverse osmosis water production decreases,the system recovery rate increases,and the system desalination rate decreases.In addition,both the operating pressure and the concentrated water return flow have little effect on the quality of the reverse osmosis water.Under the test conditions,the operating pressure of the reverse osmosis system is selected to be 5.5 MPa,and the concentrated water return flow rate is preferably 50%of total water supply.（3）During the 30-day test run of the double membrane method,the working condition is stable and the treatment effect is good.The ultrafiltration transmembrane pressure difference fluctuates between 56⁷6 KPa,and the effluent turbidity and SDI are both stable at a low level,which meets the requirements of reverse osmosis membrane water inlet;the reverse osmosis unit works well,the water production floats up and down at 60 L/h,desalting The rate is more stable than 99.4%,the difference between the two is small,and the reverse osmosis membrane is slightly polluted.Ultrafiltration-reverse osmosis double membrane method has good removal effect on Cu²⁺,COD,SS,NH₃-N,conductivity and turbidity in copper-containing wastewater.At the same time,according to the above test results,the double membrane process was applied to the copper-containing wastewater advanced treatment project of a technology company in Hunan.After treatment,the produced water was directly used in the enterprise production line.The total reuse rate of the water was 82.5%,and The treatment cost per ton of water is 2.82 yuan.The project has good economic and environmental benefits and can be used as a reference for similar upgrade projects.