Application Of Microfiltration-reverse Osmosis On Treatment Of Circulating Cooling Water With High Chloride

The high concentration of chloride ion in the circulating cooling water can cause serious corrosion to the system,and a large number of organic matter in the water is easy to cause the system to breed microorganisms,which is not conducive to the environmental safety of the food processing industry.In this paper,the reverse osmosis method was used to treat the pollutants such as chloride and COD_Cr in the simulated wastewater.The removal efficiency of the system was analyzed and the optimal operating conditions were investigated.The stability of the whole reverse osmosis system was investigated by dynamic experiment,and the optimization scheme was put forward.This study adopted"activated carbon filtration,PP cotton filter and microfiltration"three level combination technology as the pretreatment of reverse osmosis membrane,and the SDI value of effluent was between 2.1 and 3.0.The factors that affect the efficiency of reverse osmosis were selected,and mainly included:operating pressure,feed concentration,operating temperature and pH.Through single factor experiment and orthogonal experiment,the effects of various factors on the rate of desalination,membrane flux and water yield were studied,and the experimental results showed that the operating pressure,feed concentration and operating temperature were significant factors.The order of the effect of the desalination rate was the operating pressure,feed concentration and operating temperature,while the order of the effect of the membrane flux was the operating pressure,operating temperature and feed concentration.pH had little effect on the performance of reverse osmosis membrane.The optimal operating conditions was operating pressure 1.6MPa,operating temperature 25degrees Celsius.Under the optimal conditions of this operation in the continuous microfiltration-reverse osmosis system,analysed the long-term operation of the treatment effect of sewage treatment and the stability of the method.The experimental results showed that the average removal rate of chloride ion,COD_Cr and turbidity were 30%,64%and 79%respectively,and the SDI value of effluent was between 2 and 3.After pretreatment of the effluent meet the test using reverse osmosis membrane water requirements.The average removal rates of chloride ion,COD_Cr,turbidity and calcium hardness were 98%,96%,100%and 97%respectively.The chloride ion,COD_Cr,calcium concentration and turbidity of the whole system were reduced to 120mg/L,5mg/L,4mg/L and 0NTU,at the same time,membrane flux was monitored.Through the study on the design of the microfiltration-reverse osmosis system,the main pollutants in raw water was removed,reducing the degree of harm of the corrosion,scaling and microbe to the equipment used for circulating cooling water,prolongation the duration of cooling water,and exploring the pollution and the cleaning of reverse osmosis membrane.The research results could provide technical reference for the design of water treatment device,and had strong engineering significance.