Treatment Of Cesium And Strontium Loaded Wastewater And Micro-polluted Source Water By Microfiltration Combined Process

As membrane technology becomes more mature, microfiltration combined process in water treatment field has been developed rapidly. The advantages of this process involve high degree of automation, small floor area, efficient treatment effect, well and stable quality of produced water, etc. This paper mainly studied treatment effeciency of cesium and strontium loaded wastewater and micro-polluted source water by microfiltration combined process.The coagulation co-precipitation followed by microfiltration process was applied to treatment of non-radioactive wastewater containing cesium and strontium. The system of the process was continuously operated, and treated water from precipitation reactor after coagulation and precipitation was separated by microfiltration membrane. Average removal efficiencies of cesium and strontium were 9.4% and 82.7%, respectively. Concentration factor was 919. The average turbidity of produced water from membrane was 0.06 NTU. Specific flux of the membrane declined slowly with the increasing of treated water, and after physical cleaning, it could recover to 92.6% compared with that of the new membrane.Cupric ferrocyanide was selected as adsorbent used in adsorption-microfiltration process to treat non-radioactive wastewater containing cesium and prepared by the method of chemical precipitation-cleansing. The results of spectral analysis on the adsorbent proved that the preparation method was valid and reproducible. Sequencing batch system of the process was used to treat raw water with 100μg/L cesium, dosing 40 mg/L cupric ferrocyanide. Cesium removal efficiency was higher than 99.7% with average decontamination factor of 461 and concentration factor of 957. The turbidity of produced water from membrane stabilized at 0.06 NTU. Decrease rate of specific flux became slower gradually, and after physical cleaning, specific flux could recover to 94.3% compared with that of the new membrane.Integrated water purified equipment of microfiltration membrane was used to treat micro-polluted source water, and the device integrates coagulation-sedimentation and microfiltration process. When dosing 20 mg/L ferric chloride as flocculant, for the raw water with high turbidity and high algae (turbidity more than 40 NTU), average turbidity removal efficiency was about 99.3%, and COD_Mn of produced water fluctuated between 2.84³.24 mg/L, meeting the requirement of Standards for Drinking Water Quality. When the total production reached 87.5 cubic meters, membrane was cleaned with physical and chemical method by 0.1% sodium hypochlorite. Specific flux could recover to 40.2% and 78.4%, respectively, so organic matter and algae were the main causes of membrane fouling problem. After cost estimation, water production cost was about 0.792 yuan per cubic meter.