A pilot-scale study of the integrated ultrafiltration process with floc adsorption
LIU Yansong1,2,, KANG Yongfeng3, WU Siqi2, MA Baiwen2,, 1.School of Environment, Northeast Normal University, Changchun 130024, China 2.Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 3.BCED Environmental Development Co. Ltd., Beijing 100192, China
Abstract:The integrated adsorption-based ultrafiltration (UF) process has attracted much attention due to its small land-occupation. However, granular adsorbents, such as activated carbon, nanoscale-iron, even sand, which were always investigated in previous studies, not only caused the membrane surface damage during filtration, but also lacked the related practical operation parameters. It’s well known that the hydrolyzed flocs are loose and their adsorption ability is strong. Therefore, the pilot-scale performance of the integrated floc-UF process was investigated with the raw water obtained from a river in Changzhou, Jiangsu. The results showed that cake layer was the main fouling mechanism of UF. In comparison with the powder activated carbon (PAC) and iron-based flocs, the aluminum-based floc-UF process performed worse. Owing to the more looseness of flocs compared with powder activated carbon, lower fouling degree occurred with iron-based UF process because of the thinner cake layer and thus lower pollutant load induced on membrane surface. In addition, compared with the UF membrane alone, the operation time increased by 71.4% and 100% after the addition of optimum dosage of powder activated carbon or iron salts. Moreover, although the microorganisms in the membrane tank were inactivated by chlorination pretreatment, the membrane fouling was alleviated to a certain extent. For the effluent quality, the average effluent turbidity of the integrated iron-based-floc-UF process was lower than 0.1 NTU, and the iron concentration was lower than the national standard (GB5749-2006). The removal rates of total organic carbon, total phosphorus and ammonia nitrogen also increased to some extent. Key words:ultrafiltration/ flocs/ PAC/ integrated process/ pilot-scale/ membrane fouling.
图1实验装置示意图 Figure1.Schematic diagram of the pilot-plant
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1.School of Environment, Northeast Normal University, Changchun 130024, China 2.Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 3.BCED Environmental Development Co. Ltd., Beijing 100192, China Received Date: 2021-01-24 Accepted Date: 2021-04-01 Available Online: 2021-06-25 Keywords:ultrafiltration/ flocs/ PAC/ integrated process/ pilot-scale/ membrane fouling Abstract:The integrated adsorption-based ultrafiltration (UF) process has attracted much attention due to its small land-occupation. However, granular adsorbents, such as activated carbon, nanoscale-iron, even sand, which were always investigated in previous studies, not only caused the membrane surface damage during filtration, but also lacked the related practical operation parameters. It’s well known that the hydrolyzed flocs are loose and their adsorption ability is strong. Therefore, the pilot-scale performance of the integrated floc-UF process was investigated with the raw water obtained from a river in Changzhou, Jiangsu. The results showed that cake layer was the main fouling mechanism of UF. In comparison with the powder activated carbon (PAC) and iron-based flocs, the aluminum-based floc-UF process performed worse. Owing to the more looseness of flocs compared with powder activated carbon, lower fouling degree occurred with iron-based UF process because of the thinner cake layer and thus lower pollutant load induced on membrane surface. In addition, compared with the UF membrane alone, the operation time increased by 71.4% and 100% after the addition of optimum dosage of powder activated carbon or iron salts. Moreover, although the microorganisms in the membrane tank were inactivated by chlorination pretreatment, the membrane fouling was alleviated to a certain extent. For the effluent quality, the average effluent turbidity of the integrated iron-based-floc-UF process was lower than 0.1 NTU, and the iron concentration was lower than the national standard (GB5749-2006). The removal rates of total organic carbon, total phosphorus and ammonia nitrogen also increased to some extent.
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