Membrane flux dynamics in the submerged ultrafiltration hybrid treatment process during particle and natural organic matter removal
Author(s): Wei Zhang1, 2, Xiaojian Zhang1, Yonghong Li1, Jun Wang1, Chao Chen1, * 1. Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China. 2. Beijing Special Engineering Design and Research Institute, Beijing 100028, China
Pages: 1970-1976
Year: 2011 Issue: 12
Journal: Journal of Environmental Sciences
Keyword: ultrafiltration; membrane flux; particles; natural organic matter; hybrid process; backwashing;
Abstract: Particles and natural organic matter (NOM) are two major concerns in surface water, which greatly influence the membrane filtration process. The objective of this article is to investigate the effect of particles, NOM and their interaction on the submerged ultrafiltration(UF) membrane flux under conditions of solo UF and coagulation and PAC adsorption as the pretreatment of UF. Particles, NOM andtheir mixture were spiked in tap water to simulate raw water. Exponential relationship, (JP/JP0 = a×exp{-k[t-(n-1)T]}), was developedto quantify the normalized membrane flux dynamics during the filtration period and fitted the results well. In this equation, coefficienta was determined by the value of JP/JP0 at the beginning of a filtration cycle, reflecting the flux recovery after backwashing, that is, theirreversible fouling. The coefficient k reflected the trend of flux dynamics. Integrated total permeability (ΣJP) in one filtration periodcould be used as a quantified indicator for comparison of different hybrid membrane processes or under different scenarios. Accordingto the results, there was an additive eflect on membrane flux by NOM and particles during solo UF process. This additive foulingcould be alleviated by coagulation pretreatment since particles helped the formation of flocs with coagulant, which further delayedthe decrease of membrane flux and benefited flux recovery by backwashing. The addition of PAC also increased membrane flux byadsorbing NOM and improved flux recovery through backwashing.
Pages: 1970-1976
Year: 2011 Issue: 12
Journal: Journal of Environmental Sciences
Keyword: ultrafiltration; membrane flux; particles; natural organic matter; hybrid process; backwashing;
Abstract: Particles and natural organic matter (NOM) are two major concerns in surface water, which greatly influence the membrane filtration process. The objective of this article is to investigate the effect of particles, NOM and their interaction on the submerged ultrafiltration(UF) membrane flux under conditions of solo UF and coagulation and PAC adsorption as the pretreatment of UF. Particles, NOM andtheir mixture were spiked in tap water to simulate raw water. Exponential relationship, (JP/JP0 = a×exp{-k[t-(n-1)T]}), was developedto quantify the normalized membrane flux dynamics during the filtration period and fitted the results well. In this equation, coefficienta was determined by the value of JP/JP0 at the beginning of a filtration cycle, reflecting the flux recovery after backwashing, that is, theirreversible fouling. The coefficient k reflected the trend of flux dynamics. Integrated total permeability (ΣJP) in one filtration periodcould be used as a quantified indicator for comparison of different hybrid membrane processes or under different scenarios. Accordingto the results, there was an additive eflect on membrane flux by NOM and particles during solo UF process. This additive foulingcould be alleviated by coagulation pretreatment since particles helped the formation of flocs with coagulant, which further delayedthe decrease of membrane flux and benefited flux recovery by backwashing. The addition of PAC also increased membrane flux byadsorbing NOM and improved flux recovery through backwashing.
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