title: A new insight into membrane fouling mechanism in submerged membrane bioreactor: osmotic pressure during cake layer filtration.
abstract: Big gap between experimental filtration resistance of cake layer formed on membrane surface and the hydraulic resistance calculated through the Carman-Kozeny equation, suggested the existence of a new membrane fouling mechanism: osmotic pressure during cake layer filtration in SMBR system. An osmotic pressure model based on chemical potential difference was then proposed. Simulation of the model showed that osmotic pressure accounted for the major fraction of total operation pressure, and pH, applied pressure and ionic strength were the key determining factors for osmosis effect. It was found that, variations of osmotic pressure with pH, applied pressure and added ionic strength were well coincident with perditions of model's simulation, providing the first direct evidences of the real occurrence of osmosis mechanism and the feasibility of the proposed model. These findings illustrate the essential role of osmotic pressure in filtration resistance, and improve fundamental understanding on membrane fouling in SMBR systems.
authors.affiliation: College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China.
authors.forename: Meijia
authors.initials: M
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Peng
authors.forename: Jianrong
authors.initials: J
authors.lastname: Chen
authors.forename: Yiming
authors.initials: Y
authors.lastname: He
authors.forename: Linxian
authors.initials: L
authors.lastname: Ding
authors.forename: Aijun
authors.initials: A
authors.lastname: Wang
authors.forename: Hongjun
authors.initials: H
authors.lastname: Lin
authors.forename: Huachang
authors.initials: H
authors.lastname: Hong
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.forename: Haiying
authors.initials: H
authors.lastname: Yu
mesh_terms: D019149:Bioreactors; D003198:Computer Simulation; D005374:Filtration; D006863:Hydrogen-Ion Concentration; D007834:Lasers; D008962:Models, Theoretical; D009995:Osmosis; D009997:Osmotic Pressure; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis; D011108:Polymers / Q000737:chemistry; D011312:Pressure; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: D052638:Particulate Matter; D011108:Polymers