title: Identification of biofoulant of membrane bioreactors in soluble microbial products.
abstract: To reveal primary biofoulant in soluble microbial products (SMP) and/or soluble extracellular polymeric substances (EPS), after removal of sludge particles, activated sludge samples were subjected to microfiltration tests in a submerged MBR. Filtration resistance directly correlates with the saccharide concentration. Saccharides in wastewater from several sources contained uronic acids, which increased the filtration resistance. When the microfiltration test liquids contained saccharides over 80mg l(-1), a gelatinous mass remained on the membrane surface after filtration and contained concentrations of saccharides and uronic acids 50 times higher than the original test liquid while only trace amounts of these substances were contained in the filtrate. The gelatinous mass contained high molecular weight substances of 10(6)-10(8)Da, suggesting the presence of polysaccharides. However, molecules of this size were calculated to be much smaller than the pore size of the membrane. Ethylenediaminetetraacetic acid decreased filtration resistance, suggesting that polysaccharides containing uronic acid units could undergo intermolecular or intramolecular ionic cross-linking by polyvalent cations and form the gel, thus clogging the membrane pores as an actual biofoulant.
authors: Microza & Water Processing Division, Asahi Kasei Chemicals Co., Ltd., Fuji, Shizuoka 416-8501, Japan.
authors: Daisuke
authors: D
authors: Okamura
authors: Yoshihiko
authors: Y
authors: Mori
authors: Tomotaka
authors: T
authors: Hashimoto
authors: Katsutoshi
authors: K
authors: Hori
mesh_terms: D019149:Bioreactors; D002241:Carbohydrates / Q000032:analysis; D004492:Edetic Acid / Q000737:chemistry; D005374:Filtration; D008567:Membranes, Artificial; D010316:Particle Size; D013499:Surface Properties
chemical_list: D002241:Carbohydrates; D008567:Membranes, Artificial; D004492:Edetic Acid