the effects of soluble microbial products on membrane fouling of hollow fibers

background: soluble microbial products (smps) have an effective role on fouling of membrane in bioreactors (mbrs). the aim of this study was to survey the role of smps on mbrs used in treating municipal wastewater. materials: lowry and phenol sulfuric acid methods were used to measure carbohydrates concentrations and protein content, respectively. biochemical oxygen demand (bod), chemical oxygen demand (cod), suspended solids (ss), and turbidity tests were also performed according to standard methods for water and wastewater examinations. moreover, transmembrane pressure (tmp) was recorded at different times of operation. findings: concentrations of carbohydrate and protein extracted from the sludge supernatant were 3-8 mg/l and 2.5-7.6 mg/l, respectively. mixed liquor suspended solids (mlss) in the bioreactor were in the range of 0.6-3 g/l. turbidity and ss of the bioreactor effluent were 0.5 ntu and 5 mg/l, respectively. conclusion: extracted carbohydrate from supernatant plays a more important role than extracted protein in biological membrane fouling of mbrs.