Abstract
Effect of soluble microbial products (SMP) on permeate flux in a cross-flow type ultrafiltration was investigated.
Synthetic wastewater (phenol) was continuously treated by an activated sludge process incorporating membrane solid-liquid separation. Hydraulic retention times and the sludge concentrations of the reactor were kept at 12 hours and 5,000 mg VSS·l-1, respectively. At certain intervals, batch filtration tests using mixed liquor of the reactor were conducted to investigate the mechanism of membrane fouling. The permeate flux dropped gradually, due to increase of SMP concentrations and of fouling mass adhered onto the membrane surface.
Batch phenol-degradation reactor and aerobic sludge digestion reactor were operated, and batch filtration tests were conducted to examine which type of SMP has more important role in flux drop. Higher flux drop was observed when the mixed liquor of the sludge digestion reactor was tested at a same level TOC concentrations of SMP. It was found by gel-chromatogram that high-molecular-weight SMP was dominant in the sludge digestion reactor. The results suggest that SMPe (SMP resulted from endogenous cell decomposition) has more significant effect on flux drop.
