抄録
This study examined the influence of operating conditions on membrane fouling in membrane bioreactors (MBRs) used for municipal wastewater treatment. Also, the mechanism of fouling evolution was investigated based on both pilot-scale and lab-scale experiments. Three pilot-scale MBRs were operated for about 100 daysat an existing municipal wastewater treatment facility. In the long-term operation, probably because aeration intensitywas enough to avoid formation of cake layer on the membrane surface, reversible fouling was not significant (i. e., irreversibletype of fouling dominated). The lab-scale experiments demonstrated that dissolved organic matter (DOM) accumulating in the reactors was likely to be responsible for the irreversible fouling. DOM loading on the membrane surface was found to influence the degree of total filtration resistance. It was revealed that changes in the composition of DOM (e. g., decrease in specific UV absorbance) in the reactors were also related to the irreversible fouling. Especially, dissolved sugar and dissolved protein contained in the mixed liquor played an important role in the development of the irreversible fouling.
