AWWA WQTC64079

AWWA WQTC64079 Exploration of Membrane Bioreactor Use for DBP Control
Conference Proceeding by American Water Works Association, 11/01/2006

Stile, Julianne; Cole, Charles; Xie, Yuefeng

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This study was conducted to determine if the use of membrane bioreactors (MBRs) may be feasible for thetreatment of drinking water to control disinfection byproduct (DBP) formation. The study evaluated the removalof precursors in both groups of regulated organic DBPs, trihalomethanes (THMs) and haloacetic acids(HAAs). In order to determine if it is possible for reactor biomass to be supported by the organicloading of a source water, a synthetic water made of powdered milk and micronutrientswas used as the MBR influent. Fresh influent was made every 24-36 hours. Thesynthetic water was started at a chemical oxygen demand of 200 mg/L, which wasequivalent to that of the feed into a local municipality's activated sludge tank. Thiscorresponded to an initial total organic carbon (TOC) concentration of about 30 mg/L. The synthetic waterinfluent concentration was lowered twice after a stabilization period ranging from acouple weeks to a couple months, to an influent TOC concentration of approximately 19mg/L then to approximately 10 mg/L. The 10 mg/L concentration was starting to getclose to the TOC range of a high TOC drinking water source.An immersed hollow fiber membrane bench scale reactor was constructed out of clearacrylic with a volume of 1.8 L. The membrane had an area of 0.03 msup2/sup and a porosity of0.4 microns. The membrane flux was kept at approximately 0.45 msup3/sup/d/msup2/sup. The reactorwas seeded with activated sludge from the local wastewater treatment plant. Due tosignificant membrane fouling, powdered activated carbon (PAC) was also added after the first couple days at an initialconcentration of 0.8 g/L. In order to determine the DBP precursor removal, effluent andinfluent were chlorinated and total trihalomethanes (TTHM) and the five regulated HAAs(HAA5) were analyzed after a 24 hour incubation period. The detailed experimentalconditions have been reported by Stile (2006). Includes 4 references, table.