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Project ID: 2006HI159B

Title: Identification and control of membrane bioreactor biofouling organisms using genetic fingerprinting

Project Type: Research

Start Date: 03/01/2006

End Date: 02/28/2007

Congressional District: HI 1st

Focus Categories: Water Supply, Treatmen, Economics

Keywords: membrane bioreactor, biofouling, genetic fingerprinting, economics

Principal Investigator: Babcock, Roger (University of Hawaii)

Federal Funds: $27,809

Non-Federal Matching Funds: $55,601

Abstract: Membrane bioreactors (MBRs) are a relatively new wastewater treatment technology which combines several typical unit operations (primary sedimentation, activated sludge aeration and sedimentation, and tertiary media filtration) into a single treatment step. This allows production of water suitable for recycling (unrestricted use) in a simple and compact system consisting of only a fine screen, an MBR, and a reduced-strength disinfection system. Like other membrane systems but to a greater degree, MBRs are susceptible to biofouling. Biofouling is not well understood but does increase operating pressure, reduce maximum flux (water passed through the membrane), increase recovery cleaning requirements, and possibly reduce total membrane life. All of these effects of biofouling have adverse effects on either initial capital cost or ongoing operation and maintenance costs for MBRs. The overall goal of this research will be to obtain a better understanding of biofouling in MBRs and methods to control said fouling in order to improve the economics of water recycling. The study will include long-term operation of two bench-scale MBRs under different conditions and evaluating membrane biofouling as a function of microbial population analysis using genetic fingerprinting. Biofouling will simultaneously be related to various water quality and operational parameters such and transmembrane pressure (TMP), biofilm thickness, soluble microbial products (SMP), extracellular polymeric substances (EPS), viscosity, particle size distribution (PSD), soluble COD, and sludge filterability. Pilot scale MBRs operated for a separate project will also be sampled as well as full-scale conventional activated sludge systems for comparisons. The various findings will be evaluated and relationships determined between microbial speciation, and resultant water quality parameters and membrane fouling states. This information will be integrated into a chart/decision-tree format useful for predicting fouling conditions as a function of operating parameters and based on dominant bacteria species. The 20-year life-cycle MBR system costs associated with different fouling states will be estimated and integrated into a separate chart/graph which can then be used to determine the most economical operating conditions for water recycling.

Progress/Completion Report, PDF

U.S. Department of the Interior, U.S. Geological Survey
Maintained by: John Schefter
Last Updated: Friday, January 29, 2010
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