Character of Extracellular Polymeric Substances and Soluble Microbial Products and Their Effect on Membrane Hydraulics During Airlift Membrane Bioreactor Applications

The effect of extracellular polymeric substances and soluble microbial products developed from wastewater and mature landfill leachate biomass was assessed using a pilot-scale membrane bioreactor operating polymeric and ceramic air-lift sidestream multichannel membranes. The plant was operated under identical conditions of sludge retention time, system hydrodynamics, and parity of food-to-microorganism ratios. Biomass samples were extracted and fractionated ( fixed and bound material, carbohydrate and protein extracts) and chemically and physically analyzed with the feedwaters. Both ceramic and polymeric membranes were tested and the critical flux (J(C)) determined according to the classical flux-step analysis. Although permeability ( K) of both materials reduced with increasing flux (J), the ceramic material had a higher resistance to fouling, demonstrating a higher K ( by a factor of 1.2 and 3.2 for wastewater and leachate, respectively, at J of 30 L center dot m(-2) center dot h(-1)) and lower fouling rate (dP/dt) ( by more than an order of magnitude at the same J) than the polymeric membrane. Evidence suggests that deterioration of membrane permeability resulting from leachate biomass arises from the feedwater itself, rather than the products derived from the biomass, and that colloidal and/or soluble total organic carbon is primarily responsible for it. Water Environ. Res., 80, 2193 ( 2008).