Influence of shear on EPS production in membrane bioreactors

ENVR 94

Adrienne L. Menniti, menniti@uiuc.edu1, Seoktae Kang, seoktae.kang@yale.edu2, Menachem Elimelech, menachem.elimelech@yale.edu2, and Eberhard Morgenroth, emorgenr@uiuc.edu1. (1) Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 4125 Newmark Civil Engineering Laboratory, MC-250, 205 North Mathews Avenue, Urbana, IL 61801, (2) Department of Chemical Engineering, Environmental Engineering Program, Yale University, Mason Laboratory 204, 9 Hillhouse Ave., New Haven, CT 06520
Shear, in the form of air scour, is used to control fouling in MBRs. However, shear also affects the physical and physiological properties MBR biomass. The current study examines biological adaptation to increased shear. Two identical MBRs are operated in parallel with differing air scour rates. The concentration and composition of floc-associated EPS is compared. The production and degradation of soluble EPS is also evaluated. Atomic force microscopy is used to compare EPS properties by measuring the interaction forces between EPS molecules and carboxylate functional groups. Shortly after increasing the air scour rate, the soluble EPS concentration increases while the floc-associated EPS concentration decreases due to the erosion of floc-associated EPS compounds. Preliminary results suggest that the organisms adapt to the shear-induced removal of floc-associated EPS by producing EPS with greater carboxylate interaction forces. This shift toward stickier EPS is coupled with a decrease in the floc-associated EPS production rate.
 

Membrane Technology for Water Treatment and Reuse
1:30 PM-5:10 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 237, Oral

Division of Environmental Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008