ENHANCEMENT OF DISSOLVED ORGANIC MATTER REMOVAL IN DYNAMIC MEMBRANE REACTOR BY ATTAPULGITE ADDITION

摘要

Membrane bioreactor fouling is influenced not only by the concentration of dissolved organic matter but by its characteristics. This research examined the effect of atta-pulgite (AT) addition on dissolved organic matter (DOM) removal characteristics in a dynamic membrane bioreactor (DMBR). Results indicated the DOM in the attapul-gite-added DMBR system decomposed more rapidly than in the DMBR system. Hence, the attapulgite-added DMBR system had a higher DOM removal rate in term of dissolved organic carbon (DOC) concentration and UV254 concentration. Due to the hybrid effect of adsorption and co-precipitation on DOM after the addition of attapulgite, the characteristics of DOM in the two bioreactors differed considerably. The analysis of molecular weight distribution by gel permeation chromatography (GPC) showed that attapulgite-amended DMBR exhibited greater retention efficiency for large molecules than the DMBR without the addition of attapulgite. Attapulgite addition decreased hydrophilic compounds (HPI) concentration from 4.74 mg/L to 3.61 mg/L in the supernatant of attapulgite-added DMBR. Hydrophobic fractions of DOM showed little difference in concentrations in the effluent of two bioreactors. Bacterial community structures and abundances in membrane bioreactor were analyzed by polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The analyses indicate that there may be a link between the diversity and quantity of bacterial populations and DOM removal.