Effects of Kraft evaporator condensate matrix on methanol removal in a high temperature membrane bioreactor

The removal of methanol from kraft pulp mill condensate using a high temperature membrane bioreactor (MBR) was studied. The effects of the condensate matrix on methanol metabolism and removal kinetics were investigated by varying the fraction of the real condensate in the feed for 0-100 per cent. The methanol removal rate followed first-order kinetics. The condensate matrix reduced the specific methanol utilization rate in the MBR. Tests were conducted to investigate whether the contaminants present in the real condensate matrix inhibited a mixed culture acclimated to synthetic condensate only and whether additional, non-methanolic substrates in the real condensate matrix changes the composition of the microbial community in the MBR. Contaminants in the real condensate matrix did not reduce the observed specific methanol utilization rate. The reduction in the specific methanol utilization rate was caused by a shift in the composition of the microbial community in the MBR, resulting from composition between non-methylotrophic and methylotrophic microorganisms for the available methanol.