Compounds interaction on biodegradation of toluene and methyl ethyl ketone mixtures in a composite biofilter

Abstract

Compounds interaction on biodegradation of toluene and methyl ethyl ketone (MEK) mixtures in a composite bead biofilter was investigated. The biodegradation rate of two compounds in the exponential growth phase and stationary phase for the single compound and two compounds mixing systems was determined. For the single compound system, the  biodegradation rate of two compounds in the microbial growth phase and stationary phase was inhibited with increasing inlet compound  concentration. The inhibitive effect resulting from increasing the inlet compound concentration was predominated at higher inlet compound concentrations. For the two compounds mixing system, the microbial metabolic activity of biodegraded toluene in the microbial growth process and biochemical reaction process was inhibited as MEK was introduced. The inhibitive effect resulting from compounds interaction was more  pronounced at higher inlet concentrations of both compounds. The  maximum elimination capacity of toluene was reduced as MEK was  introduced and that of MEK was not affected as toluene was introduced. Increasing concentration of MEK in the influent mixture strongly  suppressed the biodegradation efficiency of toluene, while increasing concentration of toluene in the influent mixture had no effect on the biodegradation efficiency of MEK.

Key words: Toluene, methyl ethyl ketone, biodegradation, compounds interaction, composite bead biofilter.