Control of dichloromethane emissions using biofiltration

Abstract

Inhibition has been observed in biofilters when multiple substrates are present in the inlet gases. This research evaluated the effects of toluene on the acclimation of microbial populations and biodegradation rate of dichloromethane in a compost biofilter. Experiments were performed in a laboratory scale biofiltration system. Greater than 98% removal efficiency was achieved for dichloromethane under the experimental conditions (1 min residence time and inlet concentrations of 3 and 40 ppm). Although acclimation to toluene occurred within two weeks of system start‐up, initial dichloromethane acclimation took place over a period of ten weeks. When a laboratory‐grown consortium of dichloromethane‐degrading organisms was introduced into fresh biofilter media, a 2–7 week acclimation period was still observed. The presence of toluene in the inlet gas stream inhibited dichloromethane degradation only when present at a high concentration. Overall dichloromethane removal remained constant as long as there was sufficient bed capacity.