Vinyl chloride removal from an air stream by biotrickling filter.

A biofiltration process was used for degradation of vinyl chloride as a hazardous material in the air stream. Three biotrickling filters in series-parallel allowing uniform feed and moisture distribution all over the bed were used. Granular activated carbon mixed with compost was employed as carrier bed. The biological culture consisted of mixture of activated sludge from PVC wastewater treatment plant. Concurrent flow of gas and liquid was used in the bed. Results indicated that during the operation period of 110 days, the biotrickling bed was able to remove over 35% of inlet vinyl chloride. Maximum elimination capacity was calculated to be 0.56 g.m(-3).hr(-1). The amount of chlorine accumulated in the circulating liquid due to the degradation of vinyl chloride was measured to be equal to the vinyl chloride removed from the air stream.

Influence of temperature on process efficiency and microbial community response during the biological removal of chlorophenols in a packed-bed bioreactor.

Two reactors, initially operated at 14 and 23+/-1 degrees C (RA and RB, respectively), were inoculated with a bacterial consortium enriched and acclimatized to the respective temperatures over 4 months. The biofilms, formed in the reactors, were studied using scanning electron microscopy, cultivation of the biofilm microflora, and physiological analysis of the isolates. Two bacteria able to mineralize chlorophenols under a large range of temperature (10-30 degrees C) were isolated from the biofilm communities of reactors RA and RB and characterized as Alcaligenaceae bacterium R14C4 and Cupriavidus basilensis R25C6, respectively. When temperature was decreased by 10 degrees C, the chlorophenols removal capacity was reduced from 51.6 to 22.8 mg l(-1) h(-1) in bioreactor RA (from 14 to 4 degrees C) and from 59.3 to 34.7 mg l(-1) h(-1) in bioreactor RB (from 23+/-1 to 14 degrees C). Fluorescence in situ hybridization (FISH) of the biofilm communities showed that, in all temperatures tested, the beta-proteobacteria were the major bacterial community (35-47%) followed by the gamma-proteobacteria (12.0-6.5%). When the temperature was decreased by 10 degrees C, the proportions of gamma-proteobacteria and Pseudomonas species increased significantly in both microbial communities.