The start-up period of styrene degrading biofilters.

Styrene vapors from contaminated air were eliminated using long-term adapted mixed microbial culture inoculated on four perlite packed biofilters (serial arrangement, up-flow configuration). During start-up the inlet concentration of styrene rose from 175 to 1300 mg/m3 of total carbon. The total actual residence time in the four biofilters was 24 s. Styrene was successfully degraded by the microbial population in the biofilter. An average of 66% of eliminated styrene was transformed to CO2. The removal efficiency of the pollutant was, after 18 d of start-up, nearly 85% at an organic load of 170 g/m3 per h. The concentration profiles along the bed height were linear for various pollutant inlet concentrations. The total amount of microorganisms in analyzed biomass from the biofilters was about 10(9) per gram of dry packing mass. The moisture content was around 80% in all biofilters.

Effect of pH and loading manner on the start-up period of peat biofilter degrading xylene and toluene mixture.

Laboratory-scale biofilters packed with a mixture of peat, bark and wood were used for xylene and toluene removal from waste air. Two kinds of peat, which differed in the resulting pH of the leachate, were chosen for degradation of the pollutants by a mixed culture. Using peat with the lower pH value, the feasibility of single and multiple pollutant loading during the start-up period and augmentation with Pseudomonas putida strains were characterized. The lower pH value of the bed resulted in higher efficiency of toluene degradation from the mixture of pollutants. At higher pH values better degradation of both pollutants was achieved. Regarding the manner of loading during the start-up period, the best results were obtained using toluene as a single pollutant in the initial phase of operation. Pseudomonas strains demonstrated a high ability to degrade both pollutants; more efficient degradation for xylene than for toluene was observed at high loading rates.