The aim of this study was to develop a biofiltration system able to remove TCE from contaminated air and to optimize its operating conditions. Three types of one- and two-step installations were examined for the capacity to remove gas-phase trichloroethene from waste air. The immobilizate of the biomass active in TCE decomposition was used in the process. The efficiency of the process and metabolic activity of biomass were investigated.
The stable and effective biofiltration process was achieved when a two-step installation was used with hybrid bioreactor containing activated sludge suspension with active biomass immobilizate (bioscrubber) being the first step. The second step was a biofilter filled with traditional deciduous leaf debris compost mixed with wood chips and activated carbon. The efficiency of contaminant elimination achieved during 2.5 months of operation was between 52% and 92%. The bioscrubber activity in gas purification was high - even up to 76%, and biofilter capacity for contaminant elimination was in the range 65-88.3 g TCE/m³/h. Active strains of microorganisms selected in the course of the process were isolated and identified. Dominant bacteria belonged to the genus Streptomyces, Sarcina, Arthrobacter, Bacillus and also to Gramnegative rods from species Agrobacterium radiobacter and Sphingomonas paucimobilis. Moreover, two dominant strains of moulds and one strain of yeast were isolated from the biofilter-bed.