International audienceBACKGROUND: This study deals with the potential of biological processes combining biofiltration and a biotrickling filter to treat a mixture of sulphur reduced compounds (SRC) including dimethylsulfide (DMS), dimethyldisulfide (DMDS) and hydrogen sulphide (H2S). The first step in this work is to evaluate the influence of pH on SRC biodegradation in microcosms seeded with planktonic biomass from activated sludge of a rendering facility. In a second step, for each tested pH, evaluation of the influence of pH on total bacterial community diversity and structure has been investigated using denaturing gradient gel electrophoresis (DGGE). RESULTS: At pH 7 and 5, H2S, DMS and DMDS were completely removed. In return, the abatement of DMS and DMDS is low, around 20%, for pH 3 and pH 1 microcosms. The selective pressure imposed in the microcosms (concentration and pH) is sufficient to influence strongly the community diversity and composition. The inoculum community seems to make a significant contribution to the 67-day community in the considered pH microcosms. CONCLUSION: These results suggest that distinct communities from different inocula can achieve high and stable functionality. The results obtained provide relevant information for improving the treatment of different SRC using biotrickling filter/biofilter combination. Copyright (c) 2012 Society of Chemical Industr

This study deals with the potential of biological processes combining a biotrickler and a biofilter to treat a mixture of sulphur-reduced compounds including dimethyl sulphide (DMS), dimethyl disulphide (DMDS) and hydrogen sulphide (H2S). As a reference, duplicated biofilters were implemented, and operating conditions were similar for all bioprocesses. The first step of this work was to determine the efficiency removal level achieved for each compound of the mixture and in a second step, to assess the longitudinal distribution of biodegradation activities and evaluate the total bacteria, Hyphomicrobium sp. and Thiobacillus thioparus densities along the bed height. A complete removal of hydrogen sulphide is reached at the start of the experiment within the first stage (biotrickler) of the coupling. This study highlighted that the coupling of a biotrickling filter and a biofilter is an interesting way to improve both removal efficiency levels (15-20% more) and kinetics of recalcitrant sulphur compounds such as DMS and DMDS. The total cell densities remained similar (around 1 × 10(10) 16S recombinant DNA (rDNA) copies g dry packing material) for duplicated biofilters and the biofilter below the biotrickling filter. The relative abundances of Hyphomicrobium sp. and T. thioparus have been estimated to an average of 10 ± 7.0 and 0.23 ± 0.07%, respectively, for all biofilters. Further investigation should allow achieving complete removal of DMS by starting the organic sulphur compound degradation within the first stage and surveying microbial community structure colonizing this complex system.