Biodegradation of sulphide in biogas by biofilm on salak fruit seeds: The effect of intra-film-gradient

Elimination of H2S in biogas was performed by bio-filtration, in which H2S degrading bacteria immobilized on the packing material inside a column. Bacteria was taken from the local area, while salak fruit seed was used as packing material because it has a quite large carbon content, porous and has a high water absorption capability. To obtain a quantitative description of the process, which is useful in the design of large-scale bio-filters, two kinetics models were proposed. Model 1 assumes intra-film gradient does not exist and the gas phase is quasi-steady-state. Model 2 assumes intra-film gradient exists and the gas phase is quasi-steady-state. Comparison of the calculation results using the two models to the experimental data suggested the use of model 2. This conclusion is based on both the trend and the accuracy. The trend of model 1 is more conceivable. However, for rough calculation, model 1 could be used for the reason that it is simpler than model 2. The average absolute errors of model 1 and 2 are comparable, approximately 6 ppm. It can also be concluded that intra-film gradient significantly affects the overall rate processes, while the gas phase can be assumed to be quasi-steady-state