Empirical modelling and dual-performance optimisation of a hydrogen sulphide removal process for biogas treatment

This study was conducted in order to investigate the use of a simple, low-cost technology for the removal of hydrogen sulphide (H2S) from biogas, consisting of an anoxic biotrickling filter. Modelling and optimisation of the process was achieved by studying two independent variables (H2S concentration and biogas flowrate) and two simultaneous performance criteria (H2S removal efficiency (%) and H2S loading rate (g/(m3 bed day)), which were inversely related. The experiments were carried out on a bioreactor with a 12 L packing volume. H2S concentration and biogas flowrate were varied in the range of 2000–4000 ppmv and 10–70 L/h, respectively. A model sensitivity analysis indicated the influence of the process variables on the bioreactor performance. Process optimisation was undertaken on a H2S removal efficiency basis, while maintaining a target H2S loading rate, depending on the desired quality for the biogas use and the technological requirements.