Biogas biodesulfurization in an anoxic biotrickling filter packed with open-pore polyurethane foam

Biogas biodesulfurization by an anoxic biotrickling filter packed with open pore polyurethane foam at the laboratory scale (packed volume 2.4 L) has been studied. The biotrickling system was operated for 620 days with biogas supplied continuously and two nitrate feeding regimes were tested (manual and programmed). Biomass immobilization was carried out under the manual nitrate feeding regime and a study was then carried out on the effects on removal efficiency of the following parameters: nitrate source, H2S inlet load, nitrate concentration, sulfate accumulation, temperature, pH and trickling liquid velocity. The effect of increased H2S inlet load was studied under the programmed nitrate feeding regime. The results show that a removal efficiency of 99% can be obtained when working under the following conditions: inlet loads below 130 gS m−3 h−1, a programmed nitrate feeding system, temperature of 30 °C, sulfate concentration below 33 g L−1, a pH between 7.3 and 7.5, and a trickling liquid velocity higher than 4.6 m h−1.