Characterizing and modeling hydrogen sulfide production in anaerobic digestion of livestock manure, agro‐industrial wastes, and wastewater sludge
Sarah E. Daly, Ji‐Qin Ni
Abstract
Abstract Hydrogen sulfide (H 2 S) is the most undesirable inorganic gas in biogas from anaerobic digestion (AD). However, H 2 S production in AD is complex and understanding of its processes is still limited. This study performed six controlled batch anaerobic co‐digestion experiments to investigate H 2 S production. Materials were obtained from four field anaerobic digester systems and co‐digestion feedstocks from agroindustry. An additional precipitation experiment was conducted to further examine H 2 S production dynamics. Digesters containing highly soluble, carbohydrate‐based wastes had a high H 2 S final specific production (FSP) value. Additionally, the FSP values were negatively correlated with the initial Fe(II):S ratios in the digester liquid of the batch tests. The precipitation experiment indicated that iron sulfide precipitation was preferred in the presence of an anaerobic community. The H 2 S production as a time series was successfully modeled using a generalized additive model ( R 2 > 0.82). This study revealed that sulfate, phosphorus, and iron concentrations are important predictors and potential inhibitors of H 2 S production in AD. Further examination of real‐time H 2 S modeling in AD is warranted.