Electrochemical mitigation of hydrogen sulfide in deep-pit swine manure storage

Highlights: • Electrochemical treatment was applied to mitigate H₂S release from swine manure. • Low carbon and stainless steel (LCS, SS304) were selected as effective electrodes. • H₂S removal efficiencies in lab-scale tests topped to 96% (LCS) and 100% (SS304). • Pilot-scale field test for 92 days yielded 84.0% (LCS) and 63.5% (SS304) H₂S removal. • An estimated annual cost of $13,821 was required for implementing this system. Hydrogen sulfide (H₂S) is a toxic and hazardous gas and is commonly present in livestock operations, which occasionally causes associated exposure accidents. This study evaluated the effectiveness of electrochemical control of H₂S in lab-scale swine manure storage using different electrode materials, and further selected suitable materials to demonstrate the performance of a pilot-scale field test in the deep-pit manure storage of a 200-head swine barn. In the lab-scale test, electrochemical sulfide oxidation mainly contributed to the H₂S mitigation, resulting in high H₂S removal efficiencies when using low carbon steel (LCS) and stainless steel 304 (SS304) as electrodes. Based on their better H₂S treatment performance and lower material costs, LCS and SS304 were selected for the pilot-scale test. In a 92-day operation, the pilot-scale demonstration showed H₂S removal efficiencies of 84.0% and 63.5% for LCS and SS304, respectively. A techno-economic assessment indicated that the installation and operation of the electrochemical system accounted for 16% of barn construction cost using LCS as electrodes. Further optimization may substantially decrease the electrode material consumption and the overall cost.