Electrochemical removal of hydrogen sulfide from swine manure

Hydrogen sulfide (H2S) produced in swine manure storage is a safety hazard to both humans and animals. An electrochemical treatment method based on low carbon steel electrodes was developed to reduce aqueous sulfide and emitted H2S concentration from manure storage. At the selected condition (applied voltage of 0.7 V, immersed electrode surface area of 19 cm2/L, initial sulfide concentration around 6 mM, and operating temperature of 19 °C), the process achieved an average sulfide removal rate of 0.97 mg S2−/(cm2·day) for the zero order kinetics model, and a rate coefficient of 0.267/day for the first order kinetics model. The electrical charge consumption was 5.26 C/mg S2−. With the removal of over 90% (95% maximum) of sulfide and H2S, the risk of massive release of H2S can be significantly reduced. The installation of this treatment technology may reduce the risk of manure pump-out in terms of H2S over-exposure and may be applied in similar circumstances where H2S poses threats to health and life.