What creates hydrogen sulfide?

Hydrogen sulfide is primarily produced by the decomposition of organic matter in environments where oxygen is limited or absent, a process known as anaerobic decomposition. When organic material decays without oxygen, sulfate-reducing bacteria play a crucial role by breaking down the compounds and reducing sulfates to hydrogen sulfide gas. This occurs in environments such as swamps, sewers, and septic tanks, where organic matter accumulates and oxygen levels are low, making anaerobic conditions favorable for these bacteria.

In contrast, aerobic decomposition occurs in the presence of oxygen and typically results in the production of carbon dioxide and water, rather than hydrogen sulfide. Chemical reactions with sulfates may produce hydrogen sulfide under specific conditions, but the direct source of hydrogen sulfide in wastewater treatment primarily stems from anaerobic decomposition. Microbial oxidation refers to the process by which bacteria oxidize substrates for energy, which can involve aerobic processes but does not contribute specifically to the formation of hydrogen sulfide.