Odor and H2S · Where Wastewater Odors Come From
How Do Sulfate-Reducing Bacteria Make Sulfide in Wastewater?
Sulfate is a dissolved form of sulfur commonly present in wastewater. Under low-oxygen conditions, sulfate-reducing bacteria can use sulfate while breaking down organic matter. Their activity produces dissolved sulfide.
These bacteria often grow in slime layers on submerged pipe walls and in deposits. A slime layer, also called a biofilm, is a community of microorganisms attached to a wet surface. Deposits can provide both food and protected low-oxygen conditions.
Removing deposits, improving flow, or changing the available electron acceptor may reduce sulfide formation. An electron acceptor is a substance microbes use to complete the reactions that release energy from food. Results depend on the whole system, so operators should use monitoring data and work with their engineer and treatment supplier.
During inspections, note recurring deposits, stagnant areas, grease, and locations that remain submerged. Write down cleaning dates, material removed, flow patterns, and sulfide results. Alert maintenance and process staff if deposits return quickly or a change appears to move the problem downstream.
Key point: Sulfide production is a biological process favored by low oxygen, available sulfate, organic food, and time.
Keep learning
Odor Control and Hydrogen Sulfide (H2S) in Wastewater Systems
This page comes from the course. It covers where odors come from, hydrogen sulfide hazards, odor and H2S in collection systems, corrosion, gas detection and worker safety, and odor control in the collection system and at the plant, one step at a time, with short knowledge checks and a certificate of completion.
Take the course