Treatment Plant Operator Exam Study Guide Answers

Hydrogen sulfide is oxidized to sulfuric acid by what bacteria, common in pipe walls in collection systems and lift station wet wells? The answer to the question is B, Thiobacillus. Hydrogen sulfide has a lifecycle that goes from liquid to gas to liquid in certain conditions. Sulfates present in the wastewater are changed to sulfide by bacteria in waterline slime layers. The flow splash and turbulence caused the H2S gas to release. The gas is then oxidized by the Thiobacillus bacteria to sulfuric acid, a corrosion cause, drips down the pipes where it changes back to sulfate in the wastewater stream.