Hydrogen Sulfide (H2S) and Bacteria

Hydrogen Sulfide (H2S) and Bacteria


It is well known that wastewater and sewage has a very high potential to produce nasty odors such as hydrogen sulfide (H2S, ammonia, indoles, skatoles and mercaptans. Of these hydrogen sulfide (H2S) is arguably the most import mainly due to



A van der Waals' surface coloured according to...
A van der Waals’ surface coloured according to charge, superimposed on a ball-and-stick model of the hydrogen sulfide molecule, H 2 S. Red represents partially negatively charged regions, blue represents partially positively charged regions, and white represents neutral (uncharged) regions. Created in Accelrys DS Visualizer 1.5, edited with Photoshop Elements 3.0. (Photo credit: Wikipedia)



toxicity, its ability to corrode materials, and it is the major source of odor problems at wastewater treatment facilities, manholes, and lift stations. The conditions leading to hydrogen sulfide formation favor the production of other odiferous organic compounds. So solving an H2S odor problem can often solve other wastewater odor problems as well.

Sources of Hydrogen Sulfide in Wastewater


Sulfur is present in both human and livestock solid wastes and sulfates are found in most water supplies. Almost all wastewater has a sufficient amount of sulfur for both anaerobic bacteria and facultative bacteria to produce hydrogen sulfide.

Generally, these bacteria produce H2S as a byproduct of their metabolism. By a process called anaerobic respiration, anaerobic bacteria oxidize organic compounds while reducing sulfate (SO4) to hydrogen sulfide (H2S). Interestingly, sulfate reducing bacteria are considered one of the oldest forms of life on earth. They are some 3.5 billion years old.

Hydrogen Sulfide Production Rate

The rate that anaerobic bacteria produce hydrogen sulfide in wastewater collection streams is dependent on a number of factors. Generally, H2S is produced in a slime layer on collection pipes at a rate controlled by:

  • Temperature
  • Concentrations of organic matter and nutrients
  • Sulfate concentration
  • Retention Time
  • pH
  • Sulfate Concentration
  • Stream Velocity
  • Surface area

Desulfovibrio desulfuricans

The most common hydrogen sulfide producing anaerobic bacteria in wastewater facilities is Desulfovibrio desulfuricans. Generally found in the slime layer in wastewater pipes, this bacteria is an obligate anaerobe. Desulfovibrio desulfuricans use sulfate as their oxygen source and ammonia as their sole source of nitrogen.

Fortunately, these bacteria can not compete with the bacteria in F-TREAT by Custom Biologicals. F-TREAT contains facultative anaerobic bacteria. These bacteria, because of their biochemistry, reproduce at a faster rate than the Desulfovibrio bacteria. By the process of competitive inhibition, F-TREAT replaces the hydrogen sulfide producing bacteria, thereby reducing sewage odors, wastewater problems and hydrogen sulfide issues.

Contact Custom Biologicals for more information about how to control hydrogen sulfide odors and other wastewater odors at your sewage treatment plant, wastewater treatment facility, or lift station.

Custom Biologicals can be reached at (561) 797-3008 or via email at Bill@Custombio.biz.

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