Why does H2S form?

H2S is created when the following conditions are present; limited and/or no oxygen is present (anaerobic), a very acidic environment, the presence of sulphate-reducing bacteria, and an ample supply of organic matter generally elemental Sulphur with free hydrogen. The biological activity of anaerobic sulphate-reducing bacteria generate usable energy under low-oxygen conditions by using sulphates (resp. elemental sulphur) to oxidize organic compounds or hydrogen; this produces hydrogen sulphide as a waste product which results in the formation of hydrogen sulphide and is released into the atmosphere as a gas. This gas mixes with moisture forms sulfuric acid. The sulfuric acid is very corrosive and attacks exposed concrete and accelerates the rusting/corrosion of any exposed metal H2S or solutions containing H2s come into contact with.

What condition causes the formation of H2S?

In general terms, H2S can form in any environment that possesses all of the following conditions; acidic, anaerobic, high Sulphur presence with organic matter, hydrogen, and sulphate reducing bacteria. When these conditions are present, the hydrolysis of anaerobic bacteria reduce the sulphate ion (SO2) to sulphide (S2-) then join with hydrogen ions creating H2S. What takes place next? The hydrogen sulphide separates, depending on pH, to dissolved hydrogen sulphide gas (H2S), hydrosulphide ion (SS-) and sulphide ion S2-). At a pH of 7, the mixture is approximately 50% H2S and 50% HS-. At pH 6, the mixture is approximately, 90% dissolved hydrogen sulphide gas and 10% hydrosulphide ion.

Is H2S corrosive or toxic?

The released H2S mixes with moisture on the exposed surfaces of pipes, tanks, manholes, etc. above the waterline, and forms sulfuric acid. The pH, progressively falling, will allow acid tolerant species of aerobic bacteria to form on the surfaces as additional sulfuric acid is formed. This acid is highly corrosive on concrete and many other metal surfaces. Further, the build-up of H2S gas in holding tanks or after agitation is highly toxic and can easily be lethal if left untreated at very low levels.

How Can We Correct H2S in Water?

3 Tier’s PWT-1000 is our answer to H2S elimination. This product uses a proprietary blend of PEB with a specially formulated amino acid/enzyme combination. These multi-function natural products not only eliminate existing H2S, they also alter the environment making further H2S development virtually impossible. Existing H2S is treated by reversing the acidic cations by our alkali-based products that not only bind protons but fracture the sulphide/hydrogen bonds through highly effective oxidation of H2S into elemental Sulphur and hydrogen which results in the reduction or elimination of existing H2S. The products further alter the environment by increasing the Oxygen Redox Potential (ORP) which moves the environment from anaerobic to facultative and possibly aerobic, catalyse and oxidize organics while maintaining Sulphur and sulphates in an elemental forms, and naturally buffers the environment allowing for long term stability which eliminates any future development of H2S.

If you have any questions about Environmental Intelligence or 3 Tier Technology products please call us on +61 3 9325 3650

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