The rate of concrete corrosion depends on the permeability of concrete and the amount of hydrogen sulfide gas that is adsorbed to the moist sewer walls (8). The cement that locks the sand and rock into place is vulnerable to the effects of H 2S gas and acid attack (5). Concrete – Concrete is a composite material made of sand, rock, and cement.The slime film creates an anaerobic environment that allows sulfide reducing bacteria (SRB) to thrive and they contribute to iron sulfide formation, which diminishes the protective oxide film on most stainless steels Stainless Steel – Even stainless steel is subject to corrosion by bacteria, especially if the bacteria are incorporated in a slime film attached to the metal.High amounts of sulfuric acid (results from oxidation of hydrogen sulfide by Thiobacillus) lowers the pH of wastewater and contributes to the deterioration of concrete and pipe corrosion (7). Rusted Pipe caused by Hydrogen Sulfide (H2S)Ĭorrosion of metal and concrete is a major issue associated with the generation and oxidation of hydrogen sulfide. For more information see our Hydrogen Sulfide Toxicity Chart. Although humans do possess biocatalysts in the liver that oxidize hydrogen sulfide to sulfate, high concentrations of hydrogen sulfide will overwhelm biocatalysts (3). The high toxicity associated with H 2S gas is due to its ability to bind to iron centers in mitochondrial cytochrome biocatalysts, which effectively stops cellular respiration and deprives essential organs of energy (3). Hydrogen sulfide is a toxic concern for wastewater operators, especially if odor-masking agents are used, since it can affect the nervous system causing headaches, nausea, irritation of the skin, eyes, and respiratory tract, and at high doses it can cause death (2, 3). This corrosion is often called Microbiologically Induced Corrosion (MIC) and can rapidly deteriorate cement and iron piping. These bacterial colonies tend to lower the pH and cause Thiobacillus to oxidize the H 2S and secrete sulfuric acid, causing corrosion. The process of hydrogen sulfide generation depends on pH, temperature, and reactant concentrations (11). Hydrogen sulfide gas in the sewer atmosphere may be adsorbed in the thin film of water that normally covers the sewer walls and may be partially oxidized to sulfuric acid by bacteria of the genus Thiobacillus (8).īacterial colonies and gas products are formed when bacteria in a wastewater system has favorable nutrient loadings and plenty of space above the water line. Our De-Sulph-A-Nator binds the sulfide and dissipate the odors over lift stations, wet wells, and sludge holding tanks, while OxyPaks XL disrupts the sulfur producing biofilm. H 2S can start to form sulfuric acid in lift stations and wastewater treatment plants, which will corrode cement and steel structures. When sewage becomes stagnant, H 2S gas is generated in the anaerobic conditions.

These sulfide-containing contaminants will either be oxidized (react with metals to form insoluble metal sulfides) or be released to the sewer (8, 13).

Decomposition of xanthates used in the mining industry (12).

Sulfide- Seen in tanneries and paper manufacturing.

Sulfate- Seen in sea food processing or fermentation plants.An industry can also generate sulfate/sulfide wastes that may contribute to sulfide levels in wastewater such as: It is also present in rainfall, primarily over metropolitans areas, but the most common source of sulfide is in domestic wastewater as sulfate. Sulfur is present in human and livestock waste as organic sulfides, such as mercaptans and disulfides. There are various problems associated with hydrogen sulfide generation, such as toxicity, noxious odors, and the generation of corrosive sulfuric acid. H 2S gas is highly poisonous and highly corrosive in wastewater applications. Hydrogen Sulfide (H 2S) often is a colorless gas with a rotten egg odor, which is commonly referred to as ‘sewer gas’.