Sewage collection and treatment systems face very adverse conditions due to generation of Hydrogen Sulphide which combines with water vapour to produce Sulphuric Acid. The acid will corrode collection pipeline (crown areas), manholes and treatment plant structures like Digesters. The problem is acerbated by microbiologically induced corrosion (MIC).
Purethane coatings hold up very well to these environments. They have a long and successful track record in the sanitation industry.
Purethane will provide a lasting protective system to new concrete structures and concrete pipe. Typical structures include Bar Screen Area, Grit Chambers, Primary Clarifiers, Aeration Tanks, Digester Roofs, Gas Holders, Sludge Processing, Waste Tanks And Ponds.
Applied to existing structures deteriorated by hydrogen sulfide gases, the remaining concrete is protected from further corrosion. Deteriorating sewer trunk lines can be reclaimed by lining with Purethane coatings. Application of damp tolerant, penetrating sealing primer Purethane PIV effectively allows application on damp surfaces. In addition the hydrophobic nature and fast cure of Purethane coatings prevent reaction with atmospheric moisture after application.
Coatings intended for sewage applications need to possess high chemical resistance to withstand sulphur induced acidity as well as low permeability to prevent transmission of corrosive Hydrogen Sulfide through the coating film.
Very high elongation coatings such as 300% + Elongation Polyurethane & Polyurea coatings are NOT SUITED for this environment since they have lower chemical resistance and linear molecular structures with high permeability.