Tackling Hydrogen Sulphide Degradation
Many wastewater plants suffer from the effects of hydrogen sulphide degradation.
In this article, Mark Lemon, Managing Director of CSC Services, looks at what it is and what can be done to protect assets from hydrogen sulphide degradation.
“Hydrogen sulphide results from septic conditions during the collection and treatment of wastewater. This colourless gas, known for its rotten egg smell, is produced by the biological reduction of sulphates and the decomposition of organic materials. It forms at virtually all points of a wastewater system from interceptors to holding tanks and drying beds, and is highly corrosive.”
Polyurea
Polyurea is a protective coating. It is highly resistant to hydrogen sulphide and hydrocarbons also commonly found in wastewater systems. It’s a highly elastic waterproof coating resistant to chemicals and abrasion.
Polyurea cures in seconds. It has rapid reuse times. When coated with polyurea systems, substrates such a concrete and steel can be submerged or buried. In contrast, traditional and even fast-cure epoxies can take a week to 10 days to completely cure.
Because of its elasticity, polyurea coatings are ideal for substrates such as concrete, which tends to crack. As an elastomer, these coatings have the ability to stretch and bridge gaps. Due to this flexibility, polyurea coatings are not limited by extremes of temperature, while rigid coatings tend to crack as the substrate expands or contract under these conditions.
Polyurea can be built to any thickness in one coat, so costs associated with application are reduced. Polyurea coatings also offer excellent adhesion. They are regularly tested up to 2,000 psi, compared with conventional epoxy coatings at 600-800 psi. Aliphatic polyurea coatings have exceptional UV light resistance, so they will withstand weathering and exposure to sunlight when applied to exterior surfaces.
DWI Approval
Clarifying agents, chemicals used for PH correction and disinfection in clean water tank structures also have damaging effects on concrete and steel structures. Polyurea is pending DWI approval, which will significantly open up opportunities to protect structures across the clean water sector in the near future.
Polyurea is an extremely versatile coating that has applications across industries. In the power sector, it can also be used to protect steel storage tanks, concrete bunds and internal and external pipework.