WRA Presented at the 2015 Tri-Association Conference.
Baltimore, MD – The Chesapeake Water Environment Association (CWEA), the Chesapeake Section, American Water Works Association (CSAWWA), and the Water & Waste Operators Association of MD, DE, and DC (WWOA) hosted a combined Tri-Association Conference and Exhibition (TRICON) at the Roland E. Powell Convention Center in Ocean City, Maryland from September 1–4, 2015.
Mike Bezanson, P.E and Senior Project Engineer at WRA, spoke about Biogenic Sulfide Corrosion in connection with Baltimore City’s Back River Wastewater Treatment Plant. His presentation identified and described remediation measures considered and selected in the rehabilitation of the primary treatment settling tanks.
Biogenic sulfide corrosion was explained as a microbial process where hydrogen sulfide is formed and then oxidized by bacteria creating sulfuric acid. The sulfuric acid attacks and damages concrete and steel surfaces within areas susceptible to biogenic corrosion.
Biogenic sulfide corrosion was present at Back River Wastewater Treatment Plant within the primary treatment settling tanks and repaired under Baltimore City Sanitary Contract 829. The damaged portions of the tanks were repaired utilizing a simple concrete mix with a low water to cement ratio. The result created a high-density concrete substrate without the use of expensive or proprietary mixes and additives. The finished concrete surfaces within highly corrosive areas were then properly prepared to allow for maximum adhesion of an epoxy coating system to minimized future biogenic sulfide corrosion.
Biogenic sulfide corrosion is a potentially damaging issue, and remediation measures should be considered whenever working within confined or turbulent areas where corrosive gas is able to collect above the surface of sewage.