The McAlpine Creek Wastewater Management Facility (MCWWMF) is the largest wastewater treatment facility operated by Charlotte Water (CLTWater). In 2018, CLTWater began a Reliability and Process Improvements project. The project involved 16 secondary clarifiers that range from 95 to 150 feet in diameter, with the oldest clarifiers being nearly 60 years old.
CLTWater considered an epoxy coating. They had experience with epoxy coatings; however, they historically ran into issues with failures and delaminations. CLTWater opted to move forward with a pilot study with four different epoxy manufacturers. Three of the four manufacturers applied a test patch of their epoxy within the clarifier launder troughs. The team performed adhesion testing and analyzed the following variables: cost, schedule, performance, quality, service life, and safety. They determined Warren Environmental’s (Warren) 301-14 epoxy system was the best value for their project.
Warren’s epoxy was not the lowest cost option. Yet, based on the seven-month time savings, A&W Coatings’ single coat application of Warren’s epoxy provided the most cost savings. If CLTWater decided to use an alternative product, then the project may have incurred a delay due to the minimum cure time required of the product’s mortar underlayment. This delay would have resulted in additional overhead costs to CLTWater.
Another key benefit of Warren’s epoxy coating is its safety. All of their epoxies are free of volatile organic compounds (VOCs), solvents, styrene, and isocyanates making the product safe for our applicators, other trades, and the surrounding work site. This was a tremendous benefit as other scopes of work could take place while A&W’s crew applied the epoxy coating. The coating could be removed as a critical path activity and made concurrent with the rest of the project. This provided CLTWater with schedule reassurance and efficiency.
Rehabilitating the 60-year-old concrete involved prepping and cleaning the substrate’s surface of all debris. The surface showed depths of up to ½-inch of exposed aggregate. Afterward, we applied a single coat of approximately 125 mils of Warren’s 301-14 epoxy at a rate of five shifts per clarifier.