“We applied epoxies and some high-build systems in our trials,” he says. “But the flexible polyurea system appeared to be the way to go as time went on. And the one that really proved itself was the flexible, high-build polyurea system.”
Steinbach began budgeting for the project that would apply the AR 425 system at 80 mils to the plant’s two primary clarifiers, two secondary clarifiers, wet well, grit tanks and aeration tanks. In order to facilitate plant operation while coatings operations were under way, Steinbach divided the project into three phases, to be completed one per year, starting in 2005.
Phases 1 and 2
Spectrum application teams addressed the 80-foot secondary clarifiers and the wet well in phase 1. The phase lasted about three months and required the presence of five application personnel on-site, according to Spectrum managing partner Jim Orr.
According to Orr and project manager Steve Wolf, the trickiest part of the phase was applying the coating in the three-foot-deep influent and effluent trough areas,which narrowed to about a foot in some areas.
“Getting in and around those areas was very challenging,” says Orr.“Our guys really had to work to get the coating applied properly at the lower levels.”
The AR 425 also allowed Spectrum to engineer a solution to another corrosion issue at the plant. Aluminum hand rails surround the clarifiers and are present throughout the plant.The rail posts, however use a steel insert to secure a connection to the concrete, and here’s where corrosion had taken its toll.
“Water was seeping in to the railing mounts, leading to degradation of the steel and the surrounding concrete,” according to Steinbach. “So we had Spectrum apply the coating system up onto the posts by about 4 inches. This effectively encapsulated the steel and is keeping water out.”
Summer 2006 saw Spectrum take on the grit tanks and primary clarifiers in phase 2.