UV Chambers, College Station Utilities- protective coating of concrete

College Station Utilities, Waste Water Treatmant Plant

College Station, TX, USA
Coating concrete with high performance, protective epoxy modified liner
January 2010
The final step before treated wastewater can be released back to the environment is disinfection. College Station’s wastewater is disinfected with ultraviolet (UV) light. Not only is UV light safe, it also disrupts the genetic material of disease-causing organisms, preventing the organisms from reproducing and spreading disease. The lights are installed, wall-to-wall, in two sections of a chamber that the water flows through so that no water can pass without being treated.
The chambers are formed from concrete and must be coated in order to prevent corrosion and spalling from the UV lights and waste water that passes through. The previous coating on these chambers had been almost completely deteriorated and needed to be removed entirely so that a new coating could be applied. After water blasting the surface using a 5000 psi pressure washer with a turbo nozzle, the substrate was cleaned, dried and ready for the coating of Epoxytec Uroflex.
Before the lining system gets installed. The utilization of the Epoxytec B2 Primer was applied to prevent excessive off-gassing of the concrete and to reduce the risk of pin holing.

Epoxytec Uroflex, a urethane-modified-epoxy that has a high gloss finish, was chosen for this application because of its superior protection against ultraviolet light and it’s tolerance for high levels of moisture without failing.

In the pictures above, some of the larger spalled areas of concrete were coated over with Epoxytec CPP Gel. This is an epoxy-based gel that is a 1:1 mix used for filling, patching and re-build that also helps combat corrosion.

Epoxytec’s certified applicator did a great job with surface preparation and application of Epoxytec Uroflex by using the equipment, knowledge and expertise for doing the job right way. The application of Epoxytec Uroflex started on the walls of the chambers and was done in two passes of 25 mils each to meet the specified requirements of 50 mils.

Epoxytec Uroflex can be applied in a variety of ways. For this application the use of paint brushes and rollers was utilized for an “easy-to apply” method, however; this coating can be spray applied as well.

 
Once the first coat was applied to the walls, the certified applicator dealt with some out-gassing of the concrete as shown in the pictures below. To combat this gassing, Epoxytec CPP Gel was used to coat over the areas of concern and seal the “bug holes” from out-gassing anymore. Once complete, the second coat of Epoxytec Uroflex was applied to the walls.
Once the walls were coated, the work on the floor began. The floors were swept over to ensure there were no contaminants and then Epoxytec Uroflex was applied. The floor was coated in one pass at 50 mils.
When finished, the Epoxytec Uroflex has a gloss shine which helps protect from algae build-up and UV Light damage. Once the product cures, the next day, the UV Lights can be installed and the chamber can be put back in service.

This was the crew’s first application with Epoxytec Uroflex and they finished the coating of this chamber in three days from beginning to end. Once this chamber was put back into service, they started on the next chamber. The certified applicator finished the second chamber, from surface preparation to finished product, in one day and put back into service the next.

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