Taking a “Do-It-Yourself” approach to save time and reduce cost was the goal maintenance crews at Miami-Dade Water and Sewer Authority (WASA) sought in order to solve their corrosive issues at South District’s wastewater clarifier. Operations personnel decided to shutdown one of their wastewater clarifiers at the South District Sewer Treatment Plant in order for the maintenance specialists to apply a new protective topcoat to their steel and concrete surfaces in order to return the structure back into its next service cycle. Protection the steel and concrete with a premium coal tar epoxy coating will add years to the integrity of the walls, troughs, floors, and steel scrapers; and therefore the coating will extend the life of the structure and also extend the maintenance cycle as well.
After shutdown, immediately the steel started flash rusting due to a lack of any sufficient barrier protection from oxidation. The presence of rust is one indication, of many, that a coating was needed.
Miami-Dade’s South District maintenance personnel selected using a Graco airless spray gun. Using a spray gun was optional, the coating selected could be rolled, however, because of the many intricate angles and bars that make up the steel sludge scrapers – it was best decided to spray rather than roll.
The Graco airless spray pump is shown here pumping Epoxytec UroShield Bitumastic, a proven coal tar bitumen-modified epoxy.
In-house maintenance crews begin spraying the steel clarifier sweepers using Epoxytec UroShield Bitumastic.
The steel sweeper structures get one coat of Epoxytec UroShield Bitumastic at 16 mils thickness.
The concrete walls and troughs get 2 coats of Epoxytec UroShield Bitumastic at 16 mils each for a total 32 mil system in order to properly fill the profile of concrete and add sufficient protection against algae build up and abrasion of the algae removal sweepers.
Miami-Dade Water and Sewer completes the coating project, and doing so all in-house, which saved the County considerable time and money. Doing the work in-house, with Epoxytec’s support and training, also provided them the beneficial know-how and understanding of the systems protecting their infrastructure.