The filter media in three filters at Water Treatment Plant 8 were more than 30 years old. Under Globaltech’s continuing services design-build contract with Palm Beach County Water Utilities Department, we were tasked with removing the old media (anthracite, sand, and gravel) and replacing it with new.

After conducting investigations into the physical state of the media to be removed and the underdrains, Globaltech coodinated the work of a specialty contractor that sandblasted the filter’s concrete walls and applied a waterproof coating to the interior.

Once the interior coating was cured, Globaltech proceeded with the media installation. Because the filters had a fixed roof, the media could not be poured in with heavy machinery; instead, it was provided in 1-cubic-foot bags that were hand-carried to each of the filters.

Project Achievements / Benefits

• Prior to beginning the filter removal, Globaltech cored the existing media to determine if it was calcified. Results showed that the media was rounded but loose, and could be vacuumed out without additional handling.
• Once the filter media was removed, an endoscope was used to examine the filter underdrains for debris. No significant clogging was found in the underdrains. The underdrain holes of each filter were drilled out to the original specification diameter.
• During the project, only one filter was taken out of service at a time so the water treatment plant could maintain service to its customers.