The City of Dunedin’s greensand filter media removal and replacement project involved removal and replacement of filter media in five existing pressure filter vessels at the City’s Reverse Osmosis Water Treatment Facility. The pressure filter vessels provide iron and manganese removal prior to the plant’s reverse osmosis membranes.
The project consisted of removing and replacing the existing filter media (anthracite, greensand, silica sand, and gravel) in four existing 30,000 gallon steel tanks and installing new media in a fifth pressure vessel that had been cleaned by the City. Vogel Bros. was also responsible for re-painting the inside of each tank, as-needed repairs to the exterior coating, installing new air release valves and replacing damaged air laterals. Media was removed from the existing vessels using a vacuum truck, placed in dumpsters for dewatering, and disposed of off-site. Because the existing pressure vessels are completely enclosed, the replacement media had to be placed and compacted by hand inside each tank. To maintain plant operations, the work was sequenced so that no more than two of the five filters were out of service at any given time.