High-Performance Coating for A 200,000 Gallon BoltedSteel Alum Sludge Storage Tank

The existing 200,000-gallon bolted-steel floc storage tank has been in service since March 2009 as part of a surface water treatment system where alum is used to treat water from an adjacent canal for nutrient removal. The generated floc is collected in a deep pond and is periodically removed by dredging and pumped into the open-top 200,000-gallon floc storage tank. The stored alum floc contains elevated levels of H2S which create a corrosive environment with pH levels from 4.5-6.5. The floc is circulated using an internal floating mixer which subjects the tank walls to mild to moderate scour potential. Small areas of rust have been observed on an increasingly frequent basis in recent years. Interior portions of the tank have been recoated with the original epoxy-type coating. The exterior of the tank has the original installed coating. Tank dimensions: Width - 42 ft; Height - 20 feet.

Division 02 -	Existing Conditions, Subsurface Investigation.
Division 03 -	Concrete, Concrete Reinforcing, Cast-in-Place Concrete.
Division 05 -	Metals, Structural Metal Framing, Metal Decking.
Division 23 -	Heating, Ventilating, and Air Conditioning (HVAC), Facility Fuel Piping, Facility Fuel-Storage Tanks.
Division 31 -	Earthwork, Clearing and Grubbing, Grading.
Division 32 -	Exterior Improvements, Fences and Gates.
Division 33 -	Utilities, Storm Drainage Utilities.