The sludge transfer chemical feed system at the Southport Advanced Wastewater Treatment Plant serving metro Indianapolis, Ind., needed an overhaul. Three 4,000-gallon fiberglass-reinforced plastic closed-vessel tanks inside the building stored ferrous chloride, which is pumped into the sludge being conveyed from Southport to the city’s Belmont plant to control odors caused by hydrogen sulfide. By June 2010, the 9-foot-diameter, 12-foot tall chemical storage tanks had significantly exceeded their design life and had developed small cracks that allowed the corrosive chemical to leak out. In addition, small spills from tank filling had corroded the concrete floors beneath and walkways around the tanks. Two chemical metering pumps and various other metal HVAC, plumbing and electrical equipment were also badly corroded and needed replacement.