Discharge from a textile plant in Monroeville, Ala., paid 90 percent of operating costs for the Hudson Branch Wastewater Treatment Plant. The 2 mgd (design) activated sludge extended aeration facility ran two 125 hp propeller-type aerators in its 11-foot-deep wastewater pond. Power usage averaged $12,500 per month.
When the textile plant closed in 2009, Hudson Branch installed a baffle curtain in the pond, cutting its capacity in half. With flows averaging 250,000 gpd, operators cycled the active aerator on and off. Although running it 10 hours per day lowered utilities to $4,000 per month, it was too expensive to run for
