The North Lee County Water Treatment Plant (WTP), located in Fort Myers, Florida, treats brackish groundwater from the Floridan aquifer using Reverse Osmosis (RO) followed by degasification and disinfection. After beginning operation in October 2006, the WTP faced several challenges that resulted in the inability to meet the 5 million gallon per day (mgd) nameplate permeate capacity, including problems with irreversible membrane fouling due to strontium sulfate (SrSO4). A potential strategy to minimize sulfate-based scaling is to eliminate sulfuric acid addition to the RO feed water. As part of a recent rehabilitation and expansion project at the WTP, a pilot study was conducted to evaluate the efficacy of eliminating sulfuric acid addition to the RO feed water, as well as to compare the ability of three different scale inhibitors to minimize membrane fouling. This article presents the results of pilot testing and discusses the operational and economic benefits associated with conversion of the WTP to acid-free operation.
Nyfennegger, J. and T. Seacord. "Acid Elimination Study for the North Lee County RO Water Treatment Plant." AMTA Solutions, Winter 2013, pp.1-7.