F. Wayne Hill Membrane Filtration Project

About the Program

Category: County Resiliency (Best in Category)

Year: 2022

The F. Wayne Hill Water Resources Center is Gwinnett County’s largest and most advanced wastewater treatment facility. With a permitted capacity of 60 million gallons per day, this facility uses complex physical, biological, and chemical treatment processes to treat domestic and industrial wastewaters. While the facility has consistently treated the water to the highest standard, one process presented significant operational challenges – the membrane filtration process. This process, designed to remove particles as small as 0.04 microns (almost 2,000 times smaller than the width of a human hair), is subject to reduced performance when contaminants accumulate on and within the membranes, commonly referenced as “membrane fouling.” The purpose of this project was to optimize the membrane filtration process to reduce fouling and restore the performance of the membrane filtration process. Based on the findings of this multi-year effort, Gwinnett County changed its pretreatment additive from an iron-based chemical to an aluminum-based chemical. This change reduced the fouling potential of the feed water, as well as the operating pressures and chemical costs for the membrane filtration process. In addition, the performance of five membrane trains severely fouled with iron was restored with an oxalic acid cleaning solution that further reduced the operating pressures. Together, these actions reduced Gwinnett County’s operating costs by more than $450,000 per year and allowed Gwinnett County to realize more than $800,000 in savings in the 22 months since conversion.