The daily flow rate from multi-media filtration is nine million gallons. Each carbon contactor has a capacity of .9 MGD. The carbon adsorption system consists of a total of 17 contactors, each containing 43 tons of granular activated carbon, operating at a hydraulic loading rate of 5.8 gpm/ft2. Contact time is 30 minutes.

The carbon contactors operate in parallel and are designed to operate either upflow or downflow (they are currently operated in the upflow mode). The purpose of the GAC is to adsorb various dissolved organic compounds from the treated water. Typically, the carbon removes up to 70 percent of total organic carbon. As the system is operated, the adsorptive capacity of the carbon is eventually exhausted and must be regenerated at regular intervals.

A furnace is located in the carbon building to reactivate spent carbon. The furnace has a regeneration capacity of 12,000 pounds per day. Approximately 93 percent of the carbon is recovered during each regeneration cycle. When regeneration takes place, the spent carbon is taken from the bottom of the columns in slurry form and sent via two-inch hoses to the carbon regeneration tanks. In the upflow mode the bottom half of the carbon is that which becomes exhausted. Operating the contactors in upflow mode allows the regeneration of the bottom half of the contactor's carbon, which is also the portion that is easier to remove.