Increased Solids and Phosphorus Removal Following Regulatory Tertiary System Upgrade at the Walton N.Y. Wastewater Treatment Plant

The Walton Wastewater Treatment Plant, located in Walton, New York, discharges into the primary tributary for the Cannonsville Reservoir, part of the NYC water supply system. Federal regulations require a drinking water filtration plant for the NYC water supply unless specific filtration avoidance requirements could be met. One of these requirements was that WWTP's discharging in the NYC watershed be upgraded to tertiary treatment. The WWTP was upgraded to include a two stage tertiary sand filtration system designed to eliminate the discharge of pathogenic protozoans while also reducing solids and phosphorus concentrations. Over six years of operation has proved the system to be robust, reliable and capable of meeting design expectations. Following installation of the system in January 2003, significant reductions in effluent turbidity (99.99%), total suspended solids (99.95%), phosphorus (99.98%) and fecal Coliform (99.99%) were realized with a 30% increase in residuals production primarily attributable to increased solids removal.