Evaluation of an “Off the Shelf” Automated Chemical Phosphorus Removal System

In order to reduce ferric chloride consumption and maintain effluent compliance, the wastewater plant in Beaver Dam, Wisconsin installed an ‘off the shelf’ phosphorus control system manufactured by Hach Company in Loveland, Colorado. In this installation, the phosphorus control system measures effluent orthophosphate and flow, using that information in algorithms to control ferric chloride feed in real time before the final clarifiers. After 160 days of operation, the phosphorus control system reduced the ferric chloride feed by 56% (26,688 gallons) which equates to approximately $30,691 saved in chemical costs alone. Based upon these figures, return on investment of the installed cost of the phosphorus control system was 6.8 months.