ABSTRACT
This chapter provides an overview on the design and operation of chemical phosphorus removal facilities. Waste pickle liquor is added to the primary clarifier influent for phosphorus removal. The chapter reviews the specific process options and discusses the rationale used to select the option appropriate for a given application. It discusses the aluminum salt option. Alum addition consumes wastewater alkalinity. Three specific metal salt dose points are commonly used in wastewater treatment plants: primary clarifiers, secondary clarifiers, and to tertiary treatment systems consisting of chemical clarifiers and/or filters. The chapter suggests that metal salt addition is the most commonly used chemical phosphorus removal process. The factors that influence chemical selection are: cost, alkalinity consumption, quantities of sludge generated and safety. The chapter evaluates use of alum or ferric chloride for phosphorus removal. It presents the pumps used in chemical phosphorus removal. Pump casing and impeller materials must be suitable for the liquid to be pumped.
