Phosphate is commonly used to minimise corrosion to potable water distribution systems, residential, commercial, and industrial potable water piping, and reduce lead corrosion to comply with EPA standards. To achieve passivation of new or previously untreated systems phosphate is typically dosed at > 3.0 mg/L as orthophosphate.
Phosphate concentration monitoring is necessary to ensure adequate corrosion control. Manual monitoring is possible, however to avoid under- or overfeed during periods of fluctuating system flows continuous monitoring is advantageous. Controlling phosphate feed with an online instrument allows the user to minimise corrosion, meet regulatory and aesthetic requirements, and reduce chemical costs.