Inherently-formed iron-based water treatment residuals (WTRs) were tested as alternative sorbents for phosphate (P) removal from contaminated process effluent from a potato processing plant. The WTRs were characterized, and their sorption efficiency and sorption capacity were tested using one- and two-stage treatment methodologies. The WTRs were capable of removing >98% of P from the effluent water. It was found that two-stage methodology improved the sorption efficiency significantly, reaching 90% removal level at less than half the one-stage sorbent dosage. WTRs are safe and economical sorbents for industrial waste water treatment, and constitute an example of industrial symbiosis, where a waste product from one industry is used to remediate the waste stream of another neighboring industry.