Alum process residues (APR) are used to remove colored contaminants from waste waters. In addition, in accordance with the invention, up to 0.1% by weight of alum and up to 5 ppm of a polyelectrolyte polymer is added to improve color removal, turbidity removal and the settling rate. The resultant APR-alum-polymer mixture together with contaminants in the waste water settles rapidly, reducing the costs of the color removal process.

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