The CP tests were performed with the same sample; 1000 mL of effluent were added in each of the 12 vats of the jar test equipment; a medium speed of 50 rpm was applied, and stirring was performed for 1 h. In each vat, 2.0–24.0 mL NaOH(12 M) were measured in order to determine the influence of pH on the precipitation of metals in the form of hydroxides. After stirring, the system was allowed to rest for sedimentation of the sludge occur and samples of the supernatant (clarifiedliquid) and the sludge formed in each vat were collected.