KMED: a two step process to remove color from pulp mill wastewater
A reaction between caustic bleach water and potassium permanganate was examined for its ability to remove colloidal color. The effectiveness of this reaction was found to depend on concentration and was not affected by pH. Under certain conditions, a large floc formed that was easily removed. The supernatant of the reaction, after being mixed with both acid wastewater and process wastewater, was treated with ozone to further reduce the residual color. The product of the two step process yielded an overall color reduction of more than 97%.