Hi there all, I have a problem in my WWTP plant. The color is very high, as well as COD. I heard that color reducer agent can remove color from water and I would like to know in which stage do I have to use the color reducer - in primary treatment or in tertiary treatment? In which ppm do I have to use it? Currently, the chemical dosage is: Lime 1000 ppm Alum 1200 ppm and poly 1 ppm Color reducer ??? ppm Kindly share you experience guys. Thanks/Regrads, Abdul Gaffar - Senior Chemist.