Studies on colour removal from bleach plant effluent of a kraft pulp mill

A comparative study for colour removal of pulp bleach plant effluent with three different decolorising agents: fly ash, high molecular weight amine (Kemamine T 1902D) and lime, showed 90% or more colour removal. Fly ash treatment offered a promising way for colour removal (94%); amine treatment yielded better colour removal than fly ash but had comparatively high cost. The large amount of lime needed to remove the colour beyond 90% restricts its use, since large‐scale equipment would be costly.