Decolorization Of Pulp Mill Bleaching Effluents Using Activated Carbon PDF Download

The pulp and paper industry produces large volumes of effluent containing, among other things, dark brown lignin and lignin degradation products. The exact nature of the chromophoric (colour causing) groups in the wastes and the effects of these colour bodies on the aquatic environment are not known. However, developmental work on several processes for colour reduction has reached full scale application and colour removal is now required in many local areas for various reasons. Colour reduction can be achieved by either technical changes within the mill or by effluent treatment systems. In-plant modification can range from simple, inexpensive measures such as pulp washing and better "housekeeping" practices, to complex technological changes such as implementation of oxygen bleaching. While in-plant changes should be considered and implemented as a first preference, external treatment may often still be required. There are a large number of external treatment methods which are known to be technically feasible for colour removal from pulp and paper mill effluents.