The latest trends in the paper industry are towards manufacturing by a neutral or alkaline process, greater consumption of secondary fibers and the closing up of the process water systems. Paper machine systems usually support significant growth of micro-organisms due to congenial and favorable conditions persisting during the manufacture of paper.

Most of the Indian pulp and paper industry bleaches the pulp by conventional bleaching sequence (CEHH). The final discharge of the mill contributes to high COD load and AOX which is highly toxic in nature.