Bio-physico-chemical treatment for removal of colour from pulp and paper mill effluents

Combination of biological and physico-chemical treatment method is adopted for colour removal of paper mill effluents. On treatment of effluent with Trichoderma sp in batch studies, 72% colour reduction was achieved within 24 h. In continuous mode, treating effluent with the same fungus in a fluidized bed reactor, around 27% colour reduction was achieved. This biologically treated effluent is further treated with a poly-electrolyte (potash alum) to improve the colour reduction. Maximum colour reduction of 81% was obtained by this combined treatment.