Anaerobic digestion offers a unique treatment option for the dairy industry. Not only does anaerobic digestion reduce the COD of an effluent, but little microbial biomass is produced.

This article discusses some of the techniques for handling sludge including: sludge thickening, sludge conditioning, sludge dewatering, sludge digestion and sludge storage.

Orient Paper Mills, Amlai is an old integrated pulp and paper mill. There is a continuous effort to reduce water consumption per ton of paper produced. The plant is a pioneer in effectively using the treated effluent for its own plantation through HRTS and do not discharge any coloured effluent in the river.

Total water and environment management in a paper mill is the need of the hour to ensure that the dual needs of lower water consumption as well as eliminating waste discharge are met. This is made possible by having an holistic approach to the problem rather than looking at end of pipe solutions like recycling the total waste water produced etc.

Black liquor management for small and medium mills based on agri-residues is still a problem, though several technologies are developed. One of the non conventional technologies being practiced by many of the mills is Modified Copeland Process.