Water Conservation Strategies and Opportunities for Sustainability of Pulp and Paper Sector—An Overview of Recent Trends

Abstract

Water is an integral medium for pulp and paper making. Though the Indian Paper Industry is traditionally considered to be a water intensive industry, but actually around 90% of the water consumed is discharged as waste water implying industry is not a water guzzler actually. Today with increasing water scarcity, dwindling ground water resources, increasing environmental awareness and efforts to improve river water quality through minimization of industrial discharge into the river, introduction of new regulatory norms on fresh water consumption and wastewater discharge as well as stringent pollution norms in offing, the onus has come upon pulp and paper mills to adopt appropriate strategies and approach, state of art technologies, equipments and treatment systems to achieve the environmental compliance. In this context CPPRI has provided assistance and guidance to pulp and paper mills in water conservation/optimization of fresh water consumption and have helped several pulp and paper mills specially in river Ganga Basin and river Hindon sub-basin in reducing fresh water consumption, waste water discharge and pollution load leading to overall improvement in environmental status and sustainability. Adoption of “Bare Minimum Technologies (BMT)” including energy efficient as well as clean and green technologies like continuous digesters, improved pulp washing systems, oxygen delignification, elemental chlorine free bleaching, fiber recovery system, modifications in showers on paper machine, upgradation of existing ETP up to tertiary treatment system, adoption of chemical recovery system (for agro based mills), strategies and identification of areas for reuse and recycling of back water and treated effluent etc. as well as optimization of various key process operation variables have been key factor in reducing the water foot print of many pulp and paper mills in recent times. In addition, studies are under progress at CPPRI on evaluation of potential of membrane filtration system in reducing pollution load specially Total Dissolved Solids (TDS), Color and Lignin (a major bottleneck in reuse/recycling of treated effluent). The treated water quality achieved is suitable for reuse/recycle in various operations of pulp and paper making which can facilitate reduction in water footprint of pulp and paper mills to a greater extent. The present paper highlights a few such trends or success stories of pulp and paper sector which has helped in significant water conservation.