Recent Developments and Synergies in the Use of Oxygen for the Biological Treatment of Waste Waters from the Pulp and Paper Industry, 1996 Environmental Conference Proceedings

Traditionally, air has been used widely in the biological treatment of pulp and paper effluents In order to face more stringent regulations and increasing pollution loads, pure oxygen appears today as a strong alternative. In this paper, focus is given on the following various elements that make a pure oxygen solution attractive and competitive versus air : Compactness Cost competitiveness because new technologies for on-site oxygen production have drastically reduced the delivery costs, especially when oxygen or ozone is already used in the mill. State of the art of pure oxygen injection in aeration tanks is detailed, emphasis being given to new Ventoxal type diffusers. Two major applications are reviewed: Pure oxygen upgrade of existing treatment plant : Airoxal process New plant especially designed for O2 use : Aspal processes. Finally, case studies from DEGREMONT and AIR LIQUIDE reference lists highlighting upgraded and pure oxygen plants are presented.