Sludge Dewatering Process Optimization/Cost Reduction at an Integrated Pulp and Paper Mill, 1998 Environmental Conference Proceedings

Abitibi-Consolidated Inc. operates a sludge &watering facility at their pulp and paper mill in Kenora, Ontario, Canada. This facility combines and dewaters de-ink, primary and secondary sludge which is then landfilled. The control and operation of the sludge dewatering process has evolved to produce substantial cost reductions through dewatering chemistry improvements, process control modifications, ‘key’ measurement development and detailed reporting. On-site representation along with corporate support from the chemical vendor is combined with the process control and material handling expertise of the customer (ACI) to accomplish process improvement and cost reduction. Since the start up of the facility in August 1995 chemical cost reductions of over 65% have been realized by focusing on areas such as sludge blend ratios and consistencies, equipment modifications and control optimization, and optimization of the chemical addition points. Looking to the future, further improvements are targeted in the areas of performance variability dampening, gravity thickener belt cleaning, high efficiency polymer/sludge mixing, pressate total suspended solids monitoring and make-down water temperature optimization. This paper will present information describing the key steps involved in achieving the reduction of costs while overall dewatered sludge production increased by 33%.