Management of Sludge Landfill Stability During Excessive Rainfall Conditions, 1998 Environmental Conference Proceedings

Joseph T. Kovich

Sr. Project Engineer

Boise Cascade Corporation

The Boise Cascade St. Helens pulp and paper mill for the past two years has implemented an aggressive proactive management plan for the handling of the primary clarifier sludge at it’s St. Helens, Oregon Landfill Facility. The Landfill was experiencing increasing problems with extremely “wet” primary clarifier sludge from the material at the site in the storage cells and with fresh material arriving at the site. The lack of leachate de-watering capability combined with a lack of consistent landfill management practices and “Mother Nature” working against the efforts to correct existing problems had to be addressed in a total different approach. A project team of specialists was formed to address the major concerns of the St. Helens mill. A time schedule was made for each task to be completed. The primary goals were to keep the St. Helens mill operating providing a consistent, stable primary clarifier solids disposal system, stabilizing the present landfill conditions, improve the de-watering conditions, and configure the landfill so that additional future waste could be added to the landfill. With landfill costs continuing to increase, the task was to achieve all the primary goals utilizing minimal cost investment and reduce the cost per ton of sludge entering our landfill. In addition, the majority of the work to be done had to be accomplished during one of the “wettest” periods of the year while at the same time the landfill was experiencing record high rainfall conditions over the past two years. The project team consisting of technical specialists, operations and maintenance personnel, and management was formed to address all of the key areas of concern and then implement the plan of action over the next two years. The steps taken dramatically improved the drainage capability for leachate removal at the landfill, increasing cell life at the landfill without the high cost of new cells being added at this time. In addition, the added control measures at the mill for processing the primary clarifier sludge material prior to being brought to the landfill site was now drier and more consistent making transportation and spreading at the landfill easier and more cost efficient. The new landfill management practices implemented at the landfill site have also provided continued successful operating results through all weather conditions that will benefit the St. Helens mill for the present and future years.