Vegetative Closure of a Pulp and Paper Sludge Landfill, 1993 Environmental Conference Proceedings

Closure of pulp and paper sludge landfills is often problematic due to the saturated, weak and compressible nature of the waste materials they contain. Regulatory agency closure requirement typically include a soil cap that is constructed at an adequate slope to maintain drainage. However, often the waste will not even support the load of low-ground-pressure construction equipment required to place such a cap. In addition, to accommodate the significant total and differential settlements that occur, large quantities of fill are needed to meet the slope requirements.

This is the situation encountered at the Weyerhaeuser Company pulp and paper sludge landfill in Everett, Washington. To meet the challenges imposed at the site, closure method was designed, which incorporates a vegetative closure and a network of dikes. As the dikes settle, paths for surface and subsurface drainage of the sludge are created. The sludge is stabilized by this dewatering process which allows access onto the dikes and into the basin for seeding and fertilizing the sludge.