Case Study: Preparing a Former Log Pond for Conversion Into an Aerated Stabilization Basin Weyerhaeuser Mill, Springfield, Oregon, 1995 Environmental Conference Proceedings

Susan T. Zeni, P.E.

Weyerhaeuser Company

Stuart A. Ryman, R.G.

EMCON

In 1993, the Weyerhaeuser Springfield, Oregon Containerboard mill increased its production rate by constructing an old corrugated container (OCC) recycling plant. The existing aerated stabilization basin (ASB) for the facility was operating at maximum capacity before the new OCC plant was brought on-line. As a result, the mill was required to add secondary treatment capacity. Weyerhaeuser determined that a second ASB should be constructed in a portion of a 14 hectare log pond. The log pond no longer was used to transport logs, however, the pond still received process and storm water discharge and supported the plant’s back-up fire water system. In order to prepare a portion of the log pond for the new ASB, Weyerhaeuser was required to assess the chemical quality of both the log pond water and sediment, evaluate wetland issues, and drain a portion of the pond and remove sediments while maintaining the process, storm water, and fire water needs. The log pond conversion project at the Weyerhaeuser Springfield mill was a success because Weyerhaeuser developed a “teaming attitude” with both the site preparation consultant and the ASB design consultant. This paper discusses both the practical and technical lessons learned during this project.