Former Papermill and Landfill Superfund Site
PCB contaminated soil and landfill site remediation to construct geotechnically stable slopes for a geosynthetic soil cap to be placed over the waste.
The original papermill was constructed in the 1890’s. The former landfill site is approximately 71 acres. Paper residuals were deposited throughout the site. PCB’s were first manufactured in 1929 and continued until they were banned in 1979. Non-carbon paper once contained PCB’s. When the non-carbon paper came back to the papermills for recycling, the PCB’s found their way into the effluent from the mills. Contaminated paper residuals were then placed in the landfill. The residuals were pumped from the papermill to the landfill and deposited in various lagoons. Although over time the residuals dewater somewhat, they remain high in moisture. This moisture precludes them from being able to bear load.
The primary purpose of the project is to consolidate wastes from around the site and pull the limits of said waste back from the creek. The goal is to construct a landfill that possesses geotechnically stable slopes whereby a geosynthetic and soil cap can be placed over the waste.
Site restoration construction will include:
• Removal of all steel sheet piling along creek
• Restoration of a meandering stream bed for creek
• Creek bank enhancements and in stream riffles
• Restoration of a wetland alongside creek
During the early stages of the project, it became known that the moisture content of the paper residuals was very high. Even mixing the paper residuals with granular soil would not yield a product that could meet the strength requirements to construct the slopes of the landfill. Taplin proposed the use of a pugmill in order to amend the paper residuals with a dry, cementitious powder. Paper residuals delivered to the pugmill location would be loaded into the pugmill mixing chamber, through a hydraulic grizzly screen, utilizing an excavator. Silos containing the dry, cementitious powder convey their content into the mixing chamber. Within the mixing chamber, twin mixers combine the wet paper residuals with the dry powder to manufacture a structurally competent material. Prior to the amendment process the off-road dump trucks could not traverse the paper residuals mixed with granular soils without leaving 2’ deep ruts. Once the amendment process was introduced, the trucks could traverse over the paper residuals with minimal indentation.
In addition to the pugmill, Taplin purchased an Allu mixer to stabilize the paper residuals in situ. The goal was to utilize both the pugmill and the Allu to increase production and reduce project schedule. Although field testing operations produced a product that was suitable for placement, the process was not initiated. The Allu, combined with the GPS technology on the excavator, is able to distribute a prescribed amount of amendment to a given area in order to be as precise as possible in delivery.