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Sigma assesses environmental issues at American Tissue

Confidential Client

AmericanTissue-IMG01Sigma provided a broad range of environmental services at the former American Tissue Mill property, a manufacturing site of tissue and freesheet paper products located a 13-acre peninsula on Lake Mohawksin in Tomahawk. The project was one of the first of its kind in the state of Wisconsin, and was completed to wide acclaim. The Wisconsin Department of Natural Resources (WDNR) has highlighted this site on their website of Voluntary Cleanup and the Voluntary Party Liability Exemption (VPLE) success stories.

Investigation

Sigma performed various Phase 1 and Phase 2 site assessments, including monitoring, sampling and surveying. Sigma coordinated wetland delineation and site surveying activities, helped establish an Environmental TIF District through the City of Tomahawk, wrote asbestos abatement and site demolition specifications and completed additional site investigation activities. Sigma also developed a Remedial Action Plan in cooperation with the WDNR VPLE program to address dioxin/furan, Polychlorinated Biphenyl (PCB) compounds, and petroleum hydrocarbon contamination at the site.

Remediation

AmericanTissue-IMG02Sigma designed the remediation strategy for dioxin/furan- and PCB-impacted soils within and around delineated wetland areas (approximately 225 feet long by up to 90 feet wide), including the acquisition of permits from the WDNR and Army Corps of Engineers (ACOE). In 2006, over 4,150 tons of contaminated soils were excavated and hauled off- site for disposal at a local licensed landfill.

The previously delineated wetland within the remediation project area was restored as required by the WDNR and ACOE — over 550 tons of peat was placed within the wetland area to match the original grades and to create hydric soil conditions to support a wetland environment. A series of coir fiber logs were installed along the shoreline of the restored wetland area to attenuate wave energy form Lake Mohawksin and allow vegetation, which consisted of over 1,000 sedge/fresh wet meadow rootstock plugs and sedge / fresh wet meadow seed mix, to populate the wetland area. Remediated upland areas surrounding the wetland were backfilled with locally-derived bank run sand to mimic the geologic conditions that existed before remediation. Sigma completed post-remediation groundwater sampling in late 2006 and the WDNR VPLE program issued final case closure and a Certificate of Completion in August 2007.