3815_PGSF WMVD Pkg 2_Vol 4-2_03.03.2026_BXWA_Certified

ASPECT CONSULTING 6 FINAL PROJECT NO. AS190583A-08  MAY 21, 2025 between 1979 and 1981 and was then used to store wood chips for use in pulp and paper operations. Scott Paper Company continued pulp and paper operations at the Upland Area through 1995 when it merged with K-C. The distribution warehouse located on the south end of the Upland Area was originally constructed by 1959, and a southwestern extension was constructed in the 1970s. In 1974, the mill constructed a sulfite recovery boiler (Boiler No. 10) to recover spent liquor from operations and to combust it for steam generation and the conversion of sulfur dioxide, which was reused in the process. In 1995, five “Dutch Oven” wood-fired boilers were replaced with a new boiler (Boiler No. 14), which is owned by the Snohomish County Public Utility District (PUD). Also in 1995, the Snohomish County PUD built the biomass fuel shipping pier and related conveyors, which were used by the K-C mill as well. Figure 2-2 depicts primary historical features of the pulp and paper mill. 2.2.3.1 Mill Demolition and Placement of Crushed Material The mill operations were permanently ceased in April 2012. Demolition of the K-C mill started in summer 2012 and was completed in July 2013. Demolition of the mill structures involved generation of a very large quantity of concrete and brick demolition debris (estimated 120,000 cubic yards), which was crushed on site. The crushed material (CM) was then graded across approximately 32 acres of the Upland Area where the mill pavement had been removed. The pavement was not removed within and north of the secondary wastewater treatment area on the north end of the Upland Area (now the City’s Utility Property). Additional CM has been documented to have been placed in the southwest corner of the site. This CM was not visible on the surface of the ground because it was covered up with soil. The extent of the placed CM is depicted on Figure 2-4. Temporary erosion and sediment control best management practices were conducted throughout mill demolition in accordance with a Construction Stormwater General Permit and corresponding Stormwater Pollution Prevention Plan (David Evans and Associates, 2012). The complete removal of the CM from the Site in 2020 is described in Section 4.5. 2.2.3.2 Pulp and Paper Mill Wastewater Management Until 1951, wastewater from the K-C mill, consisting of concentrated spent sulfite liquor (SSL), waste bleach water, and pulp fiber wash water, was discharged untreated to the East Waterway through up to seven outfalls located adjacent to the facility (outfall locations are show in Exhibit A of the Agreed Order). In 1951, the mill constructed a deep water outfall (Outfall SW001), in conjunction with the Weyerhaeuser mill located south of the K-C mill. The Outfall SW001 discharged concentrated SSL from the K-C mill and Weyerhaeuser Mill A westward to the deep waters of Port Gardner Bay. In 1963, the mill’s sanitary effluent was separated from its process effluents and routed to the City of Everett’s sanitary sewer system. The wastewater treatment facility, with two primary clarifiers and an interceptor sewer system, was constructed by Scott Paper Company in 1964. In July 1965, the mill put into operation waste sedimentation facilities with two primary clarifiers and an interceptor sewer system. An industrial wastewater treatment plant was constructed at the mill in 1979 and put online in January 1980. The