Soil Treatment and Remediation at N.W. Pipe and Casing Superfund Site

The Northwest Pipe and Casing/Hall Process Company Superfund Site is located in Clackamas, Oregon. Soil and groundwater were contaminated by former pipe manufacturing and coating facilities. The primary contaminants include polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from spent solvents, primers, coal tar, coating product containers, coal tar residues and oils.

The main objective of the project was to remove the most severely contaminated soils for off-site treatment or disposal. Excavation and disposal of over 20,000 tons of hazardous waste was completed, and an additional 10,000 tons of contaminated, non-hazardous soil was excavated, treated off-site via low temperature thermal desorption, and then returned to the site and placed as a thin cap over excavated areas. Other work included clearing and grubbing, developing an extensive network of on-site haul roads, abandoning and protecting existing monitoring wells, demolition of concrete structures and underground utilities, the construction and operation of an on-site VOC soil treatment cell, collection and disposal of NAPL and contaminated groundwater, and removal and disposal of USTs, piping and a variety of drummed wastes. An extensive erosion control system was custom designed to protect wetlands on the site, managed an air quality monitoring program, and prepared associated regulatory documentation and reports.

Project Performance

The wide variety of contaminants and complexity of this project emphasized the crucial role that site organization and management plays in minimizing costs. Successful management of the complexity of excavating, stockpiling, segregating and treating the varied waste streams allowed the project to complete on time and under budget.