SHATTUCK CHEMICAL SUPERFUND SITE CHALLENGES OF A3/4-Acre MOVABLE CONTAINMENT STRUCTURE AND CHANGING REMEDIAL ACTION OBJECTIVES

摘要

This case study describes technical and operational challenges encountered and solutions developed during implementation of the“second”remedy at the Shattuck Chemical Superfund Site,in accordance with the Amended Record of Decision.The off-site remedy requires “mining”of cement-stabilized“monolith”material from the previous remedy,and excavation of soil above the Remedial Action Objectives. rnThe remedy is complicated by significant involvement of stakeholders,including the City of Denver,members of the public,and elected officials,who expressed significant concerns about dust generation.As a direct result,it was determined that the remedy would be conducted under a project structure to contain dust.A“movable”3/4-acre structure was selected in lieu of a 5.5- acre structure.Technical and operational challenges of working with the project structure include:1)moving a structure across a trapezoidal-shaped property;2)meeting Uniform Building Code wind and snow loads in a high wind area and the use of ground anchors to tie down the structure;3)erection of a building on wheels;4)moving the structure across varying terrain,keeping the structure level as it moves across the remedied areas and controlling the move speed;5)maintaining indoor air quality;6)maintaining worker safety;and 7)maintaining public safety. rnThe remedy is further complicated by changing Remedial Action Objectives.The Amended Record of Decision changed(lowered)the Remedial Action Objectives for two radionuclides of concern.Compliance must be demonstrated in two locations,both of which had been remedied to the previous,less stringent standards:1)a 20 ft perimeter strip of property surrounding the Site between the monolith and the property line;and 2)up to 8 ft of vadose zone soil below the monolith.