Hoboken Block 110 Remediation
2013 to 2015
- Steel Sheet Piling
- Earth Retention Systems
- Transportation and Disposal of Contaminated Soils
This environmental remediation project entailed the mass removal of MGP contaminated soil. The project included the installation of a steel sheet pile hydraulic barrier wall around the site perimeter, construction of a frozen soil support of excavation wall and erection of a negative pressure enclosure to prevent the offsite emission of VOCs. Work also consisted of site dewatering, excavation, disposal of +/- 100,000 tons of impacted hazardous and non-hazardous soil to a depth of 28 ft. below grade, as well as the relocation of the negative pressure enclosure using a crane.
WHAT MADE THIS JOB COMPLEX
Work took place in a dense urban area with compromised public utilities adjacent to the site. The work scope required the excavation of soil to a depth of 24 ft. below the water table, making dewatering a crucial component of the project and calling for innovative and expert solutions. In addition, the presence of volatile contaminants presented a serious issue for treatment, for the community and for the construction team, requiring the development and integration of stringent protocols.
HOW POSILLICO SOLVED IT
To address City restrictions and reduce the Support of Excavation required, Posillico implemented innovative “Ground Freezing” technology, eliminating the need for internal bracing or tiebacks. The frozen soil wall also enhanced ground water cutoff by sealing the interface with bedrock, facilitating dewatering. Due to concerns for the emission of VOCs, a tent was used to create covered excavation areas and odor control foam was sprayed on open excavation areas. The health and safety concerns of working in a closed excavation were addressed by Posillico’s Health and Safety Team with overarching success. By carefully selecting the enclosure, and coordinating several tent-moves, Posillico completed the excavation and backfill of the entire site successfully and with minimal impact to the community.