Services: Drilling | Categories: Secant & Tangent Walls | Location: New York Metro

Con Edison E. 115th Street

East 115th St, NY

Con Edison

Contract Value:

Project Dates:
2016 to 2017

  • Excavation and disposal of contaminated material
  • Drilling of concrete secant pile wall at various depths
  • Installation of large diameter PVC wells
  • Landscaping, site improvements and site restoration


This project for ConEdison entailed the installation of a NAPL migration barrier wall and large PVC wells in close proximity to the Manhattan School of Science and Mathematics. The purpose of the installation was to excavate and dispose of contaminated material and then contain the potential migration of further contaminants along the FDR Drive and under the school with a combination concrete/recovery well secant pile wall. Posillico also performed site restoration through landscaping and other improvements to complete the project.


This project was complex for many reasons. The secant wall had to be driven to different heights depending on the level of the confining layer at different locations. It also required specialty equipment to drill large diameters within tight spaces. Site controls presented a challenge as well in terms of dust, smell, noise, and safety. Work took place on active school grounds, including shared walkways with students and at times near the FDR Drive. It needed to be completed within the active school schedule and involved odorous materials which could impact the comfort of the surrounding community.


To handle the challenge and nuisance of disturbances, Posillico took a very pro-active approach in tackling each issue. The crew used odor suppressant foam constantly, to minimize odors. The noisiest sections of work were performed outside school hours. The ground was constantly sprayed with water to keep the dust down. A security team was brought on to protect the site perimeter and keep pedestrians safely off the remediation site. Posillico used signage and barriers along the FDR to protect its employees from active traffic. Modeling the site in AutoCAD prior to project kick-off allowed the team to plan for the right equipment and led to Posillico completing the project safely and on schedule.