Walden was retained by a local municipality to provide management and oversight services for the removal of a 10,000-gallon fiberglass underground storage tank (UST) located at an apartment complex under the jurisdiction of the municipal Housing Authority. This UST was originally used to store heating oil for the apartment complex. When the Housing Authority installed and switched to a natural gas heating system for the apartment complex, the obsolete UST was shut down and taken out of service.
Prior to the tank removal, Walden notified the local health department and state agencies regarding the work. A work plan, which included the size of the tank to be removed, the tank registration information, the contractor’s information, a soil sampling plan, and a site plan, was submitted to both agencies and were approved a week prior to the start date of the UST removal.
During the on-site activities, Walden oversaw the draining of liquid waste accumulated within the tank, excavation of the tank area, removal of the piping and fittings, removal of the tank, and the backfilling and restoration of the excavation. A representative from the local health agency was present on-site during the tank removal to verify there were no signs of a spill prior or during the removal and that there were no punctures within the tank bottom or visual/olfactory evidence of soil impacts. After the tank was removed, Walden collected samples of soil from the sidewalls and the bottom of the excavation. These endpoint soil samples were screened for Volatile Organic Compounds (VOCs) with a photoionization detector (PID) and then sent to a New York State ELAP certified lab for further analysis to determine if any soil was impacted due to the UST or the tank removal. The endpoint sampling results verified that the concentrations of VOCs in soils remaining on-site meet the applicable standards. After the excavation was backfilled, Walden retained and coordinated with a paving contractor to restore the site to the client’s satisfaction.