Client:  Former Gasoline Retailer

Project: Underground  Storage Tank Closure

Location:  New Jersey

 

Description:  The owner of two former gasoline retail stations hired EWMA when they were interested in removing the underground storage tank (UST) systems from two properties located on opposite sides of a highway.  There were five USTs on one property and nine USTs on the other property.  The USTs ranged in size from 2,000-gallons to 10,000-gallons and contained either gasoline or diesel fuel.  Prior to removing the tank systems, EWMA completed the required 30-day notification.  
 
During the removal of the tanks at the first property, EWMA’s certified subsurface evaluator noted odors and elevated photoionization detector (PID) readings in the area of the tanks, piping runs, and pump islands.  Consequently, a considerable amount of petroleum contaminated soil was excavated and post-excavation soil samples were collected.  The results of the sampling identified elevated levels of benzene and total xylenes in one sample location, which required further soil excavation to ensure all of the contaminated soil was removed.  Upon completion of all excavation activities at the first property, approximately 1,100 tons of contaminated soil were disposed of at a licensed disposal facility. 
 
Removal of the tanks at the second property was a more complex matter.  Originally, it was thought that six tanks were located on the property.  When EWMA began excavating the six tanks, soil contamination was noted between them.  EWMA began removing the source area of contamination, and during the excavation of contaminated soil three additional USTs were encountered that needed to be removed to properly close all of the tanks at the property.  At the end of the tank closure process at the second property, a total of 3,900 tons of petroleum contaminated soil was excavated and disposed of at a licensed disposal facility.

Tank decommissioning and removal activities of all tank systems on both properties was completed within two weeks.  Minor benzene, toluene, ethylbenzene, and xylene (BTEX) ground water impacts at one of the properties have been addressed via monitored natural attenuation.  At the other property, a sizable methyl tertiary butyl ether (MTBE) plume is currently being remediated via dual-phase soil vapor extraction/air sparging (SVE/AS) soil and  a ground water treatment system.