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In May 2018, a local contractor removed one (1) 1,000-gallon abandoned UST in Springfield, Massachusetts that formerly contained no. 2 fuel oil with oversight provided by local Fire Department personnel. The removed UST was located adjacent to the eastern side of the apartment building, installed parallel to the eastern wall of the structure. According to available information, the UST was installed circa 1934 and has not had not been used since the heating system was converted to natural gas in the late 1980s.   

As part of initial remedial response actions, WjF provided oversight during the excavation of approximately 35 cubic yards of contaminated soil from the former UST location.  Laboratory results of post-excavation soil samples indicated petroleum hydrocarbons at concentrations exceeding applicable soil standards / upper concentration limits (UCLs) at depth and adjacent to the apartment building foundation.  Thus, WjF proposed to conduct in-situ chemical oxidation (ISCO) applications using hydrogen peroxide through injection borings using a GeoProbe.

Technology Used

In-situ Chemical Oxidation (ISCO) using hydrogen peroxide

The vertical extent of soil contamination was determined to be ~15 and the depth to groundwater was determined to be at least 48 feet below surface grade, therefore, WjF respectfully requested to waive the pre-and post-application groundwater monitoring requirement associated with applying remedial additives in accordance with 310 CMR 40.0046(4), as WjF determined that monitoring wells were not necessary. MassDEP conditionally approved the ISCO program.

WjF conducted two (2) ISCO applications that consisted of injecting approximately 675 total gallons of hydrogen peroxide solution at a concentration of ~11% via ten (10) injection borings using a track mounted GeoProbe.  

During the applications, WjF vented the basement of the building by discharging the ambient air through a duct away from the building, along with periodically monitoring the basement during the application using a PID and observed for off gassing or steam. However, no PID readings above background, off gassing, or steam were observed.

WjF mixed the hydrogen peroxide solution in 55-gallon drums and applied it using low-pressure injection (10-15 psi) via a double diaphragm pump through the drill rods equipped with a retractable two-foot injection screen, using a bottom-up approach. WjF added a diluted iron solution of ferrous sulfate heptahydrate to catalyze the reaction prior to injecting. The order of the injections was staggered in order to avoid overloading the formation.  

WjF returned to the Site at a later date to collect post-remediation soil samples using a track-mounted GeoProbe in the application/injection area to evaluate the ISCO applications. WjF submitted select soil samples to a local analytical laboratory for VPH/EPH analysis in accordance with MassDEP Methodologies. The laboratory results indicate that the soil has been successfully remediated, allowing for regulatory closure.

EPH Fraction concentrations before and after H2O2 treatment (in mg/kg), with % reduction:

Sample ID C9-C18 Aliphatics C19-C36 Aliphatics C11-C22 Aromatics
N West (before) 26,600 5,580 13,200
N West (after) 475 206 510
% reduction 98 96 96
S West (before) 19,800 9,070 20,100
S West (after) 2,400 420 2,100
% reduction 88 95 90
North (before) 10,300 <4,080 <4,080
NA (after) <10.3 <10.3 <10.3
% reduction 100 100 100


The results of soil analyses indicated that the ISCO activities conducted was effective in reducing the risk of harm posed by the fuel oil release to the environment of the Site, thereby achieving regulatory closure.