A LOOK AT REGULAR GRADE GASOLINE REACTED WITH HYDROGEN PEROXIDE IN A LABORATORY SETTING – WHAT'S LEFT AFTER THE BTEX IS GONE

The release of petroleum hydrocarbons to the subsurface environment is a problem that property owners, governments and responsible parties have been battling since tanks have been buried underground. Traditional remediation techniques such as pump-and-treat systems and dig-and-haul are used to address a significant number of subsurface spills; however, other, less traditional techniques have also been employed to affect site remediation. Chemical oxidation of petroleum hydrocarbons via hydrogen peroxide has been used as an environmental remediation technique with varying degrees of success. Some successful case studies have reported regulated gasoline constituents were lowered below target cleanup levels, while other case studies report no reduction of regulated gasoline constituents or that the concentrations rebounded over time. Little information is available regarding the in-situ chemistry of the reaction between petroleum hydrocarbons and hydrogen peroxide. As a result, a series of laboratory experiments was designed to study the effects of chemical oxidation in the presence and absence of a soil medium. The study focused on 1) the oxidation of a benzene, toluene, ethylbenzene and total xylene (BTEX) standard to determine if chemical derivatives were produced and 2) the oxidation of a sample of regular grade gasoline to determine what order the gasoline constituents were oxidized over time. The study was limited to headspace analyses and monitored the degradation of gasoline constituents over a period ranging from 12 hours to 12 days. The results indicate that the volatile BTEX constituents oxidize early in the process but a host of gasoline constituents can remain after the BTEX concentrations fall below method detection limits.