Sequential Oxidation-Bioremediation for Treatment of Chlorinated and Petroleum Chemical Releases

SEQUENTIAL OXIDATION-BIOREMEDIATION USING ACTIVATED PERSULFATE TECHNOLOGY

Introduction

Sequential Oxidation-Bioremediation (SeqOxiBio^TM) using a mixture of sodium persulfate and lime generates the sulfate radical, one of the strongest and most versatile oxidizing species that is capable of destroying many of the most recalcitrant compounds, including:

• chlorinated ethenes (TCE, PCE, DCE, and vinyl chloride);
• chlorinated ethanes (1,1,1-TCA, DCA);
• chlorinated methanes (carbon tetrachloride, chloroform);
• polyaromatic hydrocarbons (PAHs);
• phenols;
• petroleum hydrocarbons (including Naphthalene, 2-methylnaphthalene, BTEX, MTBE, and TBA), and;
• 1,4-dioxane.

In addition to being powerful oxidant, activated persulfate is, molecularly, a very stable compound, which allows it to continue to attack contamination over an extended period of time. This characteristic, in conjunction with its movement through the subsurface via natural processes such as ground water flow, gravity, and capillary attraction, results in the effective treatment area becoming far greater than that of the observed injection radius.

The 2-Stage Treatment Process

The first stage of the treatment process occurs as the activated persulfate is introduced into the contaminant plume resulting in the chemical degradation (oxidation) of the targeted pollutant. Subsequent to the chemical reaction stage, oxygen in the subsurface is depleted, creating an anaerobic condition, and the second stage of the treatment takes over. Under these circumstances, the remaining sulfates are used by the indigenous microbial population to further reduce the contaminant plume, effectively augmenting the naturally occurring attenuation process. In essence, the predominant short-term reaction is chemical oxidation, while the longer-term remediation process is biological oxidation.