Treatment of contaminated water, timbers, and soils was investigated using catalyzed hydrogen peroxide, a procedure based on Fenton’s reagent [hydrogen peroxide and iron (II)]. The process produces hydroxyl radicals which oxidize essentially all organic contaminants. Fenton’s methodology was used to treat total petroleum hydrocarbons (TPH) in an oil-water separator effluent from the WSDOT White Pass maintenance station. Results indicated that the presence of surfactants affected treatment efficiency. Although surfactants lowered the effectiveness of the process, 25% of the TPH was removed.
Wood posts contaminated with pentachlorophenol (PCP) and creosote were treated using the catalyzed peroxide process, resulting in 84% degradation of PCP and 74% degradation of creosote with 6% hydrogen peroxide and 56 mg/l Fe. Estimated chemical cost for treatment was $1.00/kg of wood.
A central composite rotatable design was used to investigate the interactions between hydrogen peroxide concentration, slurry volume, initial contaminant concentration, and soil organic carbon content in the catalyzed hydrogen peroxide remediation of diesel-contaminated soil to develop design criteria for soil remediation. Two separate experimental matrices were investigated: 1) high slurry volumes and low peroxide concentration, and 2) low slurry volumes with high peroxide concentrations. Time required for high volume/low concentration system to proceed to completion was approximately three weeks; low volume/high concentration reactions were complete within three days.
The results showed that soil organic carbon content was an insignificant variable in the catalyzed peroxide treatment of diesel-contaminated soils. However, significant interactions were found for the remaining three variables. Data were analyzed for total petroleum hydrocarbon (TPH) degradation and treatment stoichiometry. Although both systems could achieve equal levels of treatment, stoichiometry of the high volume/low concentration system was significantly more efficient; therefore, high volume/low concentration was the most economical system for the remediation of diesel-contaminated soils.