Formatted Title

ISCO Application for the Treatment of MCB, BTEX and CF in Groundwater at a Pharmaceutical Site

Background/Objectives

Activated Klozur® persulfate creates a multi-radical attack providing greater oxidation power capable of treating common and the most recalcitrant compounds alike. Klozur® persulfates include both sodium (SP) and potassium (KP) products.  Both dissolve to provide the persulfate anion, which is typically stable for weeks to months.  Sodium persulfate is highly soluble and available to react at the time of application, whereas the low solubility of potassium persulfate has been observed to provide extended release of the persulfate anion over months to years.  This allows immediate distribution in the subsurface with the stability providing a greater radius of influence and allowing more time to make contact and degrade a wide variety of contaminants in soil and groundwater, including chlorinated solvents, petroleum hydrocarbons, and PAHs. Klozur® CR, a blend of Klozur® SP (sodium persulfate) and PermeOx® Ultra (extended-release calcium peroxide), coupled with Klozur® KP has been selected as the best long-lasting treatment solution for the contaminants of this site by providing immediate treatment with the Klozur® SP and extended treatment with both the PermeOx® Ultra and Klozur® KP.

Approach/Activities

Klozur technology has been successfully applied at several sites in Italy within the past few years. This presentation will discuss the broader program using specific sites as case studies.  One of these specific sites was at a densely populated urban area site in northern Italy. The site was characterized by historical contamination of various toxic compounds. The site, a dismantled former pharmaceutical facility, was impacted by the storage of hydrocarbons and chlorinates solvents which have resulted in groundwater contamination, including benzene (~ 1000 µg/L), monochlorobenzene (~ 250000 µg/L), chloroform (~ 54000 µg/L) and light TPHs (~ 16000 µg/L).  In 2022, a successful pilot was implemented injecting a total of 5600 kg of Klozur CR along with 1700 kg of Klozur KP in a 25% aqueous solution. In 2023, full scale remediation has been completed applying approximately 29 MT of Klozur CR and 9 MT of Klozur KP in a 25% aqueous solution.

Results/Lessons Learned

The combined remedy of ISCO followed by bioremediation has proven successful in treating petroleum hydrocarbon and chlorinated solvent contamination.  With regard to the northern Italy site, following 12 months after the full-scale application, the concentrations of contaminants had reached and maintained concentrations below the remediation goals in all monitoring piezometers in the treatment area. In particular, TPHs were reduced by greater than 85 percent, while MCB was reduced by greater than 95 percent. Monitoring data confirmed sustained elevation of oxidation-reduction potential (ORP) and dissolved oxygen (DO) as necessary subsurface conditions to support treatment.