The Carus name is synonymous with permanganate. Carus was one of the early leaders in the development of in situ chemical oxidation using permanganate and was instrumental in developing the remediation market overall. Permanganate is typically the "go-to" product for chlorinated solvent treatment, but can also be used to treat other contaminants of concern such as: 1,4-dioxane, polyaromatic hydrocarbons, phenolic compounds, and energetics. Carus manufactures remediation-grade RemOx® S ISCO reagent (potassium permanganate) and RemOx® L ISCO reagent (40% sodium permanganate), our two pioneer products, as well as dilute permanganate product offerings.
Our diluted bulk deliveries of RemOx S and RemOx L are supplied directly to remediation sites, eliminating the need for large volumes of dilution water or equipment on site. CRT has partnered with several regional chemical manufacturers to provide local dilution and delivery of different concentrations of our remediation grade permanganates to our customers. We can deliver RemOx® S-D ISCO reagent as a 1%, 2%, or 3% potassium permanganate solution and provide RemOx® L-D ISCO reagent as a 5%, 10%, 15%, or 20% sodium permanganate solution.
Permanganate does not require activation and is applicable over a wide pH range. Research has shown that permanganate does not sterilize the microbial community in the treatment area. While permanganate is present, the microbes may be depressed. However, once the permanganate has been consumed, the microbial populations have been shown to flourish due to the release of organic carbons from the soil matrix. Permanganate is frequently used in treatment-train approaches with a focused permanganate injection scheme in the source area followed by injection of CAP 18® or CAP 18 ME® anaerobic bioremediation products downgradient for treatment of the dissolved plume.
Persulfate SR ISCO reagent and RemOx® SR+ ISCO reagent, two novel sustained-release remedial technologies, are the first true ISCO products that can be used in barrier approaches to mitigate offsite contaminant migration. The presence of a protective wax barrier slows down and controls oxidant release, enhancing the efficiency of ISCO and allowing for long-term passive treatment of organic contaminants in reactive barriers and zones.
Conceptual Model of Sustained-Release Oxidant Reactive Barriers/Zones
SR can be formed as cylinders for direct push applications, inserted into holders for emplacement into permanent or temporary wells. The material may also be chipped/cubed for hydro-fracturing into low permeability media for treating back diffusion of organic contaminants. SR has been applied at over 30 sites worldwide and offers an excellent treatment option for barrier applications as well as treatment of residual source zones.
Persulfate SR ISCO reagent can be used for treatment of petroleum hydrocarbons as well as other contaminants of concern. Persulfate SR can be used for barrier applications as well as treatment of residual source zones. RemOx® SR+ ISCO reagent is a combination of RemOx S and sodium persulfate in a paraffin wax matrix. This product can be used to degrade a variety of contaminants including chlorinated ethenes, chlorinated ethanes, chlorinated methanes, benzene, toluene, ethylbenzene, and xylene, methyl tertiary butyl ether, polyaromatic hydrocarbons, petroleum hydrocarbons, 1,4-dioxane and pesticides.
Vadose zone treatment can be challenging for ISCO. Most of the commonly used oxidants for in situ treatment require groundwater advection and diffusion to distribute the oxidant through the subsurface. In situ blending is commonly used to help address this issue.
Photo courtesy of Redox Tech, LLC
Photo courtesy of Redox Tech, LLC