Additional Services


Residual permanganate analysis can be useful for determining the amount of permanganate remaining in a groundwater sample following in situ treatment with RemOx® S ISCO reagent or RemOx® L ISCO reagent.

Due to the characteristic purple color, permanganate can visually be seen with the naked eye to about 1 part per million (PPM). For a quantitative method of analysis, a colorimeter is commonly utilized to analyze for residual permanganate. Colorimeters are user-friendly and offer a quick analysis with real-time data. Colorimeters use standard spectrophotometric methods and measure permanganate at the absorbance of 520 nanometers. Carus Remediation Technologies offers HACH DR-890 and DR-900 colorimeters as a service to our customers during monitoring at sites using one of our products. Colorimeters are rented at no cost for the first two months. After the first two months, a monthly rental fee would apply. The customers would be responsible for covering the shipping costs to and from the site location. A detailed procedure is included with the colorimeter. There is a limited amount of units available so please contact us if you would like to inquire about availability or to reserve one for your upcoming project.


Permanganate reacts with naturally occurring reduced materials in the subsurface, termed natural oxidant demand (NOD). NOD can be one of the biggest unknowns at a site and must be considered for every in situ chemical oxidation (ISCO) project. The most common way to estimate the NOD is a laboratory test procedure for determining the mass of permanganate consumed per mass dry soil after a prescribed period of time. Carus performs permanganate natural oxidant demand (PNOD) analysis following a method developed by the American Society of Testing and Materials (ASTM). A brief summary of ASTM Method D7262-10 (2016), Test Method A, for PNOD analysis follows:

For each soil sample, soil is baked at 105°C. The soils are dosed in triplicate at one initial potassium permanganate (KMnO4) concentration of 100 ml of 20 g/L KMnO4 to 50 g of soil for an initial dose of 40 g KMnO4/kg dry soil. The reactor vials are gently inverted. Following 48 hours of reaction time, the liquid portion of the treated sample is analyzed for permanganate residual following method 4500-KMnO4 Potassium Permanganate in Standard Methods for the Examination of Water and Wastewater. To order a complete copy of the ASTM method, visit

If you are interested in submitting soil samples to our laboratory for PNOD testing, the cost is nominal and the standard turnaround time is 10 business days. Soil submittal procedures can be found here and the chain of custody record here. The movement (shipping) of soil across the United States and from foreign nations is regulated by the United States Department of Agriculture. For information on whether the site soil is considered regulated or to submit soil for PNOD testing, contact a member of CRT. Access the USDA map here, or view our PNOD frequently asked questions, here.


RemOx® S ISCO reagent is supplied as a dark purple crystal or granule. Prior to injection into the subsurface, RemOx S is typically dissolved in water. In Europe, Carus offers rental equipment to assist in transferring and dissolving RemOx S into solution.


The RemOx S Reagent Dissolution System (RDS) was developed for reagent supplied in supersacks to dissolve the solid RemOx S crystals into water creating the solution for injection in a safe, efficient, and reliable way (Europe only). For more information, contact Carus.