CleanER™ environmental remediation solutions
Zero valent iron (ZVI) is often injected in the subsurface through three common methods:
- Direct injection: Typically a direct push technology (DPT) or fixed injection point to address the treatment zone. CleanER-SI.5, CleanER-SI.10 or CleanER-SI.45 are used.
- Hydraulic Fracturing: Liquid is used to create a network of fractures with preferential flow paths. CleanER-SI.100, CleanER-SB.200 or CleanER-SR.2 are used for this application.
- Pneumatic fracturing: Gas is used to create a network of fractures with preferential flow paths. CleanER-SI.100, CleanER-SB.200 or CleanER-SR.2 are used for this application.
Soil blending with ZVI is a highly effective method for treatment of large areas of contamination or to restrict the contaminant plume migration.
Permeable reactive barriers
Permeable reactive barriers (PRBs) have been used for nearly three decades to intercept and treat contaminated groundwater. PRBs are ideal for sites with low groundwater velocities and well-defined conceptual site models (CSMs). There are many methods to install PRBs including: backhoe trenching, biopolymer trenching, continuous trenching and injection techniques. PRBs are designed to provide sufficient contact time and years of operation. Typical ZVI used for this application include CleanER-SR.2 and all other CleanER ZVI depending on the application.
Chlorinated volatile organic compound (CVOCs) remediation
In-situ chemical reduction (ISCR)
Chlorinated volatile organic compounds (CVOCs) are a primary concern for soil and groundwater remediation sites around the world. Höganäs CleanER ZVI is ideal for the remediation of chlorinated ethenes, methanes, ethanes, propanes, and other halogenated compounds. ZVI remediation also promotes a mix of both biotic and abiotic remediaition to stimulate complete contaminant.
- Chlorinated ethenes: Tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethene (cDCE), trans-dichloroethene (tDCE), vinyl chloride (VC)
- Chlorinated ethanes: Tetrachloroethene (1,1,2,2-TeCA), trichloroethane (1,1,2 or 1,1,1 -TCA) and dichloroethane (1,1 or 1,2 DCA)
- Chlorinated methanes: Carbon Tetrachloride (CT) and trichloromethane (CF)
- Halogenated compounds: Dichloro-diphenyl-trichloroethane (DDT), N- nitrosodimethylamine (NDMA), dibromochloropropane (DBCP), lindane, CFCs and 1,2-dibromoethane (EDB)
Beta-elimination vs hydrogenolysis
CleanER ZVI was designed to maximize β-elimination and limit the production of harmful daughter products from hydrogenolysis. Hydrogenolysis is the sequential replacement of chloride ions with hydrogen, thus forming compounds like cis-DCE and VC. VC and cis-DCE are more toxic and can be rate-limiting during degradation. In β-elimination, two chlorine atoms are replaced with a triple bond between the carbons, forming an acetylene group. Chlorinated acetylenes can then undergo quick degradation with ZVI to form harmless ethene or ethane. All Höganäs ZVI products were designed and selected to minimize the formation of toxic by-products.
Höganäs CleanER media is the only ZVI available with the reducing potential to treat the recalcitrant compound selenate (SeO42-). Once underground, our iron creates and maintains very low ORP conditions while providing buffering capacity to maintain neutral pH. The high surface area and material totally devoid of oil or grease promotes higher electron fluxes and slower surface passivation. All these factors lead to CleanER media having a high affinity for the adsorption of heavy metals and metalloids.
Not all ZVI media is created equal. Depend on Höganäs; portfolio of CleanER ZVI media to deliver the performance needed for your most demanding metals remediation projects.
Stabilization is key for long-term sequestration and treatment of metals. CleanER ZVI has a high affinity for adsorption, mineral complexation, and precipitation. Metal reduction is often the first step, but stabilization is vital for complete site remediation. CleanER media has a high resistance to shifts in ORP and pH which can prevent future releases of contaminants. CleanER media also has high iron content and very low contamination due to the specialized manufacturing process. As a result, the media does not leach unwanted contaminants to the site. The exceptional reactivity and efficacy of CleanER media bolsters in-situ remediation projects for the greatest likelihood of success.