Aggressive Remediation of NAPL and Coal Tar Impacted Sites Using Ozone and Hydrogen Peroxide Injection
Charles Whisman, Groundwater & Environmental Services, Inc., Exton, PA

The Use of Permanganate at Two Chlorinated Ethene Sites

Michael F. Dacey,  GeoInsight, Inc., 25 Sundial Ave. Suite 515 West, Manchester, NH 03103, USA, Tel: 603-314-0820, Fax: 603-314-0821, Email: mfdacey@geoinc.com

Single and multiple in-situ applications of sodium and potassium permanganate were completed at two sites in Massachusetts and New Hampshire and monitored for short- and long-term impacts to chlorinated ethene concentrations in ground water.  Concentrations of the primary constituents, tetrachloroethene and trichloroethene, were observed to be significantly reduced in target monitoring wells, but post-injection response times varied from one week to over one year.  Injection result variability is attributed to various factors including injection quantity/volume, number of injections, rate of injection, and geology/hydrogeology of the receiving formation.

Permanganate reacts almost instantaneously to cleave the carbon-carbon double bond in chlorinated ethene compounds.  However, matrix heterogeneities result in preferential permanganate loading in higher permeability zones.  Post-injection permanganate distribution to lower permeability zones is accomplished primarily by diffusion and advection and results in longer time frames to treat some target areas.  Significant post-injection rebound occurred at one site that was attributed to re-equilibration between the treated dissolved phase and the adsorbed phase.  In this case, multiple targeted applications were successful in treating both the dissolved- and adsorbed contaminant phases, and resulted in long-term (permanent?) dissolved-phase contaminant concentration reductions.  Treatment in the overburden smear zone was effected by low water table position at the time of treatment with residual rebound attributed to permanganate depletion prior to achieving complete contact with the full smear zone thickness.

To avoid displacement of source area contaminants, applications were refined to use a minimum volume of permanganate and carrier liquid.  Minimally diluted sodium permanganate was injected at very low rates and solid potassium permanganate granules were placed within a smear zone trench.  In both instances contaminant displacement and downgradient migration was minimized by using focused applications of concentrated permanganate.

Based upon the results from these two sites, multiple smaller permanganate applications over a longer time frame are recommended to better evaluate the full effect of each application and enable more targeted follow-up applications.  This approach potentially reduces chemical costs, but should be weighed against labor costs and other time related factors.

A “Green Oxidant” for In-Situ Chemical Oxidation for the Treatment of Contaminated Soils

Maureen Dooley, Regenesis, 19 Belmont Rd, Wakefield, MA 01880, USA, Tel: 781-245-1320, Email:  mdooley@regenesis.com
Ben Mork Ph. D., Regenesis, 1011 Calle Sombra, San Clemente, CA 92673, USA, Tel: 949-366-8000, Email: mork@regenesis.com

A variety of oxidants have been used to degrade organic contaminants in industrial wastes, soil and groundwater, including percarbonate, perborate, peracetic acid, nitric acid, persulfate, permanganate, and ozone.  Sodium percarbonate (SPC) is often cited as a powerful, but safe, environmental benign (“green”) oxidant for these applications. In fact, SPC has been used in numerous industrial and household products (e.g. detergent bleaches) since the 1960’s replacing oxidants like perborate because SPC has less environmental concerns.  However, proper activation of SPC is important to its efficiency, especially in in-situ applications for the purpose of transforming groundwater or soil contaminants into less harmful chemical species. Catalyzed SPC systems, like RegenOx™, have been shown to be very effective in oxidizing a wide range of contaminants.  This ISCO technology exhibits many “green” attributes which make it more environmentally friendly when compared to other oxidants.  The details of these attributes will be the topic of this presentation.

Micro-Encapsulated Oxidant Technology: Enhancing In Situ Chemical Oxidation (ISCO) with Selective Oxidation and Controlled-Release Permanganate

Pamela J. Dugan, Ph.D., Beth Vlastnik, Sheryl Ivy, Carus Corporation, 315 5th Street Peru, IL  61354, Tel: 815-224-6870, Fax: 815-224-6896
Lindsay Swearingen, Jason Swearingen, Specialty Earth Sciences, New Albany, IN

Controlled-release techniques have been utilized extensively in diverse fields such as pharmaceutical and agrochemical technologies. However, controlled-release of an oxidant during in situ chemical oxidation (ISCO) is an emerging concept that is extremely relevant to the field of environmental remediation, yet to-date has received little attention. ISCO with permanganate, persulfate, and catalyzed hydrogen peroxide has shown great promise for remediation of many recalcitrant organic contaminants of concern (COC). Because the oxidant also reacts with natural organic matter, inorganic soil constituents, and other reduced compounds, having a protective barrier that controls the release of the oxidant, and provides a coating that has an affinity for, and dissolves rapidly in hydrocarbons, may enhance the efficiency of ISCO.

Micro-encapsulated potassium permanganate particles (MEPPs) were created and characterized. Paraffin wax is used as the environmentally benign matrix material for encapsulating the sub-micron size solid permanganate particles. The paraffin matrix not only serves to protect the solid potassium permanganate particles from fast dissolution and potentially undesirable nonproductive reactions but allows for selective release of permanganate in the presence of dense nonaqueous phase liquids (DNAPL). The paraffin wax met the following requirements: solid at room temperature, substantially water-insoluble (i.e., hydrophobic), soluble in tetrachloroethene (PCE) DNAPL (i.e., oleophilic), biodegradable, and resistant to permanganate oxidation. To evaluate selective and enhanced-release of permanganate in the presence of DNAPL, batch tests were conducted in zero headspace reactors (ZHRs). The goal of these experiments was to evaluate the rate at which MEPPs were released in deionized (DI) water and in the presence of PCE DNAPL.  Results indicate accelerated permanganate release from MEPP's in the presence of DNAPL as compared to permanganate release in the MEPP reactors containing DI water. Experimental results reveal that the encapsulated oxidant technology holds promise enhancing traditional ISCO through the creation of controlled-release micro-encapsulated permanganate capable of selective-release in the presence of DNAPL. Future work involves investigation into encapsulating other oxidants, and catalysts.

Aggressive Remediation of NAPL and Coal Tar Impacted Sites Using Ozone and Hydrogen Peroxide Injection 

Charles Whisman, P.E, Vice President of Engineering, Groundwater & Environmental Services, Inc., 440 Creamery Way, Suite 500, Exton, PA 19341 Tel: 610-458-1077, Ext. 3008, Fax: 610-458-2300, Email: cwhisman@gesonline.com

This presentation will discuss innovative ways to aggressively remediate sites with large NAPL plumes, including diesel fuel, heating oil, and coal tar impacts.  Case studies will discuss how ozone and hydrogen peroxide injection systems can reduce volatile organic compound composition (in NAPL, soil, and groundwater) as well as the NAPL/coal tar thickness and volume.  The presentation will discuss recent case studies where ozone and hydrogen peroxide injection systems were designed and operated to achieve cleanup goals at sites with NAPL impacts.   

This discussion will evaluate tools that can assist with the evaluation and design of the chemical oxidation system, including laser induced fluorescence, enhanced feasibility testing, and the membrane interface probe.  Case studies include information obtained from remediating significant NAPL impact at manufactured gas plant (MGP) facilities, Brownfield sites, heating oil releases, and petroleum refineries/terminals.  These case studies are completed in-field projects which utilized chemical oxidation for an expedition and aggressive remediation of significant NAPL mass.  The discussion will provide guidance regarding the type of NAPL that may be suitable for chemical oxidation and considerations for safely implementing a NAPL remediation strategy. Case studies will provide a detailed analysis of the remediation effects on soil, groundwater, and NAPL during aggressive chemical oxidation, and evaluate the various investigation and confirmatory tools were used to assess the remediation performance.

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