Louis J. Burkhardt, Raytheon, 528 Boston Post Road, MS 1880, Sudbury, MA 01776; Tel:978-440-1855, Fax: 978-440-1800, Email: louis_j_burkhardt@raytheon.com
Ronald Slager, Raytheon, 528 Boston Post Road, MS 1880, Sudbury, MA 01776, Tel: 978-440-1862, Fax: 978-440-1800, Email: ronald_c_slager@raytheon.com
Michael R. Ravella, ERM, 399 Boylston St., 6^th Floor, Boston, MA 02116, Tel: 617-646-7808, Fax: 617-267-6447, Email: mike.ravella@erm.com
Rick Lewis, ERM, 399 Boylston St., 6th Floor, Boston, MA 02116, Tel: 617-646-7815, Fax: 617-267-6447, Email: rick.lewis@erm.com

One or more historical releases of 1,1,1-trichloroethane (TCA) and trichloroethene (TCE) occurred at a site underlain by heterogeneous glaciolacustrine sand and silt deposits. Hydraulic conductivities range from 5.5x10^-5 cm/s to 1.6x10^-3 cm/s.  The vertical distribution of hydraulic conductivity, evaluated using a combination of cone penetrometer and Waterloo Profiler borings, indicates a layered system, consisting of silt over sand over silt. A series of remedial pilot studies were conducted, including air sparging and soil vapor extraction (AS/SVE), in situ chemical oxidation (ISCO) using permanganate, and in situ biological reductive dechlorination (BRD) using sodium lactate. Results of these pilot studies indicated that heterogeneous geologic conditions limited the efficacy of AS/SVE. ISCO was effective at treating TCE within the pilot area, but had little effect on TCA. A BRD pilot study indicated that this technology was effective at treating both TCA and TCE. Based on results of the BRD pilot study, a full-scale BRD recirculation system has been designed and installed, and will begin operation in 2006.

Influence of Heterogeneity on Effectiveness of ISCO Treatment: Step 1

James Ewart, N.A. Water Systems, Airside Business Park, 250 Airside Drive, Moon Township, PA 15108, Tel: 814-809-6719, Fax: 814-809-6711, Email: james.ewart@veoliawater.com
Philip T. Harte, U.S. Geological Survey, NH/VT Water Science Center, 361 Commerce Way, Pembroke, NH 03275, Tel: 603-226-7813, Fax: 603-226-7894, Email: ptharte@usgs.gov
Richard Goehlert, U.S. Environmental Protection Agency, Region 1, 1 Congress St., Suite 1100, Boston, MA 02114-2023, Email: Goehlert.Dick@epa.gov
Thomas Andrews, N.H. Department Of Environmental Services, 29 Hazen Drive, Concord, NH 03301, Email: t_andrews@des.state.nh.us

Insitu chemical oxidation (ISCO) treatment can effectively destroy chlorinated solvents, such as tetracholoroethylene (PCE). Treatment effectiveness depends on the distributions of nonaqueous and aqueous-phase masses, stratigraphy, groundwater velocity, geochemistry, and adequate reaction time.

ISCO treatment was initiated in September 2003 at the Operable Unit 1 (OU1) of the Savage Superfund site in Milford, NH. The site has a large (0.5 mi²) volatile organic compound (VOC; primarily PCE) plume. Remediation of OU1 began in 1998 by installing a slurry wall through glaciofluvial deposits surrounding suspected source areas. Among these sources is a former drain and pit area, now targeted by a test well field (INEEL well field). The ISCO treatment injected 8,500 pounds of permanganate in an active flow scheme using two injection and two extraction wells in the INEEL well field. The ISCO test was tracked for reactants and reaction byproducts for over 1 year. 

Estimated amounts of PCE destroyed ranged from 5 to 300 times preinjection aqueous-phase concentrations, indicating that the bulk of the oxidized VOCs were in nonaqueous phases prior to the injection. The higher rates were in areas of low preinjection concentrations, indicating that nonaqueous VOCs were probably more susceptible to oxidation than those in areas of greater concentration. Permanganate persisted more than 1 year in selected areas, which helped suppress aqueous phase concentrations of VOCs. 

A primary factor affecting the persistence of permanganate was convective mass transport. Extraction well pumping induced transport along a northeasterly sloping basal stratigraphic contact between a permeable coarse sand layer and a less permeable basal till layer. This contact had the highest initial dissolved VOC concentrations suggesting a likely DNAPL source. Although, the DNAPL position is affected by the contrasts in vertical permeability between the coarse sand and basal till, the permanganate transport is affected by the lateral transport in the coarse sand layer.

Surfactant Enhanced In Situ Chemical Oxidation

Daniel W. Felten, P.E., LSP, LEP, Environmental Compliance Services, Inc., 588 Silver Street, Agawam MA 01001, Tel: 413-789-3530, Fax: 413-789-2776, Email: dfelten@ecsconsult.com
Frederick W. Hostrop, Environmental Compliance Services, Inc., 607 North Main Street, Suite 11, Wakefield MA 01880, Tel: 781-246-8897, Fax: 781-246-8950, Email: fhostrop@ecsconsult.com
Stephen LaRoche, Vice President, The Westford Chemical Corporation®/BioSolve® Group, P.O. Box 798, Westford, MA 01886, Tel: 800-225-3909, Fax: 978-667-8773, Email: slaroche@biosolve.com

In situ chemical oxidation (ISCO) has been used for decades for the remediation of residual dissolved phase contamination, however, does not address adsorbed or non-aqueous phase (NAPL) source area which exists at many sites.  Specialized surfactants have become increasingly popular for enhanced recovery of petroleum and chlorinated hydrocarbons.  Successful, cost-effective application of ISCO requires solubilization of the contaminants, as ISCO takes place in the aqueous phase.  The application of specialized surfactants can significantly enhance ISCO by solubilizing and increasing the bioavailability of adsorbed phase NAPL to allow the ISCO (and residual bioremediation) processes to proceed with optimal effectiveness.  Several case studies will be presented which demonstrate how remediation costs and timeframes can be significantly reduced using surfactants and in situ chemical oxidation.  The interaction of geology, contaminant fate and transport, surfactant and ISCO chemistry, and economics will be discussed. 

Principles and Practices with a Novel Chemical Oxidation System: RegenOx™

Robert Kelley, Regenesis, 4813 Hyacinth Court, Plainfield, IL  60544, Tel: 815-230-3516, Fax: 815-230-3517, Email: bkelley@regenesis.com

RegenOx™ is a proprietary (patent-applied-for) in situ chemical oxidation process using a solid oxidant complex (sodium percarbonate/catalytic formulation) and an activator complex (a composition of ferrous salt embedded in a micro-scale catalyst gel).  With its highly active catalytic system, RegenOx is capable of treating a broad range of soil and groundwater contaminants including both petroleum hydrocarbons and chlorinated solvents. RegenOx uses a basic oxidizer complex and thus generates alkaline conditions (high pH) and does not rely on operating under the acidic conditions (low pH) that are required when using standard catalyzed hydrogen peroxide (Fenton’s chemistry).  RegenOx is safe and easy to apply to the contaminated subsurface without the health and safety concerns and lingering environmental issues that have become associated with other chemical oxidation technologies. RegenOx has been applied at over 50 sites for both chlorinated and petroleum-based contaminants.  Several successful applications are now complete. 

The case studies to be presented are from sites exhibiting varying lithologies, using different application methods (such as direct push injection, in-situ and ex-situ soil mixing) and within different regulatory environments.  Treatment results from sites containing a variety of contaminants will be presented, including a site with a mixed chlorinated solvent and petroleum hydrocarbon plume.  Initial contaminant concentrations ranged from 20-80 mg/L for the primary contaminants of concern.  After the first injection round, BTEX concentrations decreased by 50-66% and chlorinated solvents decreased by 63-90%.  The presentation will include a discussion on evaluating the principles of design, practical lessons learned, and life-cycle costs for chemical oxidation with RegenOx.  The discussion will also evaluate various methods available to perform on-site feasibility tests and bench tests which can be utilized to evaluate the potential effectiveness of in-situ chemical oxidation.

Case Studies:  Gasoline and Fuel Oil Remediation Using Biologically Enhanced Chemical Oxidation

Lawrence H. Lessard, PG, LSP, LEP, Lessard Environmental, Inc., 30B Cherry Hill Drive, Danvers, MA 01923, Tel: 978-777-2300, Fax: 978-777-4355, Email: llessard@lessard-environmental.com
Christopher D. Glod, PG, LSP, Lessard Environmental, Inc., 1920 Mineral Spring Avenue, Suite 9/10, North Providence, RI, 02904, Tel: 401-353-7066, Fax: 401-353-7067, Email: cglod@lessard-environmental.com
Melanie A. Head, Ph.D., Lessard Environmental, Inc., 30B Cherry Hill Drive, Danvers, MA 01923, Tel: 978-777-2300, Fax: 978-777-4355, Email: mhead@lessard-environmental.com

Chemical oxidation is transitioning from an innovative technology to a common remediation technique for cleanup of hydrocarbon impacted soils and groundwater. Concerns regarding the implementation of chemical oxidation include safety during application and disruption of natural contaminant attenuation. These concerns stem from the exothermic nature of the oxidation process and sterilizing effects of the oxidants on soil microorganisms. The extent of contamination can, in theory, increase substantially in the absence of natural attenuation. Close examination of the oxidation reactions has brought about modifications that increase safety and dramatically stimulate aerobic microbial activity resulting in integrated chemical oxidation and bioremediation and subsequent enhanced natural attenuation.

Lessard Environmental, Inc. has developed a process called Biologically Enhanced Chemical Oxidation (BECO, US Patent 6,923,596) which integrates chemical oxidation and bioremediation as a concurrent and co-located process. Implementation of BECO is both temporally flexible and spatially scaleable.  The process integrates the oxidation and bioremediation by increasing subsurface temperature, available oxygen and nutrients and by modifying contaminant distribution during remedial additive applications. 

Case studies demonstrating the effectiveness of BECO will be presented for gasoline and fuel oil treatment.  Remediation progresses as an integrated couplet of remedial additive applications and biological activity.  The stimulated microbial activity reduces the total quantity of oxidant and number of applications required for remediation with oxidant alone. Heterotrophic plate counts during the remediation projects typically increased from baseline concentrations of 10² to 10³ CFU/mL to concentrations of 10⁵ to 10⁷ CFU/mL following BECO application events.

Biologically Enhanced Chemical Oxidation transitions to natural attenuation seamlessly. The close integration of the chemical oxidation and biological action precludes field efforts to establish the proportionate effects of each process separately.   The presented case studies will demonstrate the effectiveness of BECO in reducing fuel oil and gasoline associated hydrocarbons in full scale applications. 

ISCO with Ozone - A Primer on Basic Requirements

Joseph Mendez, Piper Environmental Group, Inc. 11600 California Street Castroville, CA 95012, Tel: 831-632-2700, Fax: 831-632-2701, Email: joem@peg-inc.com

The presentation addresses basic requirements for the design, safety and operation of ozone systems used in in-situ chemical oxidation remediation projects. It is intended for persons that are in the early stages of learning about ozone as an ISCO agent. The essay provides information on ozone generators, oxygen generators, air filters, dryers and compressors, ambient and process monitoring equipment, gas distribution, ozone pressure boosting, methods of injection, sizing, materials of construction, safety and maintenance. It also presents some general cost guidelines for these systems.

The presentation provides information on two major topics: the generation of ozone and in-situ ozone treatment systems.

Ozone generation

This section offers information on ozone generation, systems and safety. First, it addresses different components of an ozone system and discusses them in detail. Secondly, it reviews basic safety and regulatory requirements for the installation and operation of ozone generators.

In-situ ozone treatment

This section provides information on the design and sizing of in-situ ozone treatment systems. In particular, this section discusses air vs. oxygen as feedstock gas, water vs. air-cooling, ozone gas distribution, materials of construction, air and ozone mixing, ozone gas pressure boosting, ozone gas monitoring equipment, dissolved ozone vs. ORP, sparging methods, pitfalls to watch and cost guidelines.

Comparison of Several Advanced Oxidation Processes for Reactive Dyes Photodegradation

Igor Peternel, BSc., University of Zagreb, Faculty of Chemical Engineering and Technology, Department of Polymer Engineering and Organic Chemical Technology, Marulićev trg 19, HR-10000 Zagreb, Croatia, Tel: +385 1 4597 124, Fax: +385 1 4597 143, Email: peternel@fkit.hr
Sanja Papic, PhD, University of Zagreb, Faculty of Chemical Engineering and Technology, Department of Polymer Engineering and Organic Chemical Technology, Marulićev trg 19, HR-10000 Zagreb, Croatia, Tel: +385 1 4597 124, Fax: +385 1 4597 143, Email: spapic@fkit.hr
Natalija Koprivanac, PhD, University of Zagreb, Faculty of Chemical Engineering and Technology, Department of Polymer Engineering and Organic Chemical Technology, Marulićev trg 19, HR-10000 Zagreb, Croatia, Tel: +385 1 4597 124, Fax: +385 1 4597 143, Email: nkopri@fkit.hr

Chemical treatment such as Advanced Oxidation Processes (AOPs) seem to be very useful for treating wastewaters containing organic dyes [1,2]. AOPs are defined as the processes that involve highly reactive species, particularly hydroxyl radicals in sufficient quantities to oxidize the majority of complex organic chemicals in the water effluents [3]. Hydroxyl radicals are the most important oxidants due to their high reactivity and unselectively towards organic compounds. UV based AOPs as well as photocatalysis systems such as combination of a semiconductor (TiO₂, ZnO, etc.) with UV irradiation, are widely used to decompose organic pollutants in industrial wastewater and groundwater[4]. Solid particles, synthetic zeolites (HY, NH₄ZSM5) used in this study are micro porous crystalline materials with well-defined structures and with strong ability to act as catalysts for chemical reactions which take place within the internal cavities The aim of this study was to investigate application of UV/H₂O₂/O₃, UV/Fenton and UV/TiO₂ processes for the degradation and mineralization of reactive azo dye C.I. Reactive Red 45. The primary objective was to determine the optimal condition for each process. Influence of zeolites (HY, NH₄ZSM5) on the process efficiency was also investigated.

Total process efficiency was estimated on the basis of total organic carbon (TOC) and spectrophotometric (UV/VIS) measurements. Partial mineralization extents obtained after a one-hour treatment followed the increasing order: UV/TiO₂ < UV/H₂O₂/O₃ <UV/Fenton while complete mineralization was obtained by . UV/H₂O₂/O₃ and UV/Fenton processes.

References

[1] M.Neamtu, A.Yediler, I.Siminiceanu, M.Macoveanu, A.Kettrup, Dyes and Pigm.(2004)
[2] N.Koprivanac, H.Kusic, D.Vujevic, I.Peternel, B.R.Locke, J. Hazard. Mater.(2005)
[3] R.Gogate, B.Pandit, Advan. Environ. Res. (2004)
[4] F. J. Beltran, J. M Encinar,. J. F. Gonzalez, Water Res.(1997)

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