WELCOME CHEMICAL AND BIOLOGICAL TREATMENTS Chemical and Biological Treatments Chemical oxidation Chemical reduction Biological treatment Many technologies can be applied in situ or ex situ ID: 1040473
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1. DeNovo Constructors, Inc.WELCOMECHEMICAL AND BIOLOGICAL TREATMENTS
2. Chemical and Biological TreatmentsChemical oxidationChemical reductionBiological treatmentMany technologies can be applied “in situ” or “ex situ”.Certain technologies can treat soil, groundwater, or both.
3. Chemical OxidationIn situ chemical oxidation (ISCO) – involves injecting oxidants into the subsurface to react with contaminants.Oxidation-reduction reactions produce harmless substances (e.g., CO2, water, inorganic chloride).Various oxidants are available – will depend on the type of contaminant, concentrations, and subsurface geology.Oxidants used, will have different oxidation potentials (relative strength).
4. Chemical Oxidation – Common OxidantsOxidantContaminants TreatedPeroxide, Fenton’s ReagentTCA, PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1,4-dioxane, MTBE, tert-butyl alcohol, explosivesOzone (injected as gas - sparging)PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, MTBE, TBA, explosivesOzone + peroxideTCA, PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1,4-dioxane, MTBE, tert-butyl alcohol, explosivesPermanganate (potassium or sodium)PCE, TCE, DCE, VC, BTEX, PAHs, phenols, explosivesActivated Persulfate*PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1,4-dioxane, MTBE, tert-butyl alcohol, pesticides *Activation by iron, hydrogen peroxide, heat, or high pH (lime or NaOH)
5. Chemical Oxidation – Application methodsDirect push injectionFixed well injectionIn situ soil blending applicationEx situ soil blending application
6. Chemical ReductionIn Situ Chemical Reduction (ISCR)Zero-valent Iron (ZVI)ZVI + added carbon substrate – induces anaerobic reductive dechlorination by microbes.Targent contaminants are mostly chlorinated solvents (PCE, TCE, DCE, VC, TCA, carbon tetrachloride).Also can treat some pesticides and explosives.Often combined with anaerobic biological treatment.
7. Chemical Reduction – Application MEthodsInjection:Direct injectionHydraulic/pneumatic fracturingPlacement:Placement into trenches or excavationsDeep soil mixing
8. BIOLOGICAlAerobic and Anaerobic Remediation MethodsUses natural microbes in the subsurface to degrade contaminants.Stimulates microbes by adding oxygen, and/or nutrients.Biological can be combined with chemical methods (e.g., ISCO + ORC; carbon source + ZVI)
9. Aerobic Bioremediation - ORCAddition of oxygen and nutrients enhances aerobic bioremediation.Converts biodegradable contaminants into carbon dioxide and water.ORC can be applied as slurry or as a dry, solid powderApplication methods – soil mixing/blending, direct injection, recirculating wells, direct placement into excavations or barrier walls.In situ or ex situ applications.
10. AnAerobic BioremediationAddition of carbon source (e.g., lecithin, lactic acid, molasses) and nutrients (nitrogen and phosphorus) Enhances anaerobic bioremediation – enhanced reductive dechlorination.Mainly in situ applications – comes as slurry and emulsions.Direct injectionsSoil mixingPlacement into excavations
11. Specialty Suppliers and productsProvides chemicals and specialized products.Provides dosing and technical support during design.Some companies can provide onsite field support during application.Example CompaniesPeroxyChemRegenesisTersus EnvironmentalOrinISOTECMECx
12. Project example –CHEMICAL REDUCTION soil mixing @ an army ammunition planIn situ soil mixing of 7,500 cubic yards of clay soil contaminated with chemicals.Grout slurry mixture consisting of Zero valent Iron and bentonite – produced in onsite mixing plant.Overlapping soil columns mixed with deep-soil auger using a hollow Kelly bar Slurry pumped through Kelly bar to the auger/mixer equipped with injection ports.
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