DENOVO CONSTRUCTORS INC WELCOME CHEMICAL AND BIOLOGICAL TREATMENTS

DENOVO CONSTRUCTORS, INC. 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”. • Certain technologies can treat soil, groundwater, or both. 2

CHEMICAL OXIDATION • In situ chemical oxidation (ISCO) – involves injecting oxidants into the subsurface to react with contaminants. • Oxidation-reduction reactions produce harmless substances (e. g. , CO 2, 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). 3

CHEMICAL OXIDATION – COMMON OXIDANTS Oxidant Contaminants Treated Peroxide, Fenton’s Reagent TCA, PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1, 4 -dioxane, MTBE, tert-butyl alcohol, explosives Ozone (injected as gas PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, - sparging) MTBE, TBA, explosives Ozone + peroxide TCA, PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1, 4 -dioxane, MTBE, tert-butyl alcohol, explosives Permanganate (potassium or sodium) PCE, TCE, DCE, VC, BTEX, PAHs, phenols, explosives Activated Persulfate* PCE, TCE, DCE, VC, BTEX, chlorobenzene, phenols, 1, 4 -dioxane, MTBE, tert-butyl alcohol, pesticides *Activation by iron, hydrogen peroxide, heat, or high p. H (lime or Na. OH) 4

CHEMICAL OXIDATION – APPLICATION METHODS • • Direct push injection Fixed well injection In situ soil blending application Ex situ soil blending application 5

CHEMICAL REDUCTION • In 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. 6

CHEMICAL REDUCTION – APPLICATION METHODS Injection: • Direct injection • Hydraulic/pneumatic fracturing Placement: • Placement into trenches or excavations • Deep soil mixing 7

BIOLOGICAL • Aerobic and Anaerobic Remediation Methods • Uses 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) 8

AEROBIC BIOREMEDIATION - ORC • Addition 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 powder • Application methods – soil mixing/blending, direct injection, recirculating wells, direct placement into excavations or barrier walls. • In situ or ex situ applications. 9

ANAEROBIC BIOREMEDIATION • Addition 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 injections • Soil mixing • Placement into excavations 10

SPECIALTY SUPPLIERS AND PRODUCTS • Provides chemicals and specialized products. • Provides dosing and technical support during design. • Some companies can provide onsite field support during application. Example Companies Peroxy. Chem Regenesis Tersus Environmental Orin ISOTEC MECx 11

PROJECT EXAMPLE –CHEMICAL REDUCTION SOIL MIXING @ AN ARMY AMMUNITION PLAN • In 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. 12

THANK YOU 13