Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company,
for the United States Department of Energy’s National Nuclear Security Administration
under contract DE-AC04-94AL85000.
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History and Types of Hazardous Waste Sites
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Discussion about Past Practices
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Remediation Technologies
• Containment
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Grout curtains, slurry walls, capping
Monitoring
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Pump and treat, Air/steam stripping, soil vapor extraction
Soil washing, solidification, mobile incineration
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Carbon adsorption, bioremediation
Source Control (Soils, Sediments, Sludges)
Groundwater Treatment
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Mining
• Acid mine drainage
• Heavy metals – Hg, Cr, Pb
Industrial / Commercial Pollution
• Dyes and pigments
• Petroleum / gasoline
Agricultural runoff
• Pesticides
• Nutrients – nitrates, phosphates
• Salinization – Sodium, chloride
Sewage
• Pathogens - Enteric
• Nutrients – Nitrates, phosphates
• Contaminated animal feed
Textile Waste
Gasoline
Mining Waste
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In 1962, renowned author and naturalist, Rachel
Carson, warned growing contamination “great
underground seas” (i.e., groundwater) in “Silent
Spring.”
Love Canal – New York, USA. Buried barrels of
chemicals underneath new housing development
(1950s). Became main cause for the Superfund
legislation. Removed from Superfund in 2004.
Valley of the Drums – Kentucky, USA, 23 acre site with
a large number of leaking drums. Fire at site in 1966.
Not completely cleaned up until 1990.
Times Beach – Missouri, USA community where
contaminated oil was used for dust control from
1972-1975.
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Current
Proposed
Complete
Source: Wikipedia Superfund
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‣ Solvents – Gasoline, diesel,
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chlorinated
Leachates – Acid waste, heavy
metals
Hazardous waste – Metals,
paints, solvents, pesticides
Leaking fuel tanks – Gasoline,
diesel
Refuse - Decaying animal and
plant matter
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Pathogens
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Metals
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Disinfection byproducts
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Pesticides
• Bacteria – Enteric, fecal
• Protists – Cysts and spores
• Virus - Enteric
• Copper
• Lead
• Arsenic
• Trihalomethane - CHCl3,,CH2Cl2,
CH2ClBr
• Haloacetic acid – CH2ClCO2H
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The larger the scope of contamination, the more
limited the cleanup options.
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After the pollutant has dispersed the groundwater
may be undrinkable for years
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Liability and funding for remediation may be quite
expensive
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Cleanup is much more costly and time consuming than
properly managing wastes in the first place.
• Treatment and excavation costs
• Continuous expense for monitoring
 Landfills, lagoons, piles and land spreading will often
create large areas of contamination
 Chlorinated solvents are often high density and thus will
“sink” toward groundwater. (DNAPL)
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Containment:
Seals off all possible exposure pathways
between a hazardous waste disposal site and
environment.
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Slurry Walls
Grout curtains
Drainage systems
Capping
Monitoring
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Slurry Wall
Basic Grout Curtain Containment System
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Slurry Wall
• Dig trench around an area
• Backfill trench with an
impermeable material (clay)
slurry
Cross Section of a Slurry Wall
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Slurry Walls can be placed
in a circular fashion to
divert groundwater around
contaminant
Plan View Slurry Wall
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Grouting
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Inject liquid, slurry, or emulsion under pressure into the soil
Slury fills pore space
Two types
• Particulate – solid + liquid solidifies
• Chemical – Liquid +liquid that gels
Grouts are limited when high water table or rapid GW flow
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Downgradient Barrier and
Extraction Wells (Top and Side
Views)
Upgradient Barrier and
Extraction Wells
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Love Canal Barrier, Drain and Capping System
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All containment remedies are accompanied by an
extensive groundwater monitoring.
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Principally used to remove or reduce hazardous waste
contamination from the groundwater aquifer passing through
or near the site.
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Pump and Treat (including lowering of GW table)
Steam Stripping
Air Stripping
Carbon Adsorption
Bioremediation
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Used to remove or reduce hazardous waste
contamination from sludges and soils near the site.
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Soil Vapor Extraction (SVE)
Air Sparging
Bioremediation (including Bioventing and Bioreactors)
Air Stripping and Steam Stripping
Soil Washing and Soil Flushing
Stabilization/Solidification
Vitrification
Thermal Desorption
Mobile Incineration
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Basic Pump and Treat System (Top and Side Views)
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Steam Stripper
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Air Stripper
These can be used in conjunction with Soil
Vapor Extraction or Groundwater Treatment
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Air Stripping System
Packed Tower
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Typical Steam Stripping Flow Diagram
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Fixed-bed Carbon Adsorption Unit
Carbon Adsorption System
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•Volatiles swept from
groundwater
•Optional air sparge
•Volatiles captured or
treated at surface
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SVE commonly enhanced with air
sparging.
Air sparging involves the active
pumping of ambient air into the
subsurface soil and groundwater to
enhance the collection of volatiles
through the SVE system.
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In-situ typically enhances naturally occurring biological activity
• circulating nutrient and oxygen-enriched water-base solution
• forced air movement provides oxygen to enhance naturally
occurring microbes.
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Bioventing has air flow rate lower than Soil Vapor Extraction (SVE)
• deliver oxygen
• minimizing volatilization.
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In-situ biological treatment is effective for non-halogenated
volatiles and fuel hydrocarbons.
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Technology is less effective for non-biodegradable compounds and
for soils with low permeability.
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Use natural occurring and/or
enhanced organisms
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Enhanced biotreatment involves
add O2 and nutrients.
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Proper mixture of O2, nutrients
and bacteria are site-specific and
chemical-specific.
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Technique limited by pH, temp,
toxicity of contaminants, and to
aquifers with high permeability.
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Advantages:cost, minimal surface
facilities minimal public exposure.
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Ex Situ bioremediation involves excavating the
contaminated soil
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Placing it into biotreatment cells
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Adding nutrients to enhance biological activity
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Periodically turning it over to aerate the water.
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The moisture, heat, nutrients, oxygen, and pH are
usually controlled in the process.
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Separation of decontaminated solids
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A variety of bacteria and yeast have
been successfully deployed in-situ
and ex-situ biological treatment
systems.
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• Excavation
• Wash soil with leaching agent or surfactant
• Not effective with clay or high organic content
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Apply water solution to enhance contaminant mobility
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Generated leachate intercepted
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Especially good for halogenated and high permeability soil
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Solidification methods physically encapsulate
hazardous waste into a solid material matrix of
high structural integrity.
Stabilization techniques chemically treat hazardous
waste by converting them into a less soluble,
mobile or toxic form.
• Principally used for metal-bearing wastes.
• Limited applicability to organic wastes.
• Typically used to concentrate contaminants prior to
S/S.
• 2 Main types of processes: cement and pozzolanic.
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Description
• Slurry of wastes and water is mixed with portland cement to
form a solid.
Advantages
• Low cost
• Readily available mixing equipment
• Relatively simple process
• Suitable for use with metals
Disadvantages
• Solids are suspended, not chemically bound
◦ subject to leaching
• Doubles waste volume
• Requires secondary containment
• Incompatible with many wastes
◦ Organics, some sodium salts, silts, clays, and coal or lignite.
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Description
• Waste is chemically reacted with lime and a fine-grained
siliceous material (fly ash, ground blast furnace slag,
cement kiln dust) to form a solid.
Advantages
• Low costs;
• Readily available mixing equipment;
• Suitable for power-plant wastes (FGD sludges, etc.) as well
as a wide range of industrial wastes, including metals,
waste oil, and solvents
Disadvantages
• Increases waste volume
• May be subject to leaching
• Requires secondary containment.
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Solidification - Stabilization
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S/S most commonly used for heavy metals and or cyanides.
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Thermal process converts contaminated soil to chemically
inert stable glass/crystalline product.
• Electrical current produces heat –melts soil
• Molten zone grows destroying/encapsulating hazardous constituents and
metals
• Hood for volatile emissions
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• Involves a wide variety of units such
as small liquid waste incinerators at
right.
• Multiple trailer rotary kiln for
complex sludges and drummed
waste, below.
• Infrared (electrically heated) “soil
roaster” are also used. Infrared is a
form of indirect heating using
electric current instead of fuel oil to
generate heat.
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Richard Fortuna, President, Strategic
Environmental Analysis, L.C.
www.richardfortuna.com
SEA.LLC@richardfortuna.com
• 31 years experience evaluating technologies and developing preventive
policies for HW management
• Developed key provisions of the U.S. statute governing daily waste
management; The Resource Conservation and Recovery Act (RCRA)
• Participated in enactment of the “Superfund” cleanup law. RCRA is
intended to prevent the creation of additional “Superfund” or leaking
waste sites
• Worked with over 200 companies in evaluating waste treatment
technologies and policies
• Authored a text on major reforms to RCRA.
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