SAND No. 2010-3070 C 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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1. History and Types of Hazardous Waste Sites2. Discussion about Past Practices3. Remediation Technologies

• Containment Grout curtains, slurry walls, capping Monitoring

• Source Control (Soils, Sediments, Sludges) Pump and treat, Air/steam stripping, soil vapor

extraction Soil washing, solidification, mobile incineration

• Groundwater Treatment Carbon adsorption, bioremediation

Remediation of Hazardous Waste In-situ and Ex-situ Processes

SAND No. 2010-3070 C 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.

The Late 20th Century Became a Time to Focus on Man Made Pollution

SAND No. 2010-3070 C 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.

• 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

Surface and Groundwater Contamination Leads to Health Problems, Water Shortage

Textile Waste

Mining Waste

Gasoline

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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.

The History of Hazardous Waste Pollution

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Source: Wikipedia Superfund

Current

Proposed

Complete

Superfund Sites in the US

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Various Pathways Exist for Contamination From Land Disposal

SAND No. 2010-3070 C 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.

Solid Waste can Directly Impact Human Health

• Solvents – Gasoline, diesel, 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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Contaminated Land Disposal is Closely Linked to Water Cycle

SAND No. 2010-3070 C 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.

PathogensBacteria – Enteric, fecalProtists – Cysts and sporesVirus - Enteric

MetalsCopperLeadArsenic

Disinfection byproductsTrihalomethane - CHCl3,,CH2Cl2, CH2ClBrHaloacetic acid – CH2ClCO2H

Pesticides

Drinking Water, Wastewater Contaminants Directly Affect Public Health

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The larger the scope of contamination, the more limited the cleanup options.

After the pollutant has dispersed the groundwater may be undrinkable for years

Liability and funding for remediation may be quite expensive

General Lessons Learned in Remediating Hazardous Waste Sites

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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)

More Lessons Learned

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Containment: Seals off all possible exposure pathways between a hazardous waste disposal site and environment.

◦ Slurry Walls◦ Grout curtains◦ Drainage systems◦ Capping◦ Monitoring

Remediation can Take Various Pathways

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Basic Grout Curtain Containment SystemSlurry Wall

Slurry Walls and Grout Curtains are Containment Technologies

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Slurry Wall

• Dig trench around an area

• Backfill trench with an impermeable material (clay) slurry

Containment Remediation- Slurry Wall Emplaces Impermeable Barrier

Cross Section of a Slurry Wall

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Slurry Walls can be placed in a circular fashion to divert groundwater around contaminant

Slurry Walls are Impermeable Barriers Made of Clay Materials

Plan View Slurry Wall

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Grouting

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

Grout Curtains Injected in the Subsurface Solidification Reduces Permeability

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Downgradient Barrier and Extraction Wells (Top and Side Views) Upgradient Barrier and Extraction Wells

Containment Remediation Proceeds in Steps, Combined with Extraction

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Love Canal Barrier, Drain and Capping System

Love Canal Capping Containment and Drain

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All containment remedies are accompanied by an extensive groundwater monitoring.

Groundwater Monitoring is Necessary to Protect Drinking Water

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Different Technologies used for Groundwater Remediation

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Principally used to remove or reduce hazardous waste contamination from the groundwater aquifer passing through or near the site.

Pump and Treat (including lowering of GW table) Steam Stripping Air Stripping Carbon Adsorption Bioremediation

Groundwater Remediation Reduces Spread of Contamination

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Soil Vapor Extraction (SVE)Air SpargingBioremediation (including Bioventing and Bioreactors)Air Stripping and Steam StrippingSoil Washing and Soil FlushingStabilization/SolidificationVitrificationThermal DesorptionMobile Incineration

Source Control Prevents Continued Release or Spread of Contaminants

Used to remove or reduce hazardous waste contamination from sludges and soils near the site.

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Basic Pump and Treat System (Top and Side Views)

Pump and Treat

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Steam StripperAir Stripper

Air and Steam Stripping for Source Control

These can be used in conjunction with Soil Vapor Extraction or Groundwater Treatment

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Packed Tower Air Stripping System

Air Stripping Process - Water Treatment

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Typical Steam Stripping Flow Diagram

Steam Stripping Process – Water Treatment

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Fixed-bed Carbon Adsorption UnitCarbon Adsorption System

Carbon Adsorption - Water Treatment and Soil Vapor

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Different Technologies used for Soil Remediation

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• Volatiles swept from groundwater

• Optional air sparge

Soil Vapor Extraction (SVE)

• Volatiles captured or treated at surface

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Soil Vapor Extraction (SVE)

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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.

Air Sparging Enhanced SVE

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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.

• Bioventing has air flow rate lower than Soil Vapor Extraction (SVE) • deliver oxygen • minimizing volatilization.

• In-situ biological treatment is effective for non-halogenated volatiles and fuel hydrocarbons.

• Technology is less effective for non-biodegradable compounds and for soils with low permeability.

Bioremediation can Occur In-situ or Ex-situ

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• Use natural occurring and/or enhanced organisms

• Enhanced biotreatment involves add O2 and nutrients.

• Proper mixture of O2, nutrients and bacteria are site-specific and chemical-specific.

• Technique limited by pH, temp, toxicity of contaminants, and to aquifers with high permeability.

• Advantages:cost, minimal surface facilities minimal public exposure.

Biotreatment of Groundwater (In-situ)

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In-situ Bioremediation

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Ex Situ bioremediation involves excavating the contaminated soil

Placing it into biotreatment cells Adding nutrients to enhance biological activity Periodically turning it over to aerate the water. The moisture, heat, nutrients, oxygen, and pH

are usually controlled in the process. Separation of decontaminated solids

Bioremediation for Petroleum Waste (Ex-situ)

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Ex-situ Bioremediation for Petroleum Waste

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A variety of bacteria and yeast have been successfully deployed in situ and ex situ biological treatment systems.

Bioremediation Organisms

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Soil Washing: Ex-situ

• Excavation• Wash soil with leaching agent or surfactant• Not effective with clay or high organic content

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Soil Flushing : In-situ

• Apply water solution to enhance contaminant mobility• Generated leachate intercepted• 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.

Solidification – Stabilization (S/S)

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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.

Cement Stabilization (Ex-situ)

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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.

Pozzolanic Processes (Ex-situ)

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Generic Elements Of A Typical Ex-situ S/S Process

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S/S most commonly used for heavy metals and or cyanides.

Metals/Cyanide S/S Treatment Train

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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

In-situ Vitrification Process - Specialized S/S

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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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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.

Acknowledgement and Background

Richard Fortuna, President, Strategic Environmental Analysis, L.C.

www.richardfortuna.com

SEA.LLC@richardfortuna.com