RECENT USES OF IN SITU STABILIZATION, IN SITU CHEMICAL OXIDATION, AND IN SITU CHEMICAL REDUCTION USING SOIL MIXING. RE3 Remediation, Renewal, Results

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1 RECENT USES OF IN SITU STABILIZATION, IN SITU CHEMICAL OXIDATION, AND IN SITU CHEMICAL REDUCTION USING SOIL MIXING Presented by: Ken Andromalos & Daniel Ruffing RE3 Remediation, Renewal, Results

2 Soil Mixing Development Timeline First Used in US: Geotechnical and Earth Retention Applications Re-introduced into US market: Jackson Lake Dam Expanded use on environmental sites for stabilization & treatment Developed in Japan and Europe First used for Solidification / Stabilization of wastes

3 Soil Mixing Any technique used to mechanically mix soils with or without additives More commonly, the term refers to processes by which reagents are injected and mixed with the soil Processes vary: In Situ vs. Ex Situ Dry vs. Wet Reagent Addition Single Auger vs. Multi Auger Auger vs. Bucket vs. Rotary Drum Purpose : the efficient creation of a soil-reagent composite with improved properties relative to the in situ soils.

4 Soil Mixing Background Conclusions Widely accepted means for cost effective site remediation Other related acronyms: Shallow Soil Mixing (SSM) Deep Soil Mixing (DSM) Stabilization & Solidification (S/S) In Situ Stabilization (ISS) In Situ Solidification (ISS) In Situ Chemical Oxidation (ISCO) In Situ Chemical Reduction (ISCR)

5 Soil Mixing Equipment for Environmental Applications Auger Mixing Excavator Mixing Excavator Mounted Rigs Or Buckets Or Crane Mounted Rigs Arm Attachments

6 Auger Mixing Auger mixing most commonly used soil mixing method for environmental projects Generally the most cost effective auger mixing for environmental applications is large diameter single auger mixing (pictured here)

7 Auger Mixing general aspects Columns installed in an overlapping pattern that ensures 100% coverage of the target area Wet mixing is more common for environmental applications, but occasionally project or site conditions neccesitate the use of dry mixing methods or the use of air as a drilling fluid

8 Solidification vs. Treatment Solidification / Stabilization (ISS) Contaminants are not purposefully chemically changed to less harmful forms, but are locked in low permeability matrices that reduce the contaminants impact on the surrounding soils and groundwater. Treatment (IST) Reagents are used to actively promote a chemical change in the impacted material Contaminants are purposefully chemically changed to less harmful constituents via reduction or oxidation

9 Reagents Sources: ITRC (2011)[6]; Gardner, F.G., et. al., (1998)[8]; Irene M.C., (1996)[9]; USEPA (2009)[10]; U.S Department of Defense (2000)[11]; U.K Environmental Agency (2004)[12]; Raj, D.S.S; Rekha, C.A.P, Bindhu, V.H; Anjaneyulu, Y., (2005)[13]; Conner, (1990) [14].

10 Solidification vs. Treatment conclusions ISS generally cheaper than IST Lower reagent cost Less material handling safety concerns Similar schedules Both viewed as acceptable remediation approaches, but IST often viewed as a more robust solution Promotes active degradation of contaminants Require similar equipment and labor, but IST projects are harder to implement Project staging more difficult Material handling more difficult

11 Case Studies - Introduction Case Study 1 East Rutherford, NJ In situ chemical oxidation and stabilization of solvent impacted soils Case Study 2 Robbinsville, NJ In situ chemical oxidation of xylene & pesticide impacted soils Case Study 3 Waukegan, IL In situ chemical reduction of solvent impacted soils Case Study 4 Norwich, NY In situ chemical oxidation of acetone impacted soils Case Study 5 Columbus, IN In situ stabilization / solidification of wood treating impacted soils

12 Case Study 1 East Rutherford, NJ Original site use: Glassware manufacturing facility Contaminant of Concern TCE and related byproducts Performance Schedule Bench Scale Study: Fall 2009 Site Prep Work: Spring 2010 Soil Mixing: Spring Summer 2010 Treated Volume Dimensions 6,800 CYs treated twice (13,600 CYs total) Up to 20 BGS Reagents Potassium 17.5 lbs / CY Portland 202 lbs / CY (applied 3 days post oxidation)

13 Case Study 1 East Rutherford, NJ (2) Potassium permanganate is bright purple at very low concentrations material handling was a big part of the project. Work performed in a bowl to control spoils A number of obstructions were removed, including deep foundations

14 Case Study 1 East Rutherford, NJ (3) 242 nine foot diameter columns installed Quality Control Post construction groundwater monitoring showed 99% reduction in TCE concentration Wet grab samples were collected from recently mixed columns Average UCS = ~ days Average Permeability = 4.1 x days

15 Case Study 2 Robbinsville, NJ Original site use: Chemical manufacturing facility Contaminant of Concern Xylene and pesticides Performance Schedule Soil Mixing: Summer 2011 Treated Volume Dimensions 2,500 CYs Up to 15 BGS Reagents Hydrated 72 lbs / CY (ph adjustment) Sodium 28 lbs / CY (oxidant)

16 Case Study 2 Robbinsville, NJ (2) The oxidation reaction was evident at the surface as the material bubbled and changed colors Work performed in a bowl to control spoils Project staging important because of post treatment soil properties

17 Case Study 2 Robbinsville, NJ (3) 91 nine foot diameter columns installed Quality Control Process controls were utilized to ensure the proper amounts of reagents were added to and mixed with the soils

18 Case Study 3 Waukegan, IL Original site use: Outboard marine engine manufacturing Contaminant of Concern TCE and related byproducts (vinyl chloride) Performance Schedule Soil Mixing: Fall Winter 2011 Treated Volume Dimensions 7,800 CYs Up to 25 BGS Reagents Zero Valent Iron 54 lbs / CY Bentonite 27 lbs / CY

19 Case Study 3 Waukegan, IL (2) The ZVI soil mixing work was the first part of a much larger remediation effort at this Superfund site. The soil mixing was used to target the source zone. Potassium permanganate is bright purple at very low concentrations material handling was a big part of the project. Iron storage very important prevent rust! The sands and gravels presented very difficult drilling conditions

20 Case Study 3 Waukegan, IL (3) 224 nine foot diameter columns installed Quality Control Samples of mixed material were subjected to magnetic seperation tests to ensure the iron was well distirbuted. Post construction sampling for TCE concentration to be conducted later.

21 Case Study 4 Norwich, NY Original site use: Chemical manufacturing Contaminant of Concern Acetone Performance Schedule Soil Mixing: Winter Spring 2012 Treated Volume Dimensions 19,500 CYs Up to 30 BGS Reagents Post hot air mixing Ammonium 0.5 lbs / CY Potassium 0.25 lbs / CY Phosphoric 18 lbs / CY Calcium 21.5 lbs / CY

22 Case Study 4 Norwich, NY (2) Project staging was very important given the liquid consistency of the soils post treatment. Work Two drill performed rigs used in a throughout bowl to control the project. The first rig was used for hot air mixing and the second spoils rig was used to add and mix in the chemical reagents

23 Case Study 4 Norwich, NY (3) 324 nine foot diameter columns installed Quality Control Process controls were utilized to ensure the proper amounts of reagents were added to and mixed with the soils Post construction sampling to be conducted

24 Case Study 5 Columbus, IN Original site use: Wood treating Contaminant of Concern Creosote Performance Schedule Soil Mixing: Spring 2012 Treated Volume Dimensions 4,600 CYs Up to 17 BGS Reagents Portland 480 lbs / CY Powered Activated Carbon 120 lbs / CY

25 Case Study 5 Columbus, IN (2) Powdered carbon delivered in supersacks Automated batch plant for proportioning grout components Carbon Work Two drill performed combined rigs used in with a throughout bowl creosote to control gave the project. the The first rig was used for hot air mixing material and thesecond spoils it s dark rig color was used to add and mix in the chemical reagents

26 Case Study 5 Columbus, IN (3) 247 nine foot diameter columns installed Quality Control Wet grab samples were collected immediately after mixing

27 Conclusions Soil Mixing Widely used to treat & stabilize a number of wastes Stabilization vs. Treatment Stabilization less expensive, but contaminants remain relatively chemically unchanged Numerous reagents for both stabilization and treatment Case Studies Recent case studies highlight the use of soil mixing for the treatment and stabilization of subsurface contamination Material handling and storage very important Careful planning and staging required