U#liza#on of of In- Situ Remedia#on

Transcription

1 U#liza#on of of In- Situ Remedia#on 2013 MWCC Environmental Conference Lake of the Ozarks, MO July 1, 2013 Derek D. Ingram, P.E., P.G.

2 Outline Site Closure Issues Why Consider In-situ Remediation Technologies Evaluation/Design Considerations Implementation Concerns/Considerations Summary 2

3 Magical Pixie Dust Does Not Exist 3

4 Ques#on What are the highest produced chemicals in U.S by volume? 1 sulfuric acid 2 nitrogen 3 ethylene 4 oxygen 5 propylene 6 chlorine 7 ethylene dichloride 8 phosphoric acid 9 ammonia 10 sodium hydroxide 11 benzene 12 nitric acid 13 ammonium nitrate 14 ethylbenzene 15 urea 16 styrene 17 hydrochloric acid 18 ethylene oxide 19 cumene 20 ammonium sulfate NOTE: Gasoline is highest produced product and is NOT included in this chemical lis#ng. 4

5 Common Remedia#on Issues Not all impact can be addressed through typical excavation methods Beneath a structure or building Extends to street, utility, or railroad right-of-way Depth beyond conventional equipment and approaches Groundwater control issues Landfill acceptance criteria Considered too large or too small of a project Facility or area of impact must remain operational 5

6 Why Consider In- situ Technologies? Can address areas not accessible to excavation Technologies can degrade wide suite of contaminants Result in non- or low-level concern terminal degradation products such as ethene, ethane and carbon dioxide Applicable to both vadose and saturated zones as well as different media 6

7 Why Consider In- situ Technologies? Some applications can be a rapid treatment, in order of days to months Controlled treatment process with little disturbance to site activities or community No longer new technologies, proven and acceptable solutions 7

8 Ques#on True or False: In-situ remediation is limited to four or five proven technological considerations? False.there a more than seventy-five in-situ technologies that have been used successfully and many more are considered new technology or in R&D status 8

9 In- Situ Remedia#on Technologies Soil Vapor Extraction (SVE) multi-phase extraction (MPE) Air Sparging (usually combined w/sve) hydrogen peroxide, CHP, Fenton s Reagent, Modified Fenton s, persulfate, permanganate, ozone, oxygen, proprietary products, many others Biostimulation/Bioaugmentation enhancement of existing conditions or introduction of new bacteria; aerobic and anaerobic conditions; supply a food source Chemical Reduction (ISCR) zero-valent metals, minerals, polysulfides, bimetallic materials; proprietary products 9

10 In- Situ Remedia#on Technologies Thermal (high and low temperature) electric resistance, air, water, steam, radio frequency, conduction, vitrification Soil Flushing (usually requires recovery and ex-situ treatment) Stabilization/Precipitation (most common with metals) Phytoremediation (most common with shallow metals) Surfactants (separation from media) 10

11 In- situ Remedia#on Technologies Permeable Reactive Barriers Prevent/reduce migration of groundwater plumes Common Technologies Zero Valent Iron (ZVI) Air Sparging Biological Chemical 11

12 MGP In- situ Technology Examples Location Media Technology Project Type Mid-Atlantic DNAPL Enhanced Vacuum Extraction Pilot NY Groundwater Oxygen Sparging Design Midwest Groundwater Precipitation Design IL Soil/Groundwater Persulfate Full-Scale Midwest DNAPL Passive Recovery Full-Scale IL Groundwater Hydrogen Peroxide Full-Scale Midwest Soil/Groundwater Ozone/Enhanced Bio Design IL Soil Catalyzed Hydrogen Peroxide Pilot MA DNAPL ERH Extraction Full-Scale CA Soil High-Temp Thermal Full-Scale SE US Soil Thermal - Steam Pilot VA Groundwater Permeable Reactive Barrier Full-Scale NY Soil/Groundwater Fenton s Reagent Full-Scale 12

13 Ques#on What is the half-life of benzene in groundwater? Can be as short as 10 days under ideal conditions or may exceed 720 days if highly anaerobic or the system cannot support biological growth. In comparison, benzene in soils has a bio reaction that is almostly entirely aqueous..therefore, if no biological growth is occurring in groundwater, it can be several years. 13

14 In- situ Evalua#on Often ignored as a primary remedial alternative Common misconception that it is a polishing approach only Does not allow test or debate on best and most cost-effective remedy Complete design/evaluation data not collected during characterization phase Timing of the remedial evaluation and schedule will impact the technology selection process May require additional delineation and/or characterization following other remedial activities Technology selection may require additional coordination or understanding with the regulators 14

15 Old Thinking: RI/FS Remedial Design Step 1 Step 2 Step 3 Step 4 Remedial Investigation Define Remedial Objective Feasibility Study Remedial Design Initial RI Collect Site Data Identify Receptors, Regulatory Requirements, etc. Evaluate Technologies Choose Technology Data Gap Analysis 15

16 New Thinking: Integrated Remedial Strategy Define Objective Depends on sensitivity of receptors, regulations, etc. Site Closure Define Criteria Set reasonable criteria to achieve goals Incorporate nonremediation approaches Remedial Investigation Focus RI to get data that support goal / criteria Feasibility Study Field Data to support design, bench, pilot study Remedial Design Choosing technology (or hybrids) to meet goals May be nonremediation approaches Have sights set on objective at the start, incorporate into every phase 16

17 Defining a Reasonable Objec#ve Difficult or cost-prohibitive to achieve Stringent / low numerical standards for soils MCL s in groundwater Remedial goals at every monitoring point More reasonable goals Contaminant mass reduction Reduction in groundwater concentrations Visible NAPL reduction / reduce NAPL migration Point of compliance (property boundary); # of points Incorporate risk assessments to establish site-specific targets Design for collection of data specific for technical impracticality demonstration 17

18 In- situ Evalua#on Characterization Data Preferred beyond typical logs and lab results NAPL density/specific gravity; viscosity; TPH Soils Non-target compounds in 10% to 20% of samples randomly across site (dosing ratios) TPH and TOC/foc from each strata Groundwater Field parameters of DO, ORP (typical are ph, temperature, conductivity, turbidity) Alkalinity, sulfate, dissolved and total iron/manganese From a subset: nitrate/nitrite, TDS, TSS, COD, bacteria standard plate count Hydrogeologic For each strata: hydraulic conductivity, gradient, average linear velocity Bulk density and effective/total porosity Vertical gradient 18

19 Keys to Evalua#on and Design Understand scavengers in addition to COCs metals, carbonates, nitrites, nitrates, sulfides, sulfates, foc, non-target contaminants, etc greatly affect consumption demand DO NOT IGNORE cumulative conditions For metals, it may not be the concentration, but often is the form. Establish a volume/cost scale (pound per pound) to compare approaches and technologies Must consider and design for treatment of degradation chain in addition COCs and scavengers may create a secondary situation of equal, greater, or less concern? Examples: vinyl chloride, ph, solubility 19

20 Keys to Evalua#on and Design Technical evaluation Consider and screen the array of potential technologies Bench testing DESIGN TOOL Obtain demand criteria Lesser need for cohesive soils; reactant dispersion and contact higher priority Pilot testing Obtain site condition performance criteria Defines multiple application Field scale Implement field pilot to full-scale Critical for Accurate Cost To Closure Determination 20

21 Which Would You Cross? Non-Bench Tested a.k.a. should hold Bench Tested a.k.a. designed to hold 21

22 Cost Effec#ve Sweet Spot for Organic Soil Remedia#on Technologies Contamina#on on Soil Technology Free Flowing Product Pore Filled Product >10,000 mg/kg > 1,000 mg/ Kg >100 mg/kg >1 mg/kg < 1 mg/kg Excava'on Extrac'on and Enhanced Extrac'on Soil Vapor Extrac'on (SVE) In Situ Chemical Oxida'on (ISCO) In Situ Chemical Reduc'on (ISCR) In Situ Bioremedia'on (ISB) Air Sparging (AS) Natural A@enua'on Thermal Enhancements Thermal enhancements could apply to several technologies including SVE and be applicable for higher concentra'ons of contamina'on. Table is intended to represent the best use of a technology. Most technologies may have benefit in other condi'ons. 22

23 Common Failure Causes Underestimating COC mass Bidders often low ball due to reduce initial cost compare pound to pound or $/cy and ask why? Scavengers Not addressing COC mass distribution Not identifying Contact Limitations Geology and/or chemical interactions that can impact ability to establish contact with contaminants Failure to adjust to changing site conditions The consequences of not fully conducting or understanding the evaluation process: Recontamination Rebound No apparent effect 23

24 In- situ Mee#ng the Objec#ve IP Baseline IP IP Post-application Coal tar impact addressed through ISCO IP

25 Ques#on Should proprietary products be considered in the design? ONLY if you ask a lot of questions (not site-specific, but often easily applied) Understand how it works and what it does. Active and inert ingredients are vaguely described as secret recipes Recommend bench scale and/or field demonstration INSIST on pound per product to pound per mass cost. 25

26 Summary In-situ technologies are proven, viable, scientific-based approaches that should be considered early in the project Evaluation with site-specific data is crucial (bench/pilot studies) Address scavengers Be prepared to account for changing site conditions (approach may require phased and/or differing technologies) Without a complete evaluation, the end result is often the design result..but not the anticipated result 26

27 Thank You! Questions? Derek D. Ingram, P.E., P.G. 27