DNAPL (DDT, CB) Remediation 

200 year-old Manufacturing Site in Pennsylvania

ENVIRONMENTAL

REMEDIATION

SERVICES &

PRODUCTS

SITE HISTORY

  • Over 200 years of on-site chemical manufacturing

  • Multi-component DNAPL present at fill-native clay interface

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Chlorinated Contaminants & Mass
Concentrations as % of Total COCs

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INITIAL BENCH STUDY

  • Cool-Ox® Selected:

  • Both Cool-Ox® and heat activated sodium persulfate achieved >80% COC destruction

  • Cool-Ox® was selected as the oxidizing and reducing agent because no activation was required.

SUPPLEMENTARY BENCH SCALE TEST

  • Selectivity of ISCO/ISCR treatment? Or

  • Distribution of alkanes in fine-grain matrix?

  • What about dose-response?

  • Optimum pH 8-9.5

DOSE RESPONSE

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WORKING SAFELY

  • 9,020 safe work hours under adverse weather conditions (snow/sleet) and subzero temperatures

  • Incident-free completion

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“Outstanding achievement! An unannounced internal audit with nothing but positive findings!


This is a true demonstration of your strong EH&S culture and leadership.


Thank you all for living and working safely!”


- EH&S Remediation Manager - Global Remediation Business

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PILOT DEMONSTRATION RESULTS

Relative Mass Relationships Before & After Pilot
Primary COCs              Before          Reduced by
Chlorobenzenes:              51%                   73%
Total DDX:                        34%                   86%
1,2-Dichloropropane:        8%                     72%

FULL-SCALE TREATMENT

As designed:

  • 1,766 injection points on 6’x6’ grid

  • First dosing rate selected based on chemical costs and field mobilization costs

  • First dosing aimed at 80% COC mass removal at locations with 7,500 mg/kg COC or less

  • Field results indicated reagent dosage rates limited by subsurface acceptance

  • 10 subareas found to require second treatment

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As Implemented:

  • 2,072 injection points (primary, secondary combined)

  • 154,260 gallons of Cool-Ox® injected

  • 10,284 injected linear feet

  • Reduced COC mass by 67% (311,000 pounds)

  • Overcome acid soil conditions

  • Proved “Big-Sites” can be treated with ISCO/ISCR

  • Pre-planned injection sequence avoided need to remobilize injection rig

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Cool-Ox® Foaming Reaction

CONCLUSION

  • Primary injection reduced subsurface COC mass by 64%

  • Secondary Injections destroyed over 311,000 lbs. of DDT, DDX, CB, BCEE (reduced COC mass by 67%) in 4.5 months - URS data

  • The total DNAPL mass destroyed was over 305,000 lbs.

  • 3 grams COC removal per gram Cool-Ox® (slightly better than predicted by bench study!)