1. www.urscorp.com www.regenesis.com Field-Scale Application of in situ Reductive Dechlorination for High Concentrations of Mixed Solvents in Complicated Conditions – Northern France Dr Richard Sumner – URS Corporation (Paris) Dr Jeremy Birnstingl – Regenesis Ltd. (UK)

2. www.urscorp.com www.regenesis.com Background Former Dry Cleaner Site Contaminated area: 1.000 m 2 Representative concentrations Chlorinated ethenes (TCE etc) – 20.000 µg/L Chlorinated ethanes (TCA etc) – 10.000 µg/L Chlorinated methanes (DCM) – 5.000 µg/L Buildings covering ~50% of plume

3. www.urscorp.com www.regenesis.com Complications Practical – access and disturbance Geotechnical – risk of subsidence Geological – risk of pathway exacerbation Public health – proximity of human receptors Requirement to ensure full dechlorination (no VC stall)

4. www.urscorp.com www.regenesis.com Practical Complications Built-up area – noise / nuisance concerns 50% of plume located beneath site buildings Source zone adjacent to residential properties

5. www.urscorp.com www.regenesis.com Geotechnical Complication Dual Phase Extraction initially considered Geotechnical assessments undertaken Risk of fines wash-out leading to subsidence Advection-based in situ remediation high risk Diffusive in situ remediation selected – HRC ®

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8. www.urscorp.com www.regenesis.com Source Area

9. www.urscorp.com www.regenesis.com Source area adjacent to occupied residential properties Disturbance issues Risk / receptor issues Subsidence issues – overcome by selection of passive technology Measures adopted: Vadose vapour monitoring and venting installation Noise monitoring and management during injection TCE ≤ 20.000 µg/L TCA ≤ 10.000 µg/L DCM ≤ 5.000 µg/L

10. www.urscorp.com www.regenesis.com Hydrogen Release Compound ®

11. www.urscorp.com www.regenesis.com Formation of an Ester Glycerol Polylactate Ester = HRC ®

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14. www.urscorp.com www.regenesis.com Why? Accelerated Remedial Closure: Hydrogen creates anaerobic plume and accelerates biodegradation 10x – 100x Time Release of Hydrogen saves money: Reduced installation costs (simple to apply) NO remedial hardware: Design costs Equipment capital costs Equipment O&M costs Ongoing site disturbance

15. www.urscorp.com www.regenesis.com Geological Complication Shallow gravelly silt 0.75 – 3.0 mbgl Medium permeability Heavy contamination Silty sand layer 3.0 – 5.5 mbgl Low permeability Medium contamination Coarse gravels 5.5 – 10 mbgl High permeability Low – medium contamination (still requires treatment) Risk of Pathway Creation – 92 HRC ® injection points

16. www.urscorp.com www.regenesis.com Solution: ‘Top down’ and ‘bottom up’ injection

17. www.urscorp.com www.regenesis.com (block figure of geology?)

18. www.urscorp.com www.regenesis.com Application by GeoProbe ®

19. www.urscorp.com www.regenesis.com HRC ® directly injected using grout pump 41 kg HRC per point 92 injection points 6 vertical metres ~ 0.15% of pore volume Easy injection, minimal hydrogeological disruption

20. www.urscorp.com www.regenesis.com Noise Monitoring

21. www.urscorp.com www.regenesis.com Treatment Results Predicted results (theory based on other sites) Actual results (field performance of this site)

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23. www.urscorp.com www.regenesis.com Results – predicted

24. www.urscorp.com www.regenesis.com Results – actual (Cl-ethenes)

25. www.urscorp.com www.regenesis.com Results – actual (Cl-ethenes)

26. www.urscorp.com www.regenesis.com Results – actual (Cl-ethenes)

27. www.urscorp.com www.regenesis.com Results – actual (Cl-ethanes)

28. www.urscorp.com www.regenesis.com Results – actual (Cl-ethanes)

29. www.urscorp.com www.regenesis.com Results Summary TCE Concentrations (µg/L)TCA Concentrations (µg/L) WellDay 0Day 430% Red.WellDay 0Day 430% Red. PP-168000.6>99%PP-1780999% PW1371073%PW1380081079% PW2480011098%PW2820068>99% PW341198%PW3260698% PW6120100%PW656160 (increase)

30. www.urscorp.com www.regenesis.com Results – actual (Cl-methanes) Chloromethane non-detect throughout study (both wells)

31. www.urscorp.com www.regenesis.com Dichloromethane (DCM) Results Well PZ3 /PZ3bisWell PW2 Dateµg/LDateµg/L Oct-036100Oct-033900 Dec-031500Dec-03220 Jan-040.1Jan-040.1 Feb-041300Feb-04350 Mar-044000Mar-04520 Apr-043400Apr-04160 May-043200May-0492 Jun-041400Jun-0415 Aug-04(no data)Aug-0426 Oct-04550Oct-0428 % Reduction91% Reduction99%

32. www.urscorp.com www.regenesis.com Cost Comparisons Total HRC project cost approx. €300.000 (Fieldwork, 2 years monitoring and reporting, HRC material) Comparative dual-phase extraction cost approx. €400.000 - €500.000 €100.000 system installation €100.000 per year O&M for 3-4 years HRC project presented 25% - 40% cost saving (Faster too?)

33. www.urscorp.com www.regenesis.com Project Status Currently frozen Client went into liquidation All activities on hold But discussions now restarting

34. www.urscorp.com www.regenesis.com Currently frozen Client went into liquidation All activities on hold But discussions now restarting Project Status

35. www.urscorp.com www.regenesis.com Technology Applicability in France Closing Comments (URS) 1.A great, “text book” reductive dechlorination case study 2.HRC worked very well – it has a place in the remedial tool kit 3.Would reach for this technology where machinery is impractical for reasons of noise and space, fouling (e.g. sparging, drip-feed donors) or wash-out / subsidence concerns, (and in low-permeability formations - Regenesis). 4.Also valuable where on-going operation is not attractive – ‘one-off’ field installation provides maintenance-free remediation for several years

36. www.urscorp.com www.regenesis.com Closing Statistics This was the first HRC application in France Also the first full scale reductive dechlorination project in France? URS have completed approx. 30 HRC projects worldwide out of more than 100 projects using Regenesis products Total worldwide HRC projects is > 1.500 – HRC is the most widely used electron donor in the world Largest URS HRC project (currently underway) is 81.500 kg in US – >ten times larger (presented project is ca. 7.000 kg) URS therefore offer significant corporate experience with this technology in France, Europe, and internationally Regenesis provide free technical support and project assistance

37. www.urscorp.com www.regenesis.com For More Information: URS Corporation (Paris) Dr. Richard Sumner +33 (0)1 55 69 20 45 richard_sumner@urscorp.com www.urscorp.com Regenesis Ltd. (UK) Dr. Jeremy Birnstingl +44 (0)1225 722 716 jbirnstingl@regenesis.com www.regenesis.com