1. www.benkeet.com ©2006 Ben Keet 1 Cost – performance curves A tool to evaluate alternative remedial options before and during projects

2. www.benkeet.com ©2006 Ben Keet 2 Background Drs Ben Keet Free University of Amsterdam : Physics & Hydrogeology Work experience 5 years Ass. Lect. Physics & Groundwater Models 5 years Shell International : UK, Algeria, Gabon, London 19 years Geo & Hydro: New Zealand, Australia, US, Europe, NZ  Proj. manager 2500 site assessments, 1500 remediations  Design & manage : 400 in situ & biological remediations

3. www.benkeet.com ©2006 Ben Keet 3 CP curves: Conditions of use Good understanding of uncertainties involved Thorough knowledge of effects of remedial techniques to be evaluated Cost estimates need to be complete Accurate and relevant monitoring data

4. www.benkeet.com ©2006 Ben Keet 4 What we know is not much What we know we don’t know is limited But what don’t we know we don’t know ? Uncertainties keep in mind:

5. www.benkeet.com ©2006 Ben Keet 5 Groups of Uncertainties 1.Initial conditions 2.Effect of chosen remedial technique(s) 3.Quality of implementation 4.Technical uncertainties 5.Contractual uncertainties

6. www.benkeet.com ©2006 Ben Keet 6 Initial conditions  Heterogeneity :  Soil  Contaminants  Time  Contaminant movement  Retardation (actual)  Leaching (TCLP)  (Re-) mobilisation

7. www.benkeet.com ©2006 Ben Keet 7 Effect of chosen remedial technique(s) - Breakdown speed (half-life time) - The natural or enhanced breakdown potential - Leaching / migration potential (current, during and after remedial action) - Lowest possible attainable concentration by mixing or bioremediation

8. www.benkeet.com ©2006 Ben Keet 8 Quality of implementation  Focus on results  Use soil heterogeneity  Monitoring aimed at  System check  Process control  Effect monitoring  So not only Verification

9. www.benkeet.com ©2006 Ben Keet 9

10. www.benkeet.com ©2006 Ben Keet 10 Technical uncertainties Just a few: Presence of sulphides – acid soils Change of redox – mobilisation (As) NA of VOCl’s formation of VC (gas)

11. www.benkeet.com ©2006 Ben Keet 11 Contractual uncertainties  Definition of goals vs. definitions of the deliverables  Final sampling methodology  Allowable residual risk / contaminants  Ownership intellectual property

12. www.benkeet.com ©2006 Ben Keet 12 Cost – performance curves Case - midpoint evaluation -oil spill ½ under glass house -Emergency response : -Dig trench -Pump fluid to oil/water separator -After 21 months evaluate alternatives

13. www.benkeet.com ©2006 Ben Keet 13 4 scenarios: 0 = no added activity I, II, III = addition of several in situ techniques

14. www.benkeet.com ©2006 Ben Keet 14 Set out cost vs. kg contaminant removed Conclusion: Simplest system will eventually remove same oil mass at lowest costs

15. www.benkeet.com ©2006 Ben Keet 15 Now evaluate S/kg in time

16. www.benkeet.com ©2006 Ben Keet 16 Conclusions this Case With the added knowledge of hint sight: In this case 1.Full excavation immediately after spill gives highest cost efficiency 2.Note added cost to shut down operations 3.Plus cost for demolition / rebuilding glass house

17. www.benkeet.com ©2006 Ben Keet 17 Conclusion CP curves 1.Allows technique independent comparison 2.Easy to explain to lay person However: 1.Requires thorough insight in techniques 2.Requires firm costing of alternatives 3.Requires identification of residual uncertainties

18. www.benkeet.com ©2006 Ben Keet 18 Questions - Discussion