Скачать презентацию Cost performance curves A tool to evaluate Скачать презентацию Cost performance curves A tool to evaluate

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

Background Drs Ben Keet Free University of Amsterdam : Physics & Hydrogeology Work experience Background Drs Ben Keet Free University of Amsterdam : Physics & Hydrogeology Work experience • • • Ø Ø 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 www. benkeet. com 2

CP curves: Conditions of use • Good understanding of uncertainties involved • Thorough knowledge 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 www. benkeet. com 3

Uncertainties keep in mind: What we know is not much What we know we Uncertainties keep in mind: 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 ? www. benkeet. com 4

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

Initial conditions § Heterogeneity : § Soil § Contaminants § Time § Contaminant movement Initial conditions § Heterogeneity : § Soil § Contaminants § Time § Contaminant movement § Retardation (actual) § Leaching (TCLP) § (Re-) mobilisation www. benkeet. com 6

Effect of chosen remedial technique(s) • - Breakdown speed (half-life time) • - The 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 www. benkeet. com 7

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

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

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

Cost – performance curves Case - midpoint evaluation - oil spill ½ under glass 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 www. benkeet. com 12

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

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

Now evaluate S/kg in time www. benkeet. com 15 Now evaluate S/kg in time www. benkeet. com 15

Conclusions this Case With the added knowledge of hint sight: In this case 1. 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 www. benkeet. com 16

Conclusion CP curves 1. Allows technique independent comparison 2. Easy to explain to lay 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 www. benkeet. com 17

Questions - Discussion www. benkeet. com 18 Questions - Discussion www. benkeet. com 18