Presentation on theme: "Young-Rainey STAR Centre"— Presentation transcript:
1 Young-Rainey STAR Centre Ross Towler & Robert Leather
2 Introduction Site Description Contaminants Alternative Remediation TechniquesRemediation AdoptedConclusion
3 Site Description Location History Environmental Restoration Pinellas County, Largo, FloridaHistoryFormerly US DoE nuclear weapons research and development centreEnd of the Cold War; stewardship and maintenance of the nation’s nuclear weapons1999; Young-Rainey Science Technology and Research (STAR) Centrehouses more than 20 businesses that range from administrative to light manufacturingEnvironmental RestorationFull cleanup of soil and groundwater contamination
5 Alternative Remediation Techniques In-situ RemediationTechniquesSoil treatment without excavation and transportationCost savingsLonger time periodsNon-uniformity of treatmentLess certain resultsEx-situ RemediationTechniquesContaminant treatment after excavation of soilShorter time periodUniformity of treatmentGreater costsEngineering Problems associated with excavation
6 Biological Remediation Processes What is it?Stimulation of micro organismsContaminant used as food source & broken downContaminant destroyed or transformedOrganic contaminants onlyLow costWhy not for YRSC?Contaminant concentration too high (Initially)However… reduced current levels make Bioremediation a viable option.
7 Physical/Chemical Treatment Physical/Chemical treatment uses the physical properties of the contaminants or the contaminated medium to destroy (i.e., chemically convert), separate, or contain the contamination.Examples…Chemical OxidationElectrokinetic RemediationSoil FlushingSolidification/StabilisationSoil Vapour Extraction
8 Containment & Offsite Disposal Migration of contaminant in soils/ground water prevented or significantly reducedUsed in absence of realistic treatment optionDoes not lessen toxicity, mobility or volume of contaminantOffsite DisposalContaminated material removed & transported to permitted off-site treatment and/or disposal facilities.Pretreatment usually is requiredCostlyDisposal facilities uncommonEngineering problems associated with excavation
9 In Situ Thermal Treatment Techniques Steam/hot air injection, electrical resistance or other means used to increase the volatilisation rate of semi-volatiles and facilitate extractionQuick cleanup times, but generally costlyThermally enhanced SVE uses temperature to increase the volatility of the contaminants in the soilsSimilar to standard SVE , but requires heat resistant extraction wells.
10 Remediation Adopted Soil Media In-situ thermal enhanced soil vapour extraction techniqueSteam Enhanced Extraction and Electro-Thermal Dynamic Stripping Process (ET-DSP™)Steam injection wellsExtraction wellsET-DSP™ electrodes
11 Remediation Adopted (2) Preheat the perimeter of the remediation areaSteam injection was used to form a steam barrier around the perimeterEvacuation of vapourised effluents from the systemTreatment included heat exchange, separations, and carbon adsorptionWhy this technique?Low permeability sedimentsPresence of TCE, NAPL etc.
12 Conclusion Goals Results Costs Soil cleanup; TCE – 20.4 mg/kg Groundwater cleanup; DCE – 50 mg/LResultsAfter 4.5 months of operation all soil and groundwater cleanup goals had been metCoststotal project subcontract cost was approximately $3,800,000