Presentation on theme: "Young-Rainey STAR Centre Ross Towler & Robert Leather."— Presentation transcript:
Young-Rainey STAR Centre Ross Towler & Robert Leather
Introduction Site Description Contaminants Alternative Remediation Techniques Remediation Adopted Conclusion
Site Description Location –Pinellas County, Largo, Florida History –Formerly US DoE nuclear weapons research and development centre –End of the Cold War; stewardship and maintenance of the nation’s nuclear weapons –1999; Young-Rainey Science Technology and Research (STAR) Centre –houses more than 20 businesses that range from administrative to light manufacturing Environmental Restoration –Full cleanup of soil and groundwater contamination
Alternative Remediation Techniques In-situ Remediation Techniques Soil treatment without excavation and transportation Cost savings Longer time periods Non-uniformity of treatment Less certain results Ex-situ Remediation Techniques Contaminant treatment after excavation of soil Shorter time period Uniformity of treatment Greater costs Engineering Problems associated with excavation
Biological Remediation Processes What is it? Stimulation of micro organisms Contaminant used as food source & broken down Contaminant destroyed or transformed Organic contaminants only Low cost Why not for YRSC? Contaminant concentration too high (Initially) However… reduced current levels make Bioremediation a viable option.
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… oChemical Oxidation oElectrokinetic Remediation oSoil Flushing oSolidification/Stabilisation oSoil Vapour Extraction
Containment & Offsite Disposal Containment Migration of contaminant in soils/ground water prevented or significantly reduced Used in absence of realistic treatment option Does not lessen toxicity, mobility or volume of contaminant Offsite Disposal Contaminated material removed & transported to permitted off-site treatment and/or disposal facilities. Pretreatment usually is required Costly Disposal facilities uncommon Engineering problems associated with excavation
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 extraction Quick cleanup times, but generally costly Thermally enhanced SVE uses temperature to increase the volatility of the contaminants in the soils Similar to standard SVE, but requires heat resistant extraction wells.
Remediation Adopted (2) Preheat the perimeter of the remediation area Steam injection was used to form a steam barrier around the perimeter Evacuation of vapourised effluents from the system Treatment included heat exchange, separations, and carbon adsorption Why this technique? –Low permeability sediments –Presence of TCE, NAPL etc.
Conclusion Goals –Soil cleanup; TCE – 20.4 mg/kg –Groundwater cleanup; DCE – 50 mg/L Results –After 4.5 months of operation all soil and groundwater cleanup goals had been met Costs –total project subcontract cost was approximately $3,800,000