1. Environmental Geotechnology Presentation Naval Air Station, Pensacola, Florida

2. Naval Air Station

3. Introduction  Naval Air Station  5,800 acres  3km southwest of Pensacola  A flight training centre  Aviation depot  Rework facility  Industrial wastewater treatment  Aim – Protect Pensacola Bay from contaminant

4. Contaminated Area  Area affected by leakage Dry sludge bed Surge pond Ground water Underlying soil

5. Contaminants Chlorinated and non chlorinated solvents Trichloroethene (TCE) Dichlorateethene (DCE) Dichlorateethane (DCA) Vinyl chloride (VC) Ammonia Heavy metals Paints Plating wastes PCBs

6. Geological Data  Medium sand and silt at top 2 m  Medium-fine quartz sand between 2 – 40m  Water table 4~6m  Low chemically reactive  Little ability to absorb contaminant

7. Remedial Action Operation 1 st Pump and Treat (P&T) 1987 - 1998  Soil removal for Sludge bed Surge pond  Dewater contaminant soil  Disposed as a listed waste  Area cover with low permeability material  Water extraction Treated at waste water treatment plant

8. Remedial Action Operation 1 st Pump and Treat (P&T) 1987 - 1998 Waste Water Treatment Plant Groundwater Contaminant

9. Remedial Action Operation 2 nd Natural Attenuation Process 1996  Micro organisms degrade organic substances for nutrition and energy  Hazardous less toxic or non-toxic  Both aerobic and anaerobic biodegradation of contaminants occurs CH 4 + 20 2 C0 2 + 2H 2 0

10. Remedial Action Operation 2 nd Natural Attenuation Process 1996  Reduce in Trichloroethene (TCE) Vinyl chloride (VC), Dichloroethene (DCE), Dichloroethane (DCA), Biodegradation product  Shout down P & T system for further natural attenuation assess

11. Remedial Action Operation 3 rd In Situ Chemical Oxidation 1998 - 99  Fenton’s Reagent Method  Install carbon steel injectors  Injection concentrated hydrogen peroxide ferrous iron catalyst  Hydroxyl radicals reaction powerful, effective and no special oxidizing agent

12. Remedial Action Operation 3 rd In Situ Chemical Oxidation 1998 - 99  Small scale In Situ Chemical Oxidation Remediation Injector

13. Remedial Action Operation 3 rd In Situ Chemical Oxidation 1998 - 99  Reduce organic contaminant chlorinated compounds in groundwater  Non toxic by product water, carbon dioxide, hydrogen and chloride ions RHX Fe2+ + H 2 O 2 H 2 O + CO 2 + H + + X -

14. Remedial Action Operation 3 rd In Situ Chemical Oxidation 1998 - 99  Phase 1 November 1998 4,089 gallons of injection Reduced 81% chlorinated volatile organic compound (CVOCs)  Phase 2 May 1999 6,038 gallons of injection Reduced 97% of CVOCs

15. Conclusion  In Situ Oxidation Process Efficient for reducing CVOCs in a short period of time  Natural Attenuation Process Remediate remaining contaminant Require a reasonable period of time It eliminated P&T and reduced the cost on  long term remedial operation  monitoring

16. The End