Remediation of Hydrocarbon Contaminated Soils at MCAGCC, Twentynine Palms, CA

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1 Remediation of Hydrocarbon Contaminated Soils at MCAGCC, Twentynine Palms, CA Al Pollack (Battelle Memorial Institute) Mike Ellitt & Leon Bowling (MCAGCC) George Reed (El Adobe Partners, Inc.)

2 Marine Corps Air Ground Combat Center Largest live-fire training facility in the Corps Combined Arms Exercises can be conducted on over 900 square miles of ranges Training requires aggressive use of ground and air support

3 Operational Issue: Soil Contamination Types of Soil Contaminants: Diesel Fuel Jet Fuel Oils/Lubricants Coolants Hydraulic Fluids Refueling Spills/Wash Rack Soils/Accidents Result in the Generation of ~2,000 to 3,000-yds 3 of Contaminated Soil per Year

4 What to do with this contaminated soil? Off-Site Disposal: Inventory and maintain stockpile Costs to haul soils to a permitted landfill Disposal costs at landfill Utilizes limited off-site landfill space On-Site Treatment and Land Use: With treatment, soils can be used for daily cover at Base s Subtitle D landfill Less expensive than off-site disposal Leaves regional landfill space for other materials

5 Cost-Effective Technological Solution Aerobic Bioremediation of Hydrocarbon Contamination via Biopile Operations Requirements: Soil storage and remediation facilities: capital expense Oxygen: atmospheric O 2 is free Appropriate soil moisture: ~20,000 gallons of water per 2,500 yd 3 biopile Naturally occurring microbial populations: free Target nutrient concentrations: C:N:P ratio of 100:15:1 Microbial food source: hydrocarbon contamination in soil

6 MCAGCC s Bioremediation Facility

7 Contaminated Soil Staging Area (CSSA) Provides a Place to: Reserve contaminated soils until treatment Prepare the soil before going to the biopile facility

8 Biopile Facility

9 Biopile Utility Pad

10 Permitting and Cleanup Goals Mojave Desert AQMD Operating Conditions: Pre-startup off-gas sampling, time integrated 8-hr whole-air off-gas sample < 25 lbs/day of TPH emissions, as hexane < lbs/day of BTEX emissions Monthly off-gas monitoring to confirm acceptable TPH emission limits Regional Water Quality Control Board Soil Cleanup Goals: < 1,000 mg/kg TPH < 1 µg/kg benzene < 50 mg/kg toluene, ethylbenzene, xylenes

11 Biopile Construction (1 of 4) Soil Preparation and Hauling

12 Biopile Construction (2 of 4) Assembly of Biopile

13 Biopile Construction (3 of 4) Surface Preparation

14 Biopile Construction (4 of 4) Completed Biopile

15 Final Preparations and Startup 1. Install soil-gas oxygen sensors and data logger 2. Install irrigation system 3. Conduct initial soil sampling/analysis 4. Perform off-gas sampling/analysis 5. Review data and submit letter report that supports request to start the biopile operation 6. When authorization is received, start the blowers

16 Biopile Monitoring and Sampling Monitor Oxygen Levels in the Soil Gas Uniform aeration of the soil Conduct respiration tests Soil Moisture Levels Monthly sampling and on-site analysis Sample Offgas for TPH Levels Monthly sampling with a portable FID Final Sampling 50 Sampling Locations: 1 per 50 yd 3 Statistical Analysis of Data

17 Daily Operations Just look and listen!

18 When is Remediation Done? When rates fall below 1 mg/kg/day, time to sample

19 Utilization of Remediated Soils Soil staged for use as cover at Base landfill

20 Biopile Facility Maintenance Soil gallery inspection and utility pad maintenance

21 Optimization and Cost Reductions Conducted treatability studies to determine optimal site-specific remediation conditions Confirmed oil/water separator and wash rack soils were suitable for biopile remediation Have reduced initial analytical costs by approximately 55% Reduce labor via automated respiration-rate testing with low-cost sensor array Currently verifying that coolants and hydraulic fluid contaminated soils are also suitable for biopile treatment

22 Cost Benefits Analysis On-Site Treatment Costs, ~$90K Analytical: ~$25K Materials: ~$5K Labor: startup, initial/monthly/final sampling, shut down, maintenance, technical oversight/data analyses, and reporting: ~$60K Off-Site Disposal Costs, per 2,500 yds 3, ~$168K Hauling Cost: ~$450/20 tons or $56K/biopile Disposal cost: ~$45/ton or $112K/biopile Other Costs: labor to stockpile, maintain records, arrange for disposal, analytical

23 Future Process Enhancements Request regulatory approval to treat coolant and hydraulic fluid contaminated soils Improve durability of blowers Wherever possible, continue to reduce analytical costs but still meet all regulatory requirements

24 Summary To date, 27,000 yds 3 of soil have been treated Can remediate ~5,000 yds 3 of soil per year On-site treatment costs are well below off-site disposal costs If the soil had been sent off-site for disposal, hauling/disposal costs would have been close to $2M and would have resulted in the unnecessary use of landfill space in Southern California

25 Acknowledgements Natural Resources and Environmental Affairs Directorate (NREA) at MCAGCC Major Milton Clausen El Adobe, Inc. Staff Earl Reed, Chad Fairweather, and Asami Beamer