Mercury Impacted Soil Cleanup at a Natural Gas Processing Facility Gilbert J. Van Deventer, REM Trident Environmental PO Box 7624 Midland, Texas

Project Elements l Disposition of 32 mercury manometer gas flow meters stored in the crawl space of an office at a natural gas processing facility in east Texas l Characterization of mercury-impacted soil in crawl space floor l Remediation of mercury-impacted soil in crawl space

Safety Concerns l Mercury vapors inside crawl space exceed permissible exposure limits (PELs) l Confined space entry procedures must be followed l Level B personal protective equipment (PPE) required l Jerome Model 431X mercury vapor analyzer (MVA) used for monitoring

Vapor Exposure Limits for Mercury

Disposition of 32 mercury manometer gas flow meters l Meters were removed from crawl space l Meter components were disassembled l Mercury bearing components placed in 55-gal. steel drums l Meters were shipped to a permitted facility for recycling

Characterization of Mercury Impacted Soil in Crawl Space l Sample grid pattern established in crawl space based on 5- foot centers (same as steel piers supporting office building) l Composite samples from each grid cell collected were screened with an MVA and submitted to the laboratory for total mercury analysis (EPA Method 7471)

Sampling Grid Pattern

Remediation of Mercury Impacted Soil in Crawl Space l Phase 1: Soil removed using hand shovels l Phase 2: Remaining loose soil removed using industrial vacuum l Phase 3: Merconwash TM (1.5 liters ) mercury vapor suppressant and decontamination liquid applied to floor of crawl space l Phase 4: Merconwash TM (10 liters ) mercury vapor suppressant and decontamination liquid applied to floor of crawl space 8 months after initial remediation activities

MVA Readings Prior to Implementation of Remediation

MVA Readings During Implementation of Remediation

MVA Readings After Completion of Remediation

Total Mercury Concentrations After Completion of Remediation

MVA Readings After Application of 10 liters of Merconwash

Summary of MVA Readings

MVA Readings in Office Above Crawl Space