“GAS MART” petroleum facility in Florida By: Ernest Twum-Barimah Zhengzhong Fang (John) Zhengzhong Fang (John)

Introduction Geographical Context Located in the southern part of Florida Located in the southern part of Florida

Introduction History 1988: discharge of gasoline from underground storage tanks. 1988: discharge of gasoline from underground storage tanks. Contamination private drinking water wells near site up to a distance of a quarter mile. Contamination private drinking water wells near site up to a distance of a quarter mile.

INTRODUCTION Monitoring of well by Department of Health (DOH) started in same year Monitoring of well by Department of Health (DOH) started in same year Identification of up to 30 petroleum contaminated wells Identification of up to 30 petroleum contaminated wells Submission of discharge notification form for clean up Submission of discharge notification form for clean up 1999; completion of clean up, approved by department of environmental protection. (DEP) 1999; completion of clean up, approved by department of environmental protection. (DEP)

Problems Shallow aquifer in the area Shallow aquifer in the area Contamination of aquifer; lack of confining layers in area Contamination of aquifer; lack of confining layers in area Development of petroleum plume in ground water Development of petroleum plume in ground water Ground water leaching toxic chemicals such as benzene Ground water leaching toxic chemicals such as benzene Benzene in ground water > Hydrocarbons; both constituent of gasoline Benzene in ground water > Hydrocarbons; both constituent of gasoline Wells exceeded maximum contaminate level (MCL) for benzene Wells exceeded maximum contaminate level (MCL) for benzene

Causes of Problem Leakage of underground storage tanks (USTs) Leakage of underground storage tanks (USTs) Spillage of petroleum products on the ground Spillage of petroleum products on the ground Lack of tank maintenance Lack of tank maintenance No leakage monitoring device installed for USTs No leakage monitoring device installed for USTs No interlayer installed for USTs No interlayer installed for USTs Poor management Poor management

REMEDIATION Well Survey Well Survey Granular activated carbon (GAC) filters used to remove contaminants Wells are sampled, those with high level of benzene are connected to city drinking water Bioremediation Bioremediation microbial degradation restrict movement of contaminant plume & reduce concentration

REMEDIATION Natural Attenuation & Biodegradation Natural Attenuation & Biodegradation Used to reduce the concentration of contaminant in ground water Removal of leaking underground storage tanks Removal of leaking underground storage tanks Pump and treat Pump and treat ground water pumped and purified through series of vessels ground water pumped and purified through series of vessels Vessels have materials that absorb contaminant from ground water

REMEDIATION ALTERNATIVES Air stripping (ventilating) Air stripping (ventilating) Removal of volatiles compound such as BTEX compound in gasoline. Removal of volatiles compound such as BTEX compound in gasoline. Vacuuming at top: After 250 hours continuous vacuuming, over about 89% of the hydrocarbon from the gasoline can be removed. Vacuuming at top: After 250 hours continuous vacuuming, over about 89% of the hydrocarbon from the gasoline can be removed. Gas injection to the bottom: Based on same condition, 100 hours operating can remove approximately 80% of the hydrocarbon. But this method is not as efficient as the vacuuming. Gas injection to the bottom: Based on same condition, 100 hours operating can remove approximately 80% of the hydrocarbon. But this method is not as efficient as the vacuuming.

REMEDIATION ALTERNATIVES Remediation by chemical oxidation Remediation by chemical oxidation Injection of gasses into ground water to remove contaminant

Conclusion The DOH managed to clean the ground water, however there were still contaminants in the soil. The alternative ventilation methods could solve these problems. The DOH managed to clean the ground water, however there were still contaminants in the soil. The alternative ventilation methods could solve these problems. The DOH has a developed a contamination tracking system to monitor all the wells in area for future purposes The DOH has a developed a contamination tracking system to monitor all the wells in area for future purposes