““GAS MART”GAS MART”petroleum facility in Floridapetroleum facility in Florida

By: Ernest Twum-Barimah By: Ernest Twum-Barimah

Zhengzhong Fang (John)Zhengzhong Fang (John)

IntroductionIntroduction

Geographical ContextGeographical Context Located in the southern part of FloridaLocated in the southern part of Florida

IntroductionIntroductionHistoryHistory

1988: discharge 1988: discharge of gasoline from of gasoline from underground underground storage tanks.storage tanks.

Contamination Contamination private drinking private drinking water wells water wells near site up to near site up to a distance of a distance of a a quarter mile.quarter mile.

INTRODUCTIONINTRODUCTION

Monitoring of well by Department of Health Monitoring of well by Department of Health (DOH) started in same year(DOH) started in same year

Identification of up to 30 petroleum contaminated Identification of up to 30 petroleum contaminated wellswells

Submission of discharge notification form for Submission of discharge notification form for

clean upclean up 1999; completion of clean up, approved by 1999; completion of clean up, approved by

department of environmental protection. department of environmental protection. (DEP)(DEP)

ProblemsProblems Shallow aquifer in the area Shallow aquifer in the area Contamination of aquifer; lack of confining layers Contamination of aquifer; lack of confining layers

in areain area Development of petroleum plume in ground Development of petroleum plume in ground

waterwater Ground water leaching toxic chemicals such as Ground water leaching toxic chemicals such as

benzenebenzene Benzene in ground water > Hydrocarbons; both Benzene in ground water > Hydrocarbons; both

constituent of gasolineconstituent of gasoline Wells exceeded maximum contaminate level Wells exceeded maximum contaminate level

(MCL) for benzene(MCL) for benzene

Causes of ProblemCauses of Problem

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

REMEDIATIONREMEDIATION

Well SurveyWell SurveyGranular activated carbon (GAC) filters used Granular activated carbon (GAC) filters used

to remove contaminantsto remove contaminants

Wells are sampled, those with high level of Wells are sampled, those with high level of benzene are connected to city drinking benzene are connected to city drinking waterwater

BioremediationBioremediation

microbial degradation restrict movement of microbial degradation restrict movement of contaminant plume & reduce concentrationcontaminant plume & reduce concentration

REMEDIATIONREMEDIATION

Natural Attenuation & BiodegradationNatural Attenuation & BiodegradationUsed to reduce the concentration of contaminant in Used to reduce the concentration of contaminant in

ground waterground water

Removal of leaking underground storage Removal of leaking underground storage tanks tanks

Pump and treatPump and treat ground water pumped and purified through ground water pumped and purified through

series of vesselsseries of vesselsVessels have materials that absorb contaminant Vessels have materials that absorb contaminant

from ground waterfrom ground water

REMEDIATION ALTERNATIVESREMEDIATION ALTERNATIVES

Air stripping (ventilating)Air stripping (ventilating)

Removal of volatiles compound such as BTEX Removal of volatiles compound such as BTEX compound in gasoline.compound in gasoline.

Vacuuming at top:Vacuuming at top: After 250 hours continuous vacuuming, After 250 hours continuous vacuuming, over about 89% of the hydrocarbon from the gasoline over about 89% of the hydrocarbon from the gasoline can be removed.can be removed.

Gas injection to the bottom:Gas injection to the bottom: Based on same condition, 100 Based on same condition, 100 hours operating can remove approximately 80% of the hours operating can remove approximately 80% of the hydrocarbon. But this method is not as efficient as the hydrocarbon. But this method is not as efficient as the vacuuming. vacuuming.

REMEDIATION ALTERNATIVESREMEDIATION ALTERNATIVES

Remediation by chemical oxidationRemediation by chemical oxidationInjection of gasses into ground water to remove Injection of gasses into ground water to remove

contaminantcontaminant

ConclusionConclusion

The DOH managed to clean the ground The DOH managed to clean the ground water, however there were still water, however there were still contaminants in the soil. The alternative contaminants in the soil. The alternative ventilation methods could solve these ventilation methods could solve these problems.problems.

The DOH has a developed a The DOH has a developed a contamination tracking system to monitor contamination tracking system to monitor all the wells in area for future purposesall the wells in area for future purposes