Gasoline Spill Cleanup (Volatile Components) Rose Adam Allison Rose Adam Allison

Problem Statement  To Design a System for Removing Harmful Petroleum Contaminants from a Spill at a Large Fuel Distribution Facility in Central Minnesota

Methods  Determine Biodegradation for Natural Conditions  Vapor Extraction System Design to remove volatile components from Soil  Bio-filter to Breakdown Contaminants in Air  Determine Biodegradation for Natural Conditions  Vapor Extraction System Design to remove volatile components from Soil  Bio-filter to Breakdown Contaminants in Air

Natural Attenuation through Biodegradation  Benzene Breakdown in Natural Conditions  µ = days^-1 -First Order Reaction Coefficient of Benzene -Reaction Pathways:  Benzene Breakdown in Natural Conditions  µ = days^-1 -First Order Reaction Coefficient of Benzene -Reaction Pathways:

Natural Attenuation through Diffusion  Diffusion of Benzene chiefly through air pores in soil  Partition coefficients of other diffusion possibilities unfavorable  Diffusion of Benzene chiefly through air pores in soil  Partition coefficients of other diffusion possibilities unfavorable Diffusion through a porous media (gasoline through soil) using C/C++ Applications

Total Natural Attenuation Or analytically

Time for Natural Attenuation

Soil Vapor Extraction  Separates Contaminants from the Soil  Air Injection Extraction Wells Increase System Airflow  Vacuum Applied to Underground Wells To Remove Volatiles as Gas or Vapor  Separates Contaminants from the Soil  Air Injection Extraction Wells Increase System Airflow  Vacuum Applied to Underground Wells To Remove Volatiles as Gas or Vapor Typical System Schematic:

Diffusion Coefficient in Moist Sand Determining Concentrations:

Ground-Water Pump  Ground Water Located 4 ft Below Soil Surface  A sump Pump will be Utilized to Lower the Groundwater Level  Remove as much of the pure gasoline as possible  Ground Water Located 4 ft Below Soil Surface  A sump Pump will be Utilized to Lower the Groundwater Level  Remove as much of the pure gasoline as possible

Typical SVE Flow System

Or analytically Forced Attenuation

Time for Forced Attenuation

 Flow Rate: 76607m^3/day  The system will replace the air filled porosity 1.2 times per day  Assume ROI ~ 1000 m^2/well  15 Wells Required  Flow Rate: 76607m^3/day  The system will replace the air filled porosity 1.2 times per day  Assume ROI ~ 1000 m^2/well  15 Wells Required

Number of Extraction Wells Required The team has determined that 15 wells will be required for the SVE cleanup system

Air-Forcing Pump  Centurion II CP-HRV5-6 Specifications: * 5 Horsepower, Heavy Duty 1800RPM Motor * Champion Splash Lubricated RV15A Pump * Pump RPM 760 * Delivers 175PSI or 125PSI * Centrifugal Unloader for Loadless Starts * Dimensions: L=51 1/2, W=22 3/4, H=47 1/4  With a total required turnover of m^3 daily with 100 wells, 18.7 cfm is the minimum pump capacity.

Biofilter  Vapors extracted by the SVE process are typically treated using carbon adsorption, incineration, catalytic oxidation, or condensation. Other methods, such as biological treatment and ultraviolet oxidation, also have been used with SVE systems. The type of treatment chosen depends on which contaminants are present and their concentrations.

Governing Transport Equation Or analytically:

Bio-filter Pump  ratory/air_accessories/air_pu mps/index.shtml ratory/air_accessories/air_pu mps/index.shtml  Image and cfm data  Electricity draw data  Operating Cost: $0.068 / kw-hr  ratory/air_accessories/air_pu mps/index.shtml ratory/air_accessories/air_pu mps/index.shtml  Image and cfm data  Electricity draw data  Operating Cost: $0.068 / kw-hr

Design Specifications  Number of Extraction Wells  Biofilter  Number of Extraction Wells  Biofilter

Safety

Social Considerations  Drinking Water MCL  EPA Limit is 1ppb  EPA suggestion is 0 ppb  Beneficial to operate pumps longer than 6mo. if funds sufficient to lower concentration further.  Drinking Water MCL  EPA Limit is 1ppb  EPA suggestion is 0 ppb  Beneficial to operate pumps longer than 6mo. if funds sufficient to lower concentration further.

Cost Analysis  Energy cost of water pump  Pump Operating Cost ( at $0.068/kw-hr ) $109,  Energy cost of air pump  Capital cost of $1,538*100  Capital cost of well drilling  Energy cost of water pump  Pump Operating Cost ( at $0.068/kw-hr ) $109,  Energy cost of air pump  Capital cost of $1,538*100  Capital cost of well drilling

Questions