Chemistry III
You are called to consult on a LUST problem; an estimated 2000kg of gasoline was lost from a local service station before the leak was discovered. A layer of gasoline now floats on the water table 7m below ground surface. A detailed examination of records suggests that the leak began 2 years ago.
a) Describe what you would do first to recover the NAPL. What will limit how much you expect to recover?
b) Some of the gasoline has dissolved in water and migrated downgradient. Specific discharge associated with natural groundwater flow under the station is 20m/year. It is 25m downgradient from the edge of the bolus of gasoline to the property line. Do you think the gasoline is contained on the property? Aquifer material is a silty fine sand with 0.5% organic carbon. Assume gasoline has an effective log Koc of two (it is actually a mix of compounds, each having its own Koc) and make other reasonable and necessary assumptions.
c) Your proposed cleanup plan includes enhanced in situ biodegradation.
a. What environmental factor is probably limiting the present biodegradation rate most?
b. You are contemplating the addition of water containing mineral nutrients and electron acceptors. You naturally want as many equivalents of oxidizing capacity as possible in each liter of water that you inject. If you assume a temperature of, what is the capacity (in equivalents/liter) of
i. A solution containing 250g/liter of H2O2, which decomposes to O and H2O?
ii. Water equilibrated with air at one atmosphere?
iii. Water equilibrated with 1atm of O2?
iv. Water containing KNO3 at its solubility limit (2.1M at 10oC)?