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.
Describe what you would do first to recover the NAPL. What
will limit how much you expect to recover?
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
Your proposed cleanup plan includes enhanced in situ biodegradation.
What environmental factor is probably limiting the present
biodegradation rate most?
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)
i. A solution
containing 250g/liter of H2O2, which decomposes to O and
equilibrated with air at one atmosphere?
equilibrated with 1atm of O2?
containing KNO3 at its solubility limit (2.1M at 10oC)?