GROUNDWATER - Water Quality Engineering in Natural Systems - page 201

20°C, calculate the rate at which the blower
will remove air from the vadose zone.
(b) If the extraction well is placed such that 50%
of the pumped air flows through the contami-
nated zone, approximately how long will it
take to remediate the soil?

extraction wells be located 70 m downstream of
the plume. The aquifer has an estimated hydraulic
conductivity of 30 m/d, and the regional flow is
along the plume axis with a water table slope of
0.05%. (a) Determine the required pumping rate
using one extraction well, and (b) determine the
extraction rate using two extraction wells spaced
5 m apart.

5.41. A contaminant plume 50 m long and 10 m wide is
to be removed using a pump-and-treat system. The
aquifer has a saturated thickness of 25 m and a
regional specific discharge of 0.5 m/day. If the
extraction wells can be placed a maximum of 200 m
downstream of the center of the plume, and the
maximum allowable pumping rate is 650 L/min
from each well, determine the required number,
location, and discharge rate of the extraction wells.

5.43. A contaminant plume 50 m long and 60 m wide is
to be remediated using a pump-and-treat system
that can handle 100 L/min. The pumping and
injection wells are to be placed in a doublet
arrangement to prevent further migration of the
plume in the aquifer. The regional hydraulic
gradient is 0.15%, the average hydraulic con-
ductivity is 15 m/day, and the saturated thickness
of the aquifer is 25 m. What well spacing between
the pumping and injection wells would you
recommend?

5.42. A plume of contaminated groundwater is 120 m
long and 60 m wide, and penetrates the entire
aquifer depth of 20 m. Site constraints require that