Wastewater is discharged into an aquifer. This wastewater contains 0.1 ppm atrazine (a common herbicide). The MCL of atrazine is 5 ppb, the density is 1.19 g/mL and the solubility is 50 ppm. 500 ft away from the plant effluent there is a permeable reactive barrier filled with activated carbon. The aquifer has a hydraulic conductivity of 100 gpd/sf, an area of 50 sf, porosity of 0.4 and a hydraulic gradient of 0.003.
a. What is the discharge through the aquifer?
b. How long does it take for the wastewater effluent to reach the barrier?
c. How much atrazine must be removed per day to comply with the MCL regulation?