2. Methods and materials
2.1. Laboratory Fe0 column experiments
Laboratory column test experiments were conducted
with a native groundwater (Tempe, AZ) spiked with
nitrate at a rehabilitated wellsite. Table 1 summarizes
the average water quality conditions for the native
groundwater. Water quality was typical of regional
wells, characterized by DO concentrations of 4–6 mg/L.
The well serves as a hydrologic linkage between two
different aquifer units. Localized pumping affected
water levels in the aquifer units, which have different
nitrate levels. Hence, during testing, localized pumping
affected influent nitrate levels and water quality.
Lab column tests were conducted using plexi-glass
columns (600mL; 5 cm diameter; 30 cm height). The Fe0
columns were packed in 2–5 cm lifts by adding preweighed
dry Fe0 (1636 g at 6.32 g/cc of FE5; 2271 g at
7.89 g/cc of FE7) to distilled water. A lower support
layer of 3 cm of clean sand was packed in the column
first, and 2 cm was placed above the Fe0 material. The
final column porosity was approximately 40%. Previous
batch experiments screened several types of Fe0 for
nitrate removal capability [18], and two iron types were