Size a bank of walnut-shell oleophilic-media filters for final polishing of produced water from 10–50 mg/L oil down to 2–10 mg/L. Walnut shell preferentially adsorbs oil over water; periodic backwash with product water restores capacity. Last stage before reuse, discharge, or low-spec SWD.
Process
BWPD
mg/L
mg/L
psig
Filter Bed
gpm/ft²
8–15 typical
in
+1 standby for backwash
Backwash
gpm/ft²
min
hr
📚 Theory
Oleophilic media chemistry, loading + bed-depth design, backwash optimization.