The capacity of xylem filters depends on water quality, filter design, and use of pre-filtration.
With WHO-prescribed General Test Water (GTW) that represents high quality groundwater, xylem filters have a capacity of 6.07 ± 4.40 L/cm2 when operated under a 1 meter pressure head. Xylem filters made from ginkgo with 4 cm diameter and ~1 cm thickness could process 34-84 L of GTW under 1 meter gravity.
Xylem filters are most susceptible to fouling by large organic molecules like humic acid and dust. With WHO-prescribed Challenge Test Water (CTW) having aggressive specifications and high concentrations of humic acid and dust, xylem filters have a capacity of 0.58 ± 0.47 L/cm2. Xylem filters made from ginkgo with 4 cm diameter and ~1 cm thickness could process 6-12 L of CTW under 1 meter gravity. Filter capacity with CTW can be improved by using simple, inexpensive pre-filtration methods. For example, cloth and granular activated carbon (GAC) could be used for reducing the load of dust and humic acid, respectively. With cloth and GAC pre-filtration, xylem filters with 4 cm diameter and ~1 cm thickness can process 26-31 L when operated under a 1 meter gravity head.