Evaluation of Septic Tank and Subsurface Wetland for

Figure 4-3 Media porosity measurement using a 5-gallon bucket at Pisgah.
(Photograph by author.)
Media porosity was measured by filling a bucket with rocks and measuring the quantity
of water required to fill the voids to the confirmed 5-gallon mark (see Figure 4-3). This
did not take into account any changes resulting from root growth which in one study was
estimated to fill 2.5 – 7.9% of the void volume (George et al., 2000).
One alkalinity sample was collected for each source and tested at NWC. Septic tank
sludge depth was measured at the end of the evaluation using dip sticks with white cloth
wrapped around the end (see Figure 4-4). Since the sandy sludge did not want to stick to
the white cloth, the depth was estimated by sensing when the tip of the dip-stick touched
the top of the sludge mound.
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