|Posted by Bud...Suncoast Plumbing Inc. on May 21, 1999 at 06:45:53:|
|In response to Re: septic system|
Debbie: A sand filter system is used generally where the lay of the land does not lend itself to the typical drain field installation. In some cases it is used if the ground percolation characteristics are less than suitable.
The key to its operation is in that a large hole is excavated 8'-10' deep and a open bottomed reinforced masonry box is constructed (like the basement and foundation for a small house, but without any floor.) This box typically extends 6 or 8 feet above grade and is filled with coarse builders sand. The liquid portion of the sanitary effluent from the septic tank is pumped to and discharged into distribution piping at the top of the sand filter. Gravity does the rest...as the effluent makes its way down through
the sand filter, it forces its way into the soil beneath the filter and out into the surrounding area. Beause of the altitude of the sand filter structure, and the inpermeability of the walls, the effluent develops a head pressure of several psi to drive the liquid discharge into the ground.
This type of system will work where a traditional drain field is not possible due to hilly terrain or "perk" problems, it can be a fairly expensive means to install however. Bud