SEPTIC SYSTEMS

STANDARD:
This is the good old fashioned septic system, with the septic tank settling out the
solids & providing anaerobic treatment. The clarified liquids flow out by gravity to a
distribution box that evenly distributes the effluent to each drain field line. Most
drain fields currently are constructed with "gravel less chambers." These are
open-bottom plastic pipe-like chambers, which allow the lateral movement of the
effluent across the trench bottom. They are proven slightly more cost-efficient and
seem to treat the sewage slightly better. For standard system approval, typically four
(4) feed of good, dry soil is necessary with no seasonal water table.

PRESSURE DISTRIBUTION:
These systems are similar to standards with the exception of the method
of distribution. A pump chamber pumps the effluent (typically twice a
day) to the drain field, which has small diameter PVC lateral pipes within
it. These laterals have 3/16" orifices (holes) approximately every 6 feet.
When the pump comes on, each orifice squirts an equal amount of sewage
to its portion of the drain field. For pressure system approval, typically
three (3) feet of good, dry soil is necessary with no seasonal water table.

SAND FILTER:
These systems have disposal drain fields identical to pressure
distributions, but also provide additional treatment between the tanks
and drain field. Sand filters are essentially a lined box under the ground.
Effluent is pumped into the top gravel layer (9 inches thick) for dispersal
over the sand layer. The sand layer (24 inches thick) provides a place to
live and work for the bacteria that consume the bad parts of sewage. By
the time the sewage makes its way through all the sand, over 90% of the
sewage strength is reduced. Then the cleaner sewage is ready to dispose
into the pressure distribution drain field. For sand filter system approval,
typically two (2) feet of good, dry soil is necessary with no seasonal
water table.

SAND MOUND / GLENDON:
These systems are above-ground systems for sites with less than 24 inches
of available treatment soil. The primary treatment is with sand media.
With mounds, the treatment is by gravity (see sand filter) through the
sand, and goes directly from there to the soil. With Glendons, the
treatment is by capillary action (upward flow) within a treatment basin,
and then it flows over the sides through the sand into the soil. While
necessary on wetter sites, both of these types are less popular due to their
poor aesthetic qualities.