Conventional Systems
Gravity
System — Basic or standard system, uses gravity to
move effluent through the septic tank and into the drainfield.
For more information, see
Gravity System.
Pressure Distribution System
— Has a pump which distributes effluent throughout the
drainfield at the same time. Used in most new systems because it
makes better use of the entire drainfield. See
Pressure Distribution System for additional information.
Alternative Systems
Aerobic Treatment Unit (ATU)
— Uses oxygen to break down solids, producing cleaner wastewater
than conventional types. Often used in environmentally sensitive
areas where effluent requires more treatment before entering the
drainfield. For additional information, see
Aerobic Treatment Units (ATUs).
Mound System — Installed
when minimal soil is available for treatment, drainfield is
raised above ground level. See
Mound System for more details.
Sand Filter System — Has a
sand filtering system and pump to treat and disburse effluent,
used when minimal soil is available for treatment. To find out
more, see
Sand Filter System .
Proprietary Systems
Glendon®
BioFilter — This alternative system consists of different layers
of sand and gravel placed in a watertight box. Sewage effluent
is pumped into the bottom of the filter and then works its way
up through the sand and out into the soil. For additional
information, see
Glendon BioFilters (WA Dept of Health
publication).
AdvanTex Filter — In this system, the effluent is filtered
through a bed of engineering textile material that is enclosed
in a watertight container. This allows treatment of a large
amount of wastewater in a small space and is clean enough for
subsurface irrigation.
Drip Irrigation — This is a shallow, pressure-dosed system that
equally distributes pretreated waste-water at a slow rate over the entire drain field, preventing
saturation of the soil.