aerobic treatment units
Aerobic treatment units (ATUs) provide
aerobic biological decomposition of wastewater constituents
by mechanically bringing the wastewater in contact with
air. ATUs come in different configurations and sizes,
and incorporate a variety of approaches, including air
pumps, air injectors, lift pumps and biological-contact
surfaces (such as pipes, fabric, grids, gravels, and
rotating disks). Other alternative wastewater treatment
technologies, such as sand filter systems, may also
be described by this characterization, however they
are not categorized by the Washington State Department
of Health (DOH) as aerobic treatment units or systems.
ATUs are not stand-alone wastewater
treatment systems, but provide wastewater treatment
prior to disposal in a subsurface drainfield system
or provide pre-treatment to other alternative methods
of wastewater treatment and/or disposal
This technology is used on sites
with shallow soil conditions where treatment must be
accomplished before disposal. ATU effluent may be discharged
to as little as 12 inches of vertical separation.
To view the
complete Recommended
Standards and Guidance for Performance, Application,
Design, and Operation and Maintenance of the Aerobic
Treatment Unit you may follow the following links:
Aerobic
Treatment Units
(Effective Date: December 31, 2003) - in Adobe Acrobat
Format.
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