TM 5-814-3/AFM 88-11, Volume III
6-7. Package treatment plants.
Complete package treatment plants can be obtained from various manufacturers. The systems are usually
based on biological treatment such as extended aeration, contact stabilization, and activated biological filters.
These systems are capable of handling population equivalents of 10 to more than 1,000, but will be
considered only for flows of 0.1 million gallons per day or less. For designs beyond this range, request for
waiver will be forwarded to HQDA (CEEC-EB) WASH DC 20314-1000 for Army projects and HQ
USAF/LEEE WASH DC 20332 for Air Force projects, with complete documentation and information to
support the requested waiver. Some prefabricated plants may be relocated, depending on size and original
construction. Most of these units are factory fabricated and shipped as complete units, ready for connections
to piping and power. Small physico-chemical units have been developed as "add on" units to existing facilities
to provide additional treatment efficiency. Physico-chemical systems also have the flexibility to operate in an
on-off" mode which is not possible with biological systems. However, they are often costly to operate,
require skilled attention, and produce large amounts of sludge. See the Michigan State University studies of
natural ecosystems for further information on land application of wastewater.