TM 5-814-3/AFM 88-11, Volume III
16-7. Sludge storage.
a. Sludge tanks. Sludge storage tanks may have depths no less than 15 feet and bottom slopes of 1 in
4. The tanks may be open or closed. Ventilation must be provided with closed tanks. Decanting lines as well
as sludge withdrawal lines must be provided for all tanks.
b. Sludge retention ponds. Sludge retention facilities will be provided at either the treatment plant or
land application site. The design detention period will be large enough to compensate for periods when sludge
spreading is not feasible but will not be less than 30 days. Storage will permit operation flexibility, additional
destruction of pathogens and further sludge stabilization.
c. Sludge storage ponds. Sludge storage ponds are applicable for storage of well-digested sludge when
land area is available. Storage is usually long term (2 to 3 years), with moisture content being reduced to 50-
60 percent. Lagoon storage can be used as a continuous operation or can be confined to peak load situations,
and serves as a simple and economical sludge storage technique. Land requirements and possible groundwater
pollution are the major disadvantages. (See Bitton et al., 1980; Bower et al., 1974; Eikum, 1982.)