MIL-HDBK-1005/16
c) Inlet and Outlet.
Refer to par. 7.3.4 for
rectangular ponds.
d)
Construction.
Refer to pars. 7.3.5 and 7.4.3.
e) Layout. Use multiple rectangular lagoons in series
or parallel operation with length-to-width ratios of 2:1 to 3:1.
The individual lagoon area should be less than 10 acres (4 ha) to
minimize short-circuiting caused by wind action. Recirculation
may be used to increase oxygenation capacity and seed influent
sewage with algae cells. Recirculation ratios are 0.2 to 2.0 and
average 0.5. See Figure 23 for alternative lagoon flow
schematics.
f) Performance. Performance criteria for aerobic
lagoons are similar to those for facultative lagoons except algae
concentrations are higher (100 to 200 mg/L for aerobic lagoons).
Aerobic lagoons should be preceded by primary treatment for
removal of settleable organic solids. If the system is not
preceded by primary treatment, influent nondegradable solids will
gradually fill the lagoon.
7.6
Anaerobic Lagoon Design. Anaerobic lagoons are deep
lagoons that receive high-strength biodegradable organic wastes
such that anaerobic conditions prevail throughout the lagoon
depth. This lagoon type is used primarily to pretreat industrial
wastes and is generally not applicable to wastewaters generated
at military facilities. For design guidance, see
EPA-625/1-83-015.
7.7
Lagoon Sealing. Lagoons are sealed to minimize seepage
and the resulting adverse effect on groundwater quality and
treatment performance. Pond sealers are classified into three
categories: synthetic and rubber liners, earthen and cement
liners, and natural and chemical treatment sealers. Natural
sealing occurs because soil pores become physically clogged by
settled solids, pores become chemically clogged by ion exchange
and precipitation, and pores become biologically clogged by
microbial growth. Natural sealing depends on wastewater
characteristics and should not be relied on for satisfying design
seepage criteria. Chemical treatment sealers change the nature
of the bottom soil.
Contact the state regulatory agency for design seepage
rate and groundwater monitoring requirements at the lagoon site.
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