MIL-HDBK-1005/16
f) Solids Production and Buildup. Estimate
production based on settleable solids removed plus biological
solids yield from BOD removal. For domestic sewage, use 1.2 lb
suspended solids produced per pound of BOD applied (1.2 kg
suspended solids produced per kg of BOD applied). Estimate solids
buildup in the final settling lagoon for storage and dredging
period determination based on 50 percent destruction of volatile
solids in anaerobic decomposition, and an accumulated solids
concentration of 10 percent. Provide a means for periodic
removal unless the solids storage volume is adequate for the
useful life of the lagoon.
7.4.2
Layout. See Figure 23 for alternative layouts with
multiple lagoons in series and parallel operation.
7.4.3
Construction. To prevent leakage, construct aerated
lagoons with earth embankments and impervious synthetic liners or
natural soil layers. See Figure 22 for details about aerated
lagoons. Refer to par. 7.7 for a discussion of liner and sealing
requirements.
7.4.4
Dimensions.
The following dimensions are minimum
values:
a)
Length-to-width ratio:
From 1:1 to 4:1
b)
Depth:
From 10 to 20 feet (3 to 6 m) (with mixing
provision)
c)
Freeboard: 3 feet (0.9 m)
7.4.5
Inlets and Outlets. Locate the inlet at maximum
distance from the outlet; discharge near aeration devices so
diffusion will be rapid. Provide for submerged drawoff to avoid
floating material in effluent.
7.4.6
Protection. Provide scour pads beneath mechanical
aerators to avoid any possibility of membrane liners being pulled
into aerator rotors. Provide splash blocks at inlet discharges.
Riprap banks at water surface.
7.5
Aerobic Lagoon Design. The aerobic lagoon is most
applicable to domestic waste treatment in subtropical and
tropical climates.
It should be considered for installations
with suitable land area and climate because it is simple to
operate and has low capital and operating costs. Aerobic lagoons
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