MIL-HDBK-1005/16
settling pond for the aerated lagoon effluent is usually provided
to remove suspended solids. The aerated lagoon is operated as a
complete mix, mechanically stirred, with no recycle system.
Compared with activated sludge systems, aerated lagoons have low
capital and operating costs and greater ease of operation.
Therefore, aerated lagoons should be strongly considered for use
at installations where adequate land area is available and
discharge limits are not strict.
7.4.1
Sizing Basis
7.4.1.1
Number of Equally Sized Basins. Provide at least two
hydraulically separate and aerated basins and a third basin for
solid-liquid separation. Aerated basins should be designed to
operate either in series or in parallel flow pattern.
7.4.1.2
Design Conditions.
Use the more critical of the
following conditions:
a) Summer Conditions. Maximum BOD load for detention
period; design removal as required for receiving water; normal
summer wastewater temperatures; one basin out of service.
b) Winter Conditions. Same design load as summer;
minimum wastewater temperature; removal as required for receiving
water; all basins in service. Account for anticipated ice volume
in total volume.
7.4.1.3
Performance and Operating Requirements.
a) Detention time. Determine required total detention
time for a given number of complete mix ponds in series operation
using Equation 1. It can be assumed that dissolved effluent BOD
is 50 percent of total effluent BOD; that is, effluent TSS
contribute 50 percent of total BOD.
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