continuous loop reactor. Comply with TM 5-814-3 to
determine design criteria.
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Treatment of the wastewater shall be accomplished by contact with the waste
activated sludge in the CLR for a minimum of [18] [_____] hours. The CLR
shall be sized for an average daily flow of [_____] L per second mgd and a
peak daily flow of [_____] L per second mgd. The CLR shall remove a
minimum of [_____] percent of the influent five day BOD at the average
daily flow rate and influent five day BOD.
1.2.2
Mixing Parameters
The aeration/mixing system selected shall provide the propelling force for
circulation and mixing of the basin contents. The aeration/mixing unit(s)
shall be sized to maintain an average horizontal velocity of not less than
[0.305] [_____] m per second [1.0] [_____] fps throughout the basin and
maintain a uniform mixed liquor suspended solids (MLSS) concentration
throughout the basin at MLSS concentrations up to [5000] [_____] mg/L, with
one aeration/mixing device not operating.
1.2.3
Aeration Parameters
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NOTE: The Actual Oxygen Requirement (AOR) is
calculated by the designer. The oxygen required for
oxidation of BOD and the oxygen required for
nitrification must be included in the AOR. Typical
values are 0.82 kg (1.8 pounds) of oxygen per 0.45
kg (1.0 pound) of BOD applied and 2.1 kg (4.6
pounds) of oxygen per 0.45 kg (1.0 pound) of TKN
applied. The alpha coefficient is defined as the
ratio of the oxygen transfer in the wastewater to
the oxygen transfer in clean water and may vary from
0.2 to 1.5. The alpha coefficient is a direct
multiplier in determining oxygen transfer
capabilities and is affected by mixed liquor
temperature, liquid depth and basin geometry, the
level of turbulence, mixing patterns and the nature
of dissolved organics and mineral constituents in
the wastewater and even the type of aeration
equipment. Fine bubble aeration systems typically
have lower alpha values than mechanical aeration
systems. Because of this variation in alpha value a
default value is not shown below. The Beta
coefficient is defined as the ratio of oxygen
saturation level for the wastewater (mixed liquor)
to the oxygen saturation level for tap water. Theta
is a temperature correction coefficient for oxygen
transfer efficiency (OTE). Values of 1.020 to 1.028
are normally used for diffused air systems, while a
value of 1.024 is normally used for mechanical
aeration systems.
An OTE of 0.507 mg oxygen per joule (3.0 lb.
oxygen/hp-hr) under standard conditions is an
average value for aeration equipment commonly used
in closed loop reactor applications. Designer
should contact the aerator manufacturer for the OTE
SECTION 11391
Page 8
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