MIL-HDBK-1138
the potential for scum accumulation in the downstream processes.
Other general considerations when adding septage to the liquid
stream include the following:
a) Slug loads versus continuous discharge of septage.
The allowable loadings should be reduced by nearly one-half for
slug loadings. Estimating allowable loadings is discussed in
par. 6.4.1. Because of shock organic loadings and other
undesirable process impacts, slug loads are not recommended.
b) Timing of discharge. If the available primary
treatment and secondary treatment capacities are limited, the
septage could be metered into the plant during off-peak demands.
c) Ultimate disposal from the treatment facility. The
permit limitations or other requirements for disposing of the
treatment plant effluent and biosolids need to be considered when
accepting septage. The organic and inorganic constituents of the
septage may affect the effluent and biosolids quality, including
concentrations of BOD, TSS, nitrogen, phosphorus, and heavy
metals.
d) Scum accumulation in the clarifiers. The scum
handling equipment for the primary and secondary clarifiers
should have the capacity to handle the increased loadings of oil,
grease, and floatables.
e) Increased sludge volumes. The volume of primary
and waste activated sludges will increase. Therefore, the
processes and equipment used for handling the sludge should have
the capacity to accommodate the increased sludge quantities.
f) Location of septage addition to a trickling filter
plant. Septage should be discharged upstream of primary
clarifiers if trickling filters are used for secondary treatment.
This will minimize the potential for filter media fouling.
Co-Treatment of Septage in Solids Stream. The
6.4.3
screened and degritted septage can be mixed and treated with
primary and secondary treatment plant sludges. Adding septage to
the solids stream nearly eliminates any adverse effects on the
liquid treatment processes and equipment. The undesirable
constituents of septage are kept out of the major flowstreams of
the plant, thereby requiring less operation and maintenance.
Depending on the ultimate disposal method,
stabilization is normally required prior to disposal. The
septage can be treated using either aerobic or anaerobic
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