MIL-HDBK-1005/16
depending on storage rather than blending requirements. Provide
mechanical mixing to ensure complete blending of the solids.
Because solids will go septic rapidly, the blend tank
should be aerated or provided with chlorine or hydrogen peroxide
feed to control odors. Covering tanks when the contents are
anaerobic may lead to severe sulfide-induced corrosion above the
liquid surface unless adequate ventilation is provided.
10.10
Storage. The rates of solids production and processing
at a wastewater treatment plant vary independently with time.
The rates of primary and secondary solids production vary with
the plant influent suspended solids and organic loadings, whereas
the rate of solids processing varies with the nature and capacity
of the processing and disposal system and the manner in which the
system is operated. In general, solids production is continuous,
while certain portions of the processing system are
discontinuous, e.g., 8 to 16 hours per day, 5 days per week.
Likewise, sometimes solids cannot be disposed during inclement
weather or during certain seasons of the year.
Consequently, solids storage capacity is mandated at
all mechanical wastewater treatment plants. Temporary storage
can be provided within settling basins. Longer-term storage can
be provided within digesters, separate blend/storage tanks, or
lagoons. If the solids have been stabilized and dewatered,
stockpiling on a pad may be acceptable. In humid climates,
dewatered cake stockpile areas should generally be covered.
The required solids storage volume should be calculated. Methods
of calculation are described in Metcalf & Eddy, 1991, and in
MOP 8.
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