13    TREATMENT OF COMBINED MUNICIPAL/PACKING
HOUSE WASTEWATER USING AN INNOVATIVE
CONTINUOUSLY FED-INTERMITTENTLY OPERATED
ACTIVATED SLUDGE PROCESS: A DESIGN
RATIONALE
Kevin S. Young, Vice-President
J. R. Wauford & Company
Consulting Engineers, Inc.
Jackson, Tennessee 38305
INTRODUCTION
This paper presents the procedure and the rationale behind the procedure used to design a
continuously —fed, intermittently aerated, settled and discharged activated sludge facility to treat a
combined municipal and packing house wastewater. Technical criteria for process selection included:
1) Capability to hydraulically accommodate peak/base flow ratios of up to 9:1; 2) Capability to
consistently meet year-round secondary effluent standards summarized in Table I with seasonal
winter/summer ratios for influent organic and hydraulic loadings of 1.35:1 and 1.50:1, respectively;
and 3) Capability to accommodate slug loadings of relatively inert suspended solids.
Preliminary evaluations of one conventional and two innovative biological treatment processes
were conducted in early 1983. Comparisons of the conventional oxidation ditch, interchannel clarifier
variation of the oxidation ditch and the continuously-fed, intermittently operated activated sludge
system were made based on process performance capabilities, capital costs and life cycle costs. Neither
the interchannel clarifier variation of the oxidation ditch nor the continuously-fed, intermittently-
operated, activated sludge system had been operated on a full-scale basis in this country in early 1983.
These two innovative processes were evaluated using foreign full scale and domestic pilot plant data.
The comparison of these three technologies indicated that the continuously-fed, intermittently-
operated, activated sludge system could meet all of the technical criteria for process selection and
could provide the lowest life cycle cost.
WASTEWATER CHARACTERIZATION
The 1980 U.S. Census reported Union City's population as 10,436. With the exception of the
packing house, Union City has a broad base of clean industry. The packing house kills and processes
approximately 700 cattle and 3,000 hogs per day. Pretreatment is provided prior to discharge into the
municipal sewer system by a grease removal unit and a 4.5 acre anaerobic lagoon with an average
depth of nine feet. Discharge from the anaerobic lagoon is monitored by the City for flow, BOD5 and
suspended solids three times per week.
Analysis of a temporal plot of several year's daily flow, BOD5, and suspended solids data for the
combined municipal/packing house waste stream indicated a distinct difference in values of these
wastewater parameters between winter and summer. Statistical plots of values of each parameter for
the individual domestic waste stream and packing house waste stream for .the periods May through
November and December through April indicated distinct seasonal differences in flow and organic
and suspended solids loadings. Median values for existing flow and organic and suspended solids
loadings are summarized in Table II.
Table I. Effluent Standards (Union City, Tennessee)
BOD, 30 mg/L
Suspended Solids 30 mg/L
Ammonia Nitrogen 15 mg/L
Dissolved Oxygen 1.0 mg/L
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