43    DEWATERING DISSOLVED-AIR-FLOTATION SKIMMINGS
USING THERMAL ENHANCEMENT
G. E. (Edd) Valentine, Jr., Senior Research Scientist
James L. Walsh, Jr., Senior Research Engineer
Georgia Tech Research Institute
Georgia Institute of Technology
Atlanta, Georgia 30332
INTRODUCTION
Thermally Enhanced Dewatering (TED) is a process developed at the Georgia Tech Research
Institute which uses low temperature heat (less than 200°F) to remove water from the skimmings
derived as a byproduct of dissolved air flotation treatment of poultry processing wastewater. The
basic principle on which the process is based is that heating the skimmings greatly increased the rate of
solid/liquid separation. Based on the successful results of the laboratory tests, a program was initiated
to develop a full-scale thermally enhanced skimmings dewatering system. The program involved
laboratory-scale beaker tests, bench-scale tank tests, pilot-scale batch tests, and pilot-scale continuous
tests.
BACKGROUND
Poultry processing plants rely heavily on the use of water in almost every step of their operations. A
typical poultry plant uses somewhere between 4 to 8 gallons per bird processed and discharge 0.8 to
1.2 MGD of wastewater. The industry discharges large volumes of wastewater from the processing of
over five billion chickens annually in the United States. The growing impact of the cost of water and
sewer on poultry processing is illustrated in Figure 1. The figure compares the cost per pound of
processed ready to cook (RTC) chicken to the cost per 1,000 gallons for water and sewer. As shown
the water and sewer costs have increased dramatically (approximately a 10-fold increase) over the time
period while poultry prices have only increased by a factor of two.1
$2 60
$2 AG
$2 20
|2 00
$1 80
$1 60
$1*0
|I.20
$1.00
$0.60
$0 60
$0*0
$0 20
$0.00
TTPICAL  GAINESVILLE.   GA
i\ v-*
ra
1060
IV'1 BROILER   RTC
TEAR
W2 WATER AMD   SEWER
Figure 1.   Comparison of broiler and water costs.
44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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