TEXTILE DYE PROCESS WASTE TREATMENT
WITH REUSE CONSIDERATIONS
Larry E. Shriver, Environmental Process Specialist
Henningson, Durham & Richardson, Inc.
Omaha, Nebraska 68114
Richard R. Dague, Professor
Environmental Engineering Department
University of Iowa
Iowa City, Iowa 52240
INTRODUCTION
Textile wastewaters have been treated by physical, chemical and biological operations and
processes in a variety of combinations, depending on the major goal(s) of the treatment system. Reductions in oxygen-demanding materials are often achieved by biological treatment.
Both trickling filters and activated sludge systems have been applied to this purpose. Trickling filters have been used for the treatment of high-pH textile wastes without neutralization
[ 1 ], resulting in chemical cost savings. In general, the activated sludge process can achieve
a higher degree of removal of oxygen-demanding material than can trickling filters, but a
higher degree of operational attention is required.
Other than biological treatment approaches, it has been found that alum and chlorine are
effective in reducing both organic matter and color in textile wastes [ 1 ]. Dosage requirements for alum are high (> 200 mg/1) and large amounts of chemical sludge are produced.
Chlorine has been used by itself and along with other chemicals for organic matter and color
removal. Chlorine dosage requirements have been reported to be in the 100 to 250 mg/1
range.
The purpose of this study was to evaluate the characteristics and treatability of the process wastewaters from Wansona Industries, Wadesboro, North Carolina. The basic goal was
to arrive at a treatment system that would achieve a minimum of 85% reduction in a 5-day
biochemical oxygen demand (BOD5 ) prior to discharge to the City of Wadesboro sewer system. Another goal was to achieve a high degree of removal of organics and color with the
idea of moving to more advanced treatment and effluent reuse.
Since a high degree of removal of both BOD and color was desired, the decision was made
to evaluate the treatability and to establish design criteria for the activated sludge process applied to the wastewaters of Wansona Industries.
WASTE CHARACTERIZATION
Raw waste samples were collected and analyzed for the parameters considered to be necessary for determining process application (Table I).
As indicated by the data in Table I, the Wansona wastewater is high in color and organics
(BODs aid COD) and low in suspended solids and the nutrients nitrogen and phosphorus.
The major waste sources are from sizing, dyes, soap, oils and other products typical of the
industry.
Because of the high COD-to-BOD5 ratio it was suspected that the waste might have a low
BOD exertion rate (k-rate). This would indicate that the organic content of the waste stream
biodegrades at a slower rate than many waste streams. The BOD of the raw process waste
stream was determined at various intervals over a 10-day period. The results are plotted in
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