Tertiary Treatment and Disinfection
Of Tufted Carpet Dye Wastewater
LARRY M. STUBER, Project Engineer
Georgia Environmental Protection Division
Department of Natural Resources
Atlanta, Georgia 30334
INTRODUCTION
Dalton, Georgia is a major industrial center for manufacturing tufted carpets. The
tufted carpet industry in the United States expanded at an average rate of 13.5 percent per
year from 1965 through 1971 based on millions of square yards shipped (1). There are more
than 200 textile producing and related firms in Dalton. All water supplies and wastewater
generated in the Dalton area receives treatment in facilities operated by the Dalton Water,
Light and Sinking Fund Commission. Water requirements for the rapidly expanding textile
mills are placing increasing demands on the water resources in the area and textile dyes and
auxiliary chemicals are seriously affecting water quality in streams and rivers below Dalton.
The increasing demands on the water resources and the requirements for improved
water quality dictate a higher degree of wastewater treatment. This study was undertaken to
determine the feasibility of using ozone gas as a process for tertiary treatment and
oisinfection of tufted carpet secondary treated dye wastewater.
Tufted Carpet Industry
A majority of the industrial wastewater comes from dyeing and other carpet finishing
operations that are typically arranged as shown in Figure 1. Tufting is a dry operation in
which yarn, usually nylon, polyester, and acrylic, is inserted into a jute or polypropylene
backing by a machine that operates like an oversized sewing machine. After tufting, whole
carpet dyeing is accomplished in becks equipped with a tumbling apparatus to insure
complete contact between the yarn and the coloring materials. Dyeing and scouring are
usually performed at the same time. The beck will contain dyestuffs, carriers, wetting
agents, softeners, fixers, and other auxiliary chemicals in various combinations depending
on the yarn and the type of dyes used. The types of yarn, dyes, and auxiliary chemicals used
at a typical tufting and piece dyeing plant during a twenty-four hour period are given in
Table I (2).
After dyeing, the beck is drained to waste and water is added for rinsing. More than one
rinse may be necessary and each is dumped into the sewer. The carpet is removed from the
beck and rewet to obtain a uniform saturation. The carpet is then heat treated in steam
ovens in order to dry the carpet and set the colors. The final operation is the application of a
latex backing.
A new method for finishing tufted carpet is printing. Instead of mixing the dye in a
liquid bath, the printing process uses a paste made of gum, a wetting agent, alcohol, acid,
solvent and the dyestuff. A very small quantity of carpet is printed compared to the
quantity dyed in a beck.
AH wastewater from the dye backs, printing, wetting and extraction processes, and the
dryers is collected and passed through lint screens before being discharged to the Dalton
collection sewer. The latex waste comprises a small percentage of waste flow and is usually
collected in a sump during weekly wash up and coagulated with alum. The supernatant
from the coagulation operation is on the order of a few thousand gallons and is drained to
the sewer.
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