Section 10. LAUNDRY WASTES
TREATMENT OF EMULSIFIED AND COLLOIDAL INDUSTRIAL
WASTEWATER USING A COMBINED ULTRAFILTRATION—
CARBON ADSORPTION PROCESS
Gerard J. Van Gils, Director
Environmental and Mechanical Engineering
Aratex Services, Inc.
Encino, California 91316
Massoud Pirbazari, Assistant Professor
Sung-Hyun Kim, Research Assistant
Department of Civil Engineering
University of Southern California
Los Angeles, California 90089
Jacob Shorr, President
The Memtek Corporation
Woburn, Massachusetts 01801
INTRODUCTION
The character of wastewater generated by an industrial laundry is a function of the customer group
served. The typical industrial laundry (SIC 7218) provides garments and dust control products to the
heavy manufacturing industries, the electroplating and automotive industries, battery manufacturers,
the service industries, newspapers, printers, auto garages, schools, commercial and retail businesses.
From these customers, contaminants such as oils and greases, heavy metals and solvents may be carried in on garments, coveralls, shop towels, mops or track-off mats. The U.S. Environmental Protection Agency (EPA) has analyzed laundries and characterized their wastes [1]. Most notable about this
characterization is: (1) the ubiquitousness of priority pollutants; and (2) the wide variability in waste
concentrations from laundry to laundry. Typical pollutant concentrations for laundry wastewater are
presented in Table I.
Treatment systems used for the pretreatment of such wastes prior to discharge to publicly owned
tteatment works (POTW's) use chemical coagulation and flocculation in conjunction with dissolved
air flotation for separation of flocculant solids from the water phase. Vacuum filtration is used to
dewater the float solids [1].
These treatment systems are primarily designed to remove heavy metals such as lead, cadmium,
copper, zinc and emulsified oils and greases. Dissolved solids, color materials, taste and odor compounds were generally not taken into consideration since the system effluent was most commonly
discharged to the POTW and not reused.
A previous work [2] using a spirally wound ultrafiltration membrane followed by a fixed bed activated carbon adsorption system was plagued by early fouling of the membranes, low flux rates, and
the unsolved problem of ultrafiltration concentrate containing the incompatible pollutants. Additionally, several systems have been studied for treatment of commercial laundry wastes such as in a series
of studies by the U.S. Army on the treatment of field laundry wastewaters by chemical coagulants and
activated carbon [3] and a study of the ultrafiltration process using a synthetic laundry waste [4].
Ultrafiltration has also been used to treat highly concentrated oil in water emulsions [5].
The Need for Improved Technology
Wastewater treatment costs ranged $4.00 to $5.00 per 1000 gallons using the chemical coagulation
and dissolved air flotation systems with treatment chemicals comprising the largest component costs
of $2.00 to $3.00 per 1000 gallons [6]. Additionally, typical water and sewerage costs were $.60 and
$.90, respectively, in 1983 for a total water/wastewater expense of approximately $5.00 to $6.00 per
1,000 gallons for the laundry operator.
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