TREATMENT OF
DYE AND PIGMENT PROCESSING WASTEWATER
BY THE ACTIVATED SLUDGE PROCESS
Glenn M. Shaul, Physical Scientist
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
Michael W. Barnett, Graduate Student
Department of Civil and Environmental Engineering
University of Cincinnati
Cincinnati, Ohio 45221
Kenneth A. Dostal, Environmental Engineer
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
The U.S. Environmental Protection Agency (EPA) Industrial Environmental Research
Laboratory (IERL) in Cincinnati is responsible for conducting both in-house and extramural
research on the treatment of specific industrial wastewaters. The in-house research program
consists of pilot-plant evaluations of certain technologies for their ability to remove pollutants contained in these industrial wastewaters. The main objective of this program is to
define and examine key design and operational factors that may control or limit the effective
operation of wastewater treatment technologies to achieve high separation and removal of
toxic and hazardous pollutants.
As one part of the overall in-house program, this chapter discusses early results of a comprehensive research study investigating activated sludge enhancement as a treatment technology. Its purpose is to determine if powdered activated carbon (PAC) addition to an activated sludge process (ASP) results in cost effective incremental improvement in treatment of
organic industrial wastewater discharges from a dye plant. Within this objective, it is also a
study goal to determine the affect on treatment efficiencies by varying the solids retention
time (SRT), PAC dosage and reactor hydraulic design configuration.
LITERATURE REVIEW
PAC addition to the aeration basin of an ASP has been indicated as a possible treatment
technique for dye and pigment industry wastewater discharges [1]. This combination of
biological and physical processes (henceforth referred to as PAC/ASP) has been shown by
many [2-4] to be particularly effective in the treatment of wastewaters which are variable
in concentration and composition, highly colored and contain potentially toxic materials.
The benefits reported by these authors include:
• improved gross and specific organic pollutant removals,
• improved settling and dewatering ability of waste sludge,
• resistance to shock loads,
• enhanced color removal,
• reduced aerator foaming and increased aeration efficiency, and
• enhanced nitrification.
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