BIOLOGICAL TREATMENT OF HIGH-STRENGTH
COKE—PLANT WASTEWATER
Daniel D. Jones, Associate Professor
J. Larry Speake, Research Technician
Johanna White, Research Technician
Joseph J. Gauthier, Associate Professor
Biology Department
University of Alabama in Birmingham
Birmingham, Alabama 35294
INTRODUCTION
Coke-plant wastewater contains a variety of compounds including phenol (300-4000 mg/1), ammonia (1300-2000 mg/1), cyanide (10-100 mg/1) and thiocyanate (10-100 mg/1) [I]. Although these
compounds are toxic to fish and other organisms, they can be removed from the wastewater by biological processes provided the physical and nutritional requirements of the microorganisms involved
in the removal process are met [2,3,4]. It is essential that the microbial population be adapted to the
treatment of this wastewater. Although it is known that municipal treatment plants contain a variety
of phenol degrading bacteria [2], immediate feeding of full-strength wastewater from a coke plant to
microorganisms from a municipal plant would not be successful. The usual procedure for start up of a
biological process to treat coke-plant wastewater is to inoculate the aeration basin with
microorganisms from municipal and/or available industrial treatment plants. The inoculum is then
fed coke-plant wastewater that has been passed through an ammonia still to lower the ammonia concentration to about 100 mg/1. The wastewater may then be diluted to further reduce toxicity. During a
period of several weeks, the proportion of ammonia still effluent is gradually increased and a microbial population develops that is more tolerant of the toxicity of this wastewater and can utilize the
constituents as nutrients.
At present, there are many treatment plants that have been adapted to the treatment of coke-plant
wastewater processed in an ammonia still. The microbial populations are highly adapted to this wastewater and can efficiently remove the phenol (200-300 mg/1), thiocyanate (200-400 mg/1) and
ammonia (5-100 mg/1) [2,5]. Several studies have shown that specific microorganisms can withstand
considerably higher concentrations of these compounds. For example, certain bacterial strains have
been reported to tolerate phenol in concentrations as high as 10,000 mg/1 [6]. Wastewaters containing
600 mg/1 ammonia have likewise been successfully treated [7]. Therefore, the objective of this project
was to determine if a microbial population that had already been adapted to ammonia stripped coke-
plant wastewater could be further acclimated to treat higher levels of ammonia and organic loading,
thus reducing the volume of wastewater to be processed in the ammonia still. If a significant reduction
in the volume of water subjected to steam stripping could be realized, then a proportionate savings in
the cost of treating the wastewater would be possible.
MATERIALS AND METHODS
Design and Operation of the Bench-Scale Reactor
The bench-scale reactors used in these experiments have been described previously [3]. The water-
jacketed aeration basin had a volume of 12 liters. Overflow from a tube in the center of the aeration
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