BIOLOGICAL TREATABILITY OF PHOTOPROCESSING
WASTEWATER: PART I
Riley N. Kinman, Professor
Knox McKee, Graduate Student
Bob Mackey, Graduate Student
Department of Civil and Environmental Engineering
University of Cincinnati
Cincinnati, Ohio 45221
David L. Nutini, General Manager
RNK Environmental, Inc.
Covington, Kentucky 41017
Nancy Neely, Manager of Environmental Affairs
Fotomat Corporation
Wilton, Connecticut 06897
INTRODUCTION
A municipal contact stabilization activated sludge wastewater treatment plant receiving photo-
processing wastewater along with other industrial wastewaters was periodically having problems
meeting its NPDES permit. Therefore, biological treatability studies were initiated to determine the
effect of a photoprocessing wastewater upon a contact stabilization plant. A pilot bench scale
activated sludge control plant and an idential test plant were constructed. The two treatment plants
were operated at approximately the same solids levels and in the same contact stabilization mode as
the municipal plant. This paper includes the data from operation of the control plant and test plant
treating combined municipal and photoprocessing wastewater by the contact stabilization activated
sludge process.
DESIGN OF THE STUDY
Operation parameters were obtained from the municipal plant officials for the solids loadings
maintained at the plant. These same approximate loadings were used in both the control and test
plants. A contact aeration tank solids loading of 2,000 to 3,000 mg/l suspended solids and a stabilization tank solids loading of 8,000 to 10,000 mg/l suspended solids were selected based upon the
Municipal POTW. Test and control pilot plants were operated at these levels.
Maximum ratio of the photoprocessing wastewater to the Municipal POTW was determined to be
4% by volume. This 4% ratio of test to control was used in the study. The difference in total volume
was made up by the same wastewater used in the control plant. This wastewater was taken from the influent channel to the Cincinnati MSD Little Miami River POTW.
An analysis of the Little Miami Wastewater and of the photoprocessing wastewater is shown in
Table I. Wastewater from the Little Miami was collected twice a week. This wastewater was mostly
municipal but had some plating and dyeing operations discharging to it. The photoprocessing wastewater used in this test plant consisted of wastes from C41, EP2 and R100 color processes and from
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