TREATMENT OF PHOTOPROCESSING EFFLUENTS BY THE ACTIVATED-SLUDGE PROCESS

Simulated C-41 (Kodacolor film processing) and RA-4 (Ektacolor paper processing) photoeffluents were subjected to aerobic treatment. Unacclimated, activated sludge inocula were used in a respiration test in which the specific oxygen uptake rate was measured in the presence of various volumetric fractions of C-41 and RA-4 photoeffluents. Both photoeffluents had negligible effects on the respiration rate of activated sludge microorganisms at volumetric levels anticipated in practice (i.e., less than 10%). The presence of photoeffluents in unacclimated, batch-activated sludge cultures did not reduce their ability to degrade an added synthetic feed. However, these cultures did not degrade any photoeffluent components. In contrast, continuous-flow-activated sludge reactors achieved a destruction of more than 43% of the photoeffluent-derived chemical oxygen demand. A large portion of the photoeffluent-related chemical oxygen demand removal was caused by thiosulfate oxidation. Ammonia removal was low (less than 31%), and negligible nitrite and nitrate concentrations were present in the effluent of the activated sludge reactors, implying lack of nitrification. However, the ability of these reactors to degrade a synthetic feed was not reduced for photoeffluent levels up to 10% by volume.