OZONE DECOLORIZATION OF SECONDARY DYE-LADEN EFFLUENTS

摘要

The city of Dalton, Georgia includes some 200 carpet producing and related firms engaged in dyeing. Wastes from these industries, totalling 40 mgd, are treated in combination with municipal sewage in a central activated sludge plant. Grab samples, 20 gal in size, of treatment plant effluent taken during five different days in 1973 were treated by ozonization and by activated carbon to compare efficiencies.rnReduction of color of unfiltered effluent from 275 APHA units to 30 required 45 mg/l of ozone. At this dosage level COD also was reduced 40%, DO increased 325%, BOD and organics remained constant, inorganic carbon increased 67%, suspended solids decreased 85%, biphenyl decreased 51%, anionic detergents decreased 92%, fecal coliforms decreased 100% (to 0/100 ml) and total coliforms decreased 99.99%.rnCapital and operating cost comparisons between ozone and activated carbon for color removal alone and amortized over 20 years are greatly in favor of ozone ($10.7 MM over 20 years for ozone vs. $21.8 MM for activated carbon), and the effluent is disinfected. An additional disinfection step would be required after carbon treatment.