Comparison of Ozone Contactors for Municipal Wastewater Effluent Disinfection, Packed Column Versus Jet Scrubber

摘要

Pilot scale investigations were made comparing two ozone contactors, a jet scrubber and a packed column, for ozone utilization and effluent coliform reduction efficiency. The contactors were operated in three phases: (1) Batch operational phase contactors were operated separately under identical conditions on a batch sample of activated sludge effluent. (2) Parallel operational phase; both contactors were operated in parallel on the same activated sludge effluent. (3) Continuous operational phase; both contactors were operated on the same activated sludge effluent to achieve a specified coliform reduction. Results showed that the packed column significantly outperformed the jet scrubber with respect to microorganisms reduction. Effluent quality interfered with disinfection in both contactors, the most important variables being chemical oxygen demand (total and soluble) and organic carbon. Initial bacterial density and ozone residual were also important factors affecting log reduction of coliforms and fecal streptococci in both contractors. The packed column significantly outperformed the jet scrubber with respect to ozone utilization. Organic demand measured as TCOD, SCOD, and TOC significantly affected ozone utilization at high but not low ozone dosages. These results indicate that the use of a single stage jet scrubber type ozone contactor is not suitable for wastewater disinfection with ozone.