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Effect of Batch Discharges on Extant Biodegradation Kinetics in Activated‐Sludge Systems
The biodegradation kinetics of several toxic organic compounds were determined during the operation of two sequencing batch reactor activated‐sludge systems to evaluate the effect of specific operational changes on the degradative ability of the biomass. The length of the fill period had a dramatic effect on the measured kinetic parameters for phenol, 4‐chlorophenol, acetic acid, and monochloroacetic acid. The shortest fill period (0.08 hours) corresponding to an instantaneous food‐to‐microorganism (F:M) ratio of 106.6 kg chemical oxygen demand (COD)/kg biomass·d resulted in the greatest degradative ability with respect to the maximum specific growth rate, μ but resulted in the lowest substrate affinity (highest half‐saturation coefficient, Ks value). Longer fill periods (1.5 and 3 hours, corresponding to instantaneous F:M of 5.68 and 2.84 kg COD/kg biomass'd, respectively) resulted in monotonically decreasing μ and Ks values. In separate tests when phenol was excluded from the feed for a IS‐day period, the degradative ability of phenol was partially maintained but at a lower rate and increased affinity (lower Ks). Removing phenol from the feed also had an effect on the 4‐chlorophenol biodegradation kinetics, although no changes were made to the concentration of 4‐chlorophenol in the feed. In addition, when both phenol and 4‐chlorophenol were excluded from the feed, the degrading activity of both compounds decreased, but at different degrees. These results suggest that the way that a treatment system is operated with respect to batch discharges of toxic organic compounds can have a significant effect on measured biodegradation kinetics and consequently will affect design and operation of these systems to achieve specific effluent limits.
Effect of Batch Discharges on Extant Biodegradation Kinetics in Activated‐Sludge Systems
The biodegradation kinetics of several toxic organic compounds were determined during the operation of two sequencing batch reactor activated‐sludge systems to evaluate the effect of specific operational changes on the degradative ability of the biomass. The length of the fill period had a dramatic effect on the measured kinetic parameters for phenol, 4‐chlorophenol, acetic acid, and monochloroacetic acid. The shortest fill period (0.08 hours) corresponding to an instantaneous food‐to‐microorganism (F:M) ratio of 106.6 kg chemical oxygen demand (COD)/kg biomass·d resulted in the greatest degradative ability with respect to the maximum specific growth rate, μ but resulted in the lowest substrate affinity (highest half‐saturation coefficient, Ks value). Longer fill periods (1.5 and 3 hours, corresponding to instantaneous F:M of 5.68 and 2.84 kg COD/kg biomass'd, respectively) resulted in monotonically decreasing μ and Ks values. In separate tests when phenol was excluded from the feed for a IS‐day period, the degradative ability of phenol was partially maintained but at a lower rate and increased affinity (lower Ks). Removing phenol from the feed also had an effect on the 4‐chlorophenol biodegradation kinetics, although no changes were made to the concentration of 4‐chlorophenol in the feed. In addition, when both phenol and 4‐chlorophenol were excluded from the feed, the degrading activity of both compounds decreased, but at different degrees. These results suggest that the way that a treatment system is operated with respect to batch discharges of toxic organic compounds can have a significant effect on measured biodegradation kinetics and consequently will affect design and operation of these systems to achieve specific effluent limits.
Effect of Batch Discharges on Extant Biodegradation Kinetics in Activated‐Sludge Systems
Ellis, Timothy G. (author) / Anselm, Charles V. (author)
Water Environment Research ; 71 ; 290-298
1999-05-01
9 pages
Article (Journal)
Electronic Resource
English
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