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PREDICTIVE MODEL FOR TREATMENT OF PHENOLIC WASTES BY ACTIVATED SLUDGE Alan Rozich, Research Assistant Anthony F. Gaudy, Jr., Professor Peter D'Adamo, Research Assistant Department of Civil Engineering University of Delaware Newark, Delaware 19711 It is well know that certain toxic organic compounds, e.g., phenol or benzene, can serve as sources of carbon for heterotrophic microorganisms and are thus susceptible to biological treatment. There is much interest in phenol because the production of phenolic wastes can be expected to increase due to greater reliance on coal for energy and base organic chemicals. Although fundamental metabolic and kinetic studies on removal of toxic organics are not abundant, those which have been done are largely concerned with phenol. Thus, phenol is becoming the most-used model compound for the study of inhibitory organics as glucose has been for the study of metabolic mechanisms and kinetics for noninhibitory organics. As far back as 1929, Mohlmann reported that low levels of phenol could be successfully treated by activated sludge [ 1]. Interest in the treatment of phenolic wastes has not waned and there are several papers available which discuss general design and operational guidelines for biological treatment of wastes containing phenolic compounds. The general consensus is that the presence of phenolics enhances susceptibility of a biological process to periodic upsets [2-4]. Several interesting case histories are available. For example, Capestany et al. [5] reported that an activated sludge plant fed phenol at 1000 mg/1 and operated with a mean hydraulic retention time of 24 hr produced an effluent phenol concentration of 0.5 mg/1. These writers also noted that sulfur was a key nutrient for success of the treatment process. Kostenbader and Flecksteiner [6] also reported low effluent levels of phenol (less than 1 mg/1) for biological treatment of coke plant ammonia liquor. Volesky et al. [7] found that effluent phenol concentrations of less than 0.2 mg/1 could be produced using a 24-hr mean hydraulic retention time for a combined waste in which the influent phenol concentration was 120 mg/1. Adams [8] reported similar results using a 2-day detention time. In their pilot plant studies, Holladay et al. [9] compared the performance of three types of biological reactors degrading phenol—stirred tank, fluidized bed and packed bed. They concluded that activated sludge was the least desirable since it exhibited the lowest degradation rate and was subject to operational upset. The results of several kinetic studies indicate conflicting conclusions regarding the need for incorporation of an inhibition function in model equations for predicting effluent substrate and biomass levels in fluidized (activated sludge) reactors treating inhibitory substrates. Neufeld and Valiknac [10] reported that the Monod model for nonhibitory substrates could suffice for expressing the relationship between specific growth rate and substrate concentration for inhibitory substrates. Also, Beltrame et al. [ 11 ], as a result of batch studies, reported finding no inhibition by phenol at high concentrations. However, a graph depicting some of the kinetic experiments shows a lower substrate utilization rate with increasing initial phenol concentration. In a second study [12], these workers found no inhibition in a continuous stirred reactor employing cell recycle. They also felt that the normal Monod expression was sufficient to relate specific growth rate to substrate concentration. On the other hand, Sokol and Howell [13] have recently conducted batch growth studies using a pure culture harvested from a continuous growth reactor and found that the sub- 619
Object Description
Purdue Identification Number | ETRIWC198266 |
Title | Predictive model for treatment of phenolic wastes by activated sludge |
Author |
Rozich, Alan F. Gaudy, Anthony F. D'Adamo, Peter C. |
Date of Original | 1982 |
Conference Title | Proceedings of the 37th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,32749 |
Extent of Original | p. 619-640 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-07-14 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 619 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | PREDICTIVE MODEL FOR TREATMENT OF PHENOLIC WASTES BY ACTIVATED SLUDGE Alan Rozich, Research Assistant Anthony F. Gaudy, Jr., Professor Peter D'Adamo, Research Assistant Department of Civil Engineering University of Delaware Newark, Delaware 19711 It is well know that certain toxic organic compounds, e.g., phenol or benzene, can serve as sources of carbon for heterotrophic microorganisms and are thus susceptible to biological treatment. There is much interest in phenol because the production of phenolic wastes can be expected to increase due to greater reliance on coal for energy and base organic chemicals. Although fundamental metabolic and kinetic studies on removal of toxic organics are not abundant, those which have been done are largely concerned with phenol. Thus, phenol is becoming the most-used model compound for the study of inhibitory organics as glucose has been for the study of metabolic mechanisms and kinetics for noninhibitory organics. As far back as 1929, Mohlmann reported that low levels of phenol could be successfully treated by activated sludge [ 1]. Interest in the treatment of phenolic wastes has not waned and there are several papers available which discuss general design and operational guidelines for biological treatment of wastes containing phenolic compounds. The general consensus is that the presence of phenolics enhances susceptibility of a biological process to periodic upsets [2-4]. Several interesting case histories are available. For example, Capestany et al. [5] reported that an activated sludge plant fed phenol at 1000 mg/1 and operated with a mean hydraulic retention time of 24 hr produced an effluent phenol concentration of 0.5 mg/1. These writers also noted that sulfur was a key nutrient for success of the treatment process. Kostenbader and Flecksteiner [6] also reported low effluent levels of phenol (less than 1 mg/1) for biological treatment of coke plant ammonia liquor. Volesky et al. [7] found that effluent phenol concentrations of less than 0.2 mg/1 could be produced using a 24-hr mean hydraulic retention time for a combined waste in which the influent phenol concentration was 120 mg/1. Adams [8] reported similar results using a 2-day detention time. In their pilot plant studies, Holladay et al. [9] compared the performance of three types of biological reactors degrading phenol—stirred tank, fluidized bed and packed bed. They concluded that activated sludge was the least desirable since it exhibited the lowest degradation rate and was subject to operational upset. The results of several kinetic studies indicate conflicting conclusions regarding the need for incorporation of an inhibition function in model equations for predicting effluent substrate and biomass levels in fluidized (activated sludge) reactors treating inhibitory substrates. Neufeld and Valiknac [10] reported that the Monod model for nonhibitory substrates could suffice for expressing the relationship between specific growth rate and substrate concentration for inhibitory substrates. Also, Beltrame et al. [ 11 ], as a result of batch studies, reported finding no inhibition by phenol at high concentrations. However, a graph depicting some of the kinetic experiments shows a lower substrate utilization rate with increasing initial phenol concentration. In a second study [12], these workers found no inhibition in a continuous stirred reactor employing cell recycle. They also felt that the normal Monod expression was sufficient to relate specific growth rate to substrate concentration. On the other hand, Sokol and Howell [13] have recently conducted batch growth studies using a pure culture harvested from a continuous growth reactor and found that the sub- 619 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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