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15 TREATMENT OF Cr(VI) CONTAINING WASTEWATER BY ADDITION OF POWDERED ACTIVATED CARBON TO THE ACTIVATED SLUDGE PROCESS Sang Eun Lee, Director Environmental Engineering Department Korea Institute of Construction Technology Inchon, Korea Hang Sik Shin, Assistant Professor Byeong Cheon Paik, Graduate Student Department of Civil Engineering Korea Advanced Institute of Science and Technology Seoul, Korea INTRODUCTION The activated sludge process is one of the most widely used processes for the removal of organic and inorganic substances from industrial and municipal wastewaters. The disturbances in treatment performances caused by the presence of inhibitory or toxic substances in wastewater and by wide fluctuations in hydraulic and organic loads often have been encountered in conventional activated sludge operations. Therefore pretreatment facilities to control such disturbances generally preceded the activated sludge processes for treatment of various industrial wastewaters. However, since activated carbon is able to mitigate these substances, the addition of powdered activated carbon (PAC) to activated sludge aeration basin has proved to be a good alternative that could provide a practical and economical method to achieve a high quality effluent by effectively overcoming the disturbances rather than employing various pretreatment processes.1'2 Many of heavy metals that have inhibitory or toxic effects on activated sludge microorganism are present in various industrial wastewaters sometimes in very high concentration and they could upset the operation of the activated sludge process.3'4 Hexavalent chromium (Cr(VI)) is one of them which has to be removed from influent to activated sludge processes' and it has been shown that activated carbon adsorption may be an effective pretreatment method for Cr(VI) containing wastewaters.6'7'8 Therefore, the addition of PAC to the aeration tank of conventional activated sludge processes may be one possible solution for effective treatment of wastewaters containing certain levels of Cr(VI) rather than employing the activated carbon adsorption process as pretreatment. Many researchers have utilized complex wastewaters containing nonbiodegradable and inhibitory or toxic organic compounds to determine the enhancement of activated sludge performance by addition of PAC for treatment of such wastes, while there have been only few evaluations of these processes for removal of specific heavy metals.9 There is also little direct information available about control parameters representing the effectiveness of PAC for the treatment of wastewaters containing Cr(VI). The objectives of this study were therefore to evaluate the effect of PAC addition to activated sludge process for treatment of wastewaters containing Cr(Vl) and to determine the kinetic parameters of the processes with and without PAC addition for treatment of such wastewaters. EXPERIMENTAL APPARATUS AND METHODOLOGY Apparatus Two laboratory scale completely mixed, continuous-flow activated sludge reactors with internal sludge recycle were used during this study, one with PAC addition and the other without PAC addition. The schematic diagram of the experimental apparatus is shown in Figure 1. The reactors were fabricated with acrylic resin and consisted of an aeration part and an internal clarifier zone. 121
Object Description
Purdue Identification Number | ETRIWC198715 |
Title | Treatment of Cr(VI) containing wastewater by addition of powdered activated carbon to the activated sludge process |
Author |
Lee, Sang-Eun Shin, Hang Sik Paik, Byeong Cheon |
Date of Original | 1987 |
Conference Title | Proceedings of the 42nd Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,38818 |
Extent of Original | p. 121-130 |
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 | 2009-08-03 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 121 |
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 | 15 TREATMENT OF Cr(VI) CONTAINING WASTEWATER BY ADDITION OF POWDERED ACTIVATED CARBON TO THE ACTIVATED SLUDGE PROCESS Sang Eun Lee, Director Environmental Engineering Department Korea Institute of Construction Technology Inchon, Korea Hang Sik Shin, Assistant Professor Byeong Cheon Paik, Graduate Student Department of Civil Engineering Korea Advanced Institute of Science and Technology Seoul, Korea INTRODUCTION The activated sludge process is one of the most widely used processes for the removal of organic and inorganic substances from industrial and municipal wastewaters. The disturbances in treatment performances caused by the presence of inhibitory or toxic substances in wastewater and by wide fluctuations in hydraulic and organic loads often have been encountered in conventional activated sludge operations. Therefore pretreatment facilities to control such disturbances generally preceded the activated sludge processes for treatment of various industrial wastewaters. However, since activated carbon is able to mitigate these substances, the addition of powdered activated carbon (PAC) to activated sludge aeration basin has proved to be a good alternative that could provide a practical and economical method to achieve a high quality effluent by effectively overcoming the disturbances rather than employing various pretreatment processes.1'2 Many of heavy metals that have inhibitory or toxic effects on activated sludge microorganism are present in various industrial wastewaters sometimes in very high concentration and they could upset the operation of the activated sludge process.3'4 Hexavalent chromium (Cr(VI)) is one of them which has to be removed from influent to activated sludge processes' and it has been shown that activated carbon adsorption may be an effective pretreatment method for Cr(VI) containing wastewaters.6'7'8 Therefore, the addition of PAC to the aeration tank of conventional activated sludge processes may be one possible solution for effective treatment of wastewaters containing certain levels of Cr(VI) rather than employing the activated carbon adsorption process as pretreatment. Many researchers have utilized complex wastewaters containing nonbiodegradable and inhibitory or toxic organic compounds to determine the enhancement of activated sludge performance by addition of PAC for treatment of such wastes, while there have been only few evaluations of these processes for removal of specific heavy metals.9 There is also little direct information available about control parameters representing the effectiveness of PAC for the treatment of wastewaters containing Cr(VI). The objectives of this study were therefore to evaluate the effect of PAC addition to activated sludge process for treatment of wastewaters containing Cr(Vl) and to determine the kinetic parameters of the processes with and without PAC addition for treatment of such wastewaters. EXPERIMENTAL APPARATUS AND METHODOLOGY Apparatus Two laboratory scale completely mixed, continuous-flow activated sludge reactors with internal sludge recycle were used during this study, one with PAC addition and the other without PAC addition. The schematic diagram of the experimental apparatus is shown in Figure 1. The reactors were fabricated with acrylic resin and consisted of an aeration part and an internal clarifier zone. 121 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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