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STUDIES OF THE UPTAKE OF HEAVY METALS BY ACTIVATED SLUDGE Gilbert Elenbogen, Research Chemist II Bernard Sawyer, Research Chemist III Cecil Lue-Hing, Director of Research and Development K. C. Rao, Biostatistician David R. Zenz, Coordinator of Research Research and Development Department The Metropolitan Sanitary District of Greater Chicago Chicago, Illinois 60611 INTRODUCTION At present, the Metropolitan Sanitary District of Greater Chicago (District) is employing a number of sludge management options which allow the nutrient and soil building properties of sludge to be beneficially recycled to the environment. One drawback of these programs has been the concern, by some, regarding the effects of heavy metals, particularly cadmium (Cd), on the land to which the sludge is applied, and the uptake of Cd by crops grown on this land. Some investigators and regulatory agencies have indicated that the Cd content of the sludge is the limiting factor governing the amount of sludge which can be applied at a given site. Since the majority of sludge produced at District treatment facilities is composed of waste-activated sludge from the activated sludge process, it is clear that any reduction in the metal concentrations in waste-activated sludge would have a significant impact on metal concentrations in the digested sludges used for land application. Several basic approaches have been proposed for reducing waste-activated sludge metal concentrations. These include: 1. Reducing influent metal loadings to the treatment facilities; 2. Reducing sludge metal concentrations by physical or chemical treatment of the sludge; 3. Reducing sludge metal concentrations by operational changes to the wastewater treatment process. Of the approaches listed, the District has directed its efforts to the first approach through its Industrial Waste Control Ordinance. This approach has reduced raw sewage metal loadings to District treatment facilities by limiting industrial discharges of heavy metals and other pollutants to the District's sewer system [1]. The second approach does not appear feasible at this time, due to the fact that high capital and operating costs would be required to treat the large volumes of sludge produced at the District. In the present study, the third approach was explored; namely, reducing sludge metal concentrations by operational changes to the wastewater treatment process. DISCLAIMER The mention of trade names or commercial products does not constitute endorsement or recommendation for use by the Metropolitan Sanitary District of Greater Chicago. LITERATURE REVIEW The removal (the difference between the influent and effluent concentration) of heavy metals from wastewater by the activated sludge process has been reported by a number of investigators. Lester et al. [2[ reported that the removals of copper (Cu), cadmium (Cd), and lead (Pb) were 79, 63, and 73%, respectively, through the activated sludge system. Oliver and Cosgrove [3[ reported 71, 78, and 91% removal efficiencies for Cu, Cd, and Pb, respectively, at a Canadian sewage treatment facility. 493
Object Description
Purdue Identification Number | ETRIWC198550 |
Title | Studies of the uptake of heavy metals by activated sludge |
Author |
Elenbogen, Gilbert Sawyer, Bernard M. Lue-Hing, Cecil Rao, K. C. Zenz, David R. |
Date of Original | 1985 |
Conference Title | Proceedings of the 40th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,36131 |
Extent of Original | p. 493-506 |
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 | 2009-07-15 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 493 |
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 | STUDIES OF THE UPTAKE OF HEAVY METALS BY ACTIVATED SLUDGE Gilbert Elenbogen, Research Chemist II Bernard Sawyer, Research Chemist III Cecil Lue-Hing, Director of Research and Development K. C. Rao, Biostatistician David R. Zenz, Coordinator of Research Research and Development Department The Metropolitan Sanitary District of Greater Chicago Chicago, Illinois 60611 INTRODUCTION At present, the Metropolitan Sanitary District of Greater Chicago (District) is employing a number of sludge management options which allow the nutrient and soil building properties of sludge to be beneficially recycled to the environment. One drawback of these programs has been the concern, by some, regarding the effects of heavy metals, particularly cadmium (Cd), on the land to which the sludge is applied, and the uptake of Cd by crops grown on this land. Some investigators and regulatory agencies have indicated that the Cd content of the sludge is the limiting factor governing the amount of sludge which can be applied at a given site. Since the majority of sludge produced at District treatment facilities is composed of waste-activated sludge from the activated sludge process, it is clear that any reduction in the metal concentrations in waste-activated sludge would have a significant impact on metal concentrations in the digested sludges used for land application. Several basic approaches have been proposed for reducing waste-activated sludge metal concentrations. These include: 1. Reducing influent metal loadings to the treatment facilities; 2. Reducing sludge metal concentrations by physical or chemical treatment of the sludge; 3. Reducing sludge metal concentrations by operational changes to the wastewater treatment process. Of the approaches listed, the District has directed its efforts to the first approach through its Industrial Waste Control Ordinance. This approach has reduced raw sewage metal loadings to District treatment facilities by limiting industrial discharges of heavy metals and other pollutants to the District's sewer system [1]. The second approach does not appear feasible at this time, due to the fact that high capital and operating costs would be required to treat the large volumes of sludge produced at the District. In the present study, the third approach was explored; namely, reducing sludge metal concentrations by operational changes to the wastewater treatment process. DISCLAIMER The mention of trade names or commercial products does not constitute endorsement or recommendation for use by the Metropolitan Sanitary District of Greater Chicago. LITERATURE REVIEW The removal (the difference between the influent and effluent concentration) of heavy metals from wastewater by the activated sludge process has been reported by a number of investigators. Lester et al. [2[ reported that the removals of copper (Cu), cadmium (Cd), and lead (Pb) were 79, 63, and 73%, respectively, through the activated sludge system. Oliver and Cosgrove [3[ reported 71, 78, and 91% removal efficiencies for Cu, Cd, and Pb, respectively, at a Canadian sewage treatment facility. 493 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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