page153 |
Previous | 1 of 12 | Next |
|
|
Loading content ...
EVALUATION OF INTERACTION KINETICS AND EQUILIBRIA FOR HEAVY METAL-SLUDGE SYSTEMS Ronald D. Neufeld, Assistant Professor Jorge Guttieriez, Graduate Student Richard A. Novak, Graduate Student Department of Civil Engineering University of Pittsburgh Pittsburgh, Pennsylvania 15261 INTRODUCTION Certain industrial effluents have associated trace levels of potentially toxic heavy metals. In natural waters these metals have been documented as interacting with sediments and accumulating in fish and wildlife, thus adversely influencing man's well being and utilization of water resources. Federal and state guidelines and limitations have been placed on trace metal discharges. Considerable efforts and dollars have been expended on the measurement of heavy metals and the development of effective and inexpensive techniques for their removal. Biological sludges, as from an activated sludge process, are similar to organic river sediments in the sense that both have been observed to have the ability to remove heavy metals from liquid wastes. Indeed, a property of all living organisms is the ability to concentrate ions within the organism against a concentration gradient. It is possible to use the natural affinities of sludges towards heavy metals as a technique to concentrate and accumulate aqueous-phase heavy metals. Previous work by Neufeld [ 1 ], Neufeld and Hermann [2], Cheng, Patterson and Minear [3] and Neufeld, Gutierrez and Novak [4] have quantified apparent distribution coefficients and equilibrium relationships between liquid-phase and biological-solid phase heavy metal concentrations. These results have demonstrated solid-liquid distribution coefficients on the order of 103 to 10 4, with resultant metal on biomass concentrations in the range of 10% to 20% by weight. While the chemical mechanism for such uptake is still ill-defined, it can be postulated that metals are sorbed onto extracellular polysaccharide polymer fibrils that are excreted by and enmesh the biological cells. For process purposes, the kinetics of such uptake and the expressions of equilibria thereby resulting must be determined. OBJECTIVE OF STUDY The objectives of this research are to use laboratory investigations to determine a suitable expression which describes the temporal accumulation of heavy metals on biological sludge, and secondly to use that expression in mathematically determining a resultant equilibrium relationship. An additional objective was defined: to expand the available data base on the equilibria of aqueous metal extraction via biological sludge to include the elements chromium VI, chromium III, nickel II, lead II and zinc II. EXPERIMENTAL APPROACH In general, the specific rate of accumulation of heavy metals on biological sludge is a function of both the physical and chemical environment ambient to the sludge in accord with a general expression of the form 153
Object Description
Purdue Identification Number | ETRIWC1977017 |
Title | Evaluation of interaction kinetics and equilibria for heavy metal-sludge systems |
Author |
Neufeld, Ronald D. Guttieriez, Jorge Novak, Richard A. |
Date of Original | 1977 |
Conference Title | Proceedings of the 32nd Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,26931 |
Extent of Original | p. 153-164 |
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 | 2009-06-30 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page153 |
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 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | EVALUATION OF INTERACTION KINETICS AND EQUILIBRIA FOR HEAVY METAL-SLUDGE SYSTEMS Ronald D. Neufeld, Assistant Professor Jorge Guttieriez, Graduate Student Richard A. Novak, Graduate Student Department of Civil Engineering University of Pittsburgh Pittsburgh, Pennsylvania 15261 INTRODUCTION Certain industrial effluents have associated trace levels of potentially toxic heavy metals. In natural waters these metals have been documented as interacting with sediments and accumulating in fish and wildlife, thus adversely influencing man's well being and utilization of water resources. Federal and state guidelines and limitations have been placed on trace metal discharges. Considerable efforts and dollars have been expended on the measurement of heavy metals and the development of effective and inexpensive techniques for their removal. Biological sludges, as from an activated sludge process, are similar to organic river sediments in the sense that both have been observed to have the ability to remove heavy metals from liquid wastes. Indeed, a property of all living organisms is the ability to concentrate ions within the organism against a concentration gradient. It is possible to use the natural affinities of sludges towards heavy metals as a technique to concentrate and accumulate aqueous-phase heavy metals. Previous work by Neufeld [ 1 ], Neufeld and Hermann [2], Cheng, Patterson and Minear [3] and Neufeld, Gutierrez and Novak [4] have quantified apparent distribution coefficients and equilibrium relationships between liquid-phase and biological-solid phase heavy metal concentrations. These results have demonstrated solid-liquid distribution coefficients on the order of 103 to 10 4, with resultant metal on biomass concentrations in the range of 10% to 20% by weight. While the chemical mechanism for such uptake is still ill-defined, it can be postulated that metals are sorbed onto extracellular polysaccharide polymer fibrils that are excreted by and enmesh the biological cells. For process purposes, the kinetics of such uptake and the expressions of equilibria thereby resulting must be determined. OBJECTIVE OF STUDY The objectives of this research are to use laboratory investigations to determine a suitable expression which describes the temporal accumulation of heavy metals on biological sludge, and secondly to use that expression in mathematically determining a resultant equilibrium relationship. An additional objective was defined: to expand the available data base on the equilibria of aqueous metal extraction via biological sludge to include the elements chromium VI, chromium III, nickel II, lead II and zinc II. EXPERIMENTAL APPROACH In general, the specific rate of accumulation of heavy metals on biological sludge is a function of both the physical and chemical environment ambient to the sludge in accord with a general expression of the form 153 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Tags
Comments
Post a Comment for page153