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Foam Fractionation — The Effect of Salts and Low Molecular Weight Organics on ABS Removal ASHIS K. SENGUPTA, Research Associate W. O. PIPES, Associate Professor of Civil Engineering The Technological Institute Northwestern University Evanston, Illinois INTRODUCTION Foam fractionation is a process by which a solution containing a surface active solute is separated into two fractions, the foam fraction which has a higher concentration of the surface active solute than the original solution and a drain fraction depleted of surface active material. The method of effecting the separation is to cause a foam to be produced by vigorous aeration and then to separate the foam from the bulk of the solution by mechanical means. When the foam is initially produced, the surface active solute is preferentially absorbed on the air water interfaces of the bubbles and thus the foam is richer in surface active material than the residual bulk solution. If some of the water held by the foam is allowed to drain back into the residual bulk solution, further enrichment of the foam fraction is obtained. The foam fractionation process has many potential applications as a method of purification, including removal of surface active materials from sewage and industrial wastes. A recent review by Rubin and Gaden (1) presents the theoretical basis of the process and describes many of its applications. The removal of alkyl benzene sulfonates (ABS) from and the reduction of chemical oxygen demand (COD) in sewage effluents have been reported by Rubin and Everett (2) and by Eldib (3). Grieves and Wood (4) have reported the application of the foam fractionation process to treatment of petrochemical wastes. It is a common observation that most of the foam on an activated sludge aeration tank is produced near the effluent end of the tank. The usual explanation of this phenomenon is that the high concentration of organic matter near the influent end of the tank suppresses foaming but after much of the organic matter has been removed by the activated sludge organisms, the detergents are released to produce foam. However, there has not yet been reported quantitative studies by which this explanation can be evaluated. It is also usually observed that the foam produced by aeration of sewage effluents is quite stable; so stable, in fact, that it may be carried several hundred yards by the wind without breaking up. Yet a study of the foam fractionation of aqueous solutions of pure ABS, the major component of the detergents present in sewage effluents, produced the observation that ABS and distilled water did not produce a particularly stable foam (4). The research reported herein was undertaken with the objective of explaining the two observations just noted. It was postulated that organic matter in solution suppressed the production of foam from aqueous solution of ABS and that the concentrations of salts and organic matter in the effluent from biological waste treatment processes increased the stability of the foam produced. - 811 -
Object Description
Purdue Identification Number | ETRIWC196463 |
Title | Foam fractionation - the effect of salts and low molecular weight organics on abs removal |
Author |
Sengupta, Ashis K. Pipes, Wesley O. |
Date of Original | 1964 |
Conference Title | Proceedings of the nineteenth Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/u?/engext,11114 |
Extent of Original | p. 811-820 |
Series |
Engineering extension series no. 117 Engineering bulletin v. 49, no. 1(a)-2 |
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 | 2009-05-19 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 811 |
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 | Foam Fractionation — The Effect of Salts and Low Molecular Weight Organics on ABS Removal ASHIS K. SENGUPTA, Research Associate W. O. PIPES, Associate Professor of Civil Engineering The Technological Institute Northwestern University Evanston, Illinois INTRODUCTION Foam fractionation is a process by which a solution containing a surface active solute is separated into two fractions, the foam fraction which has a higher concentration of the surface active solute than the original solution and a drain fraction depleted of surface active material. The method of effecting the separation is to cause a foam to be produced by vigorous aeration and then to separate the foam from the bulk of the solution by mechanical means. When the foam is initially produced, the surface active solute is preferentially absorbed on the air water interfaces of the bubbles and thus the foam is richer in surface active material than the residual bulk solution. If some of the water held by the foam is allowed to drain back into the residual bulk solution, further enrichment of the foam fraction is obtained. The foam fractionation process has many potential applications as a method of purification, including removal of surface active materials from sewage and industrial wastes. A recent review by Rubin and Gaden (1) presents the theoretical basis of the process and describes many of its applications. The removal of alkyl benzene sulfonates (ABS) from and the reduction of chemical oxygen demand (COD) in sewage effluents have been reported by Rubin and Everett (2) and by Eldib (3). Grieves and Wood (4) have reported the application of the foam fractionation process to treatment of petrochemical wastes. It is a common observation that most of the foam on an activated sludge aeration tank is produced near the effluent end of the tank. The usual explanation of this phenomenon is that the high concentration of organic matter near the influent end of the tank suppresses foaming but after much of the organic matter has been removed by the activated sludge organisms, the detergents are released to produce foam. However, there has not yet been reported quantitative studies by which this explanation can be evaluated. It is also usually observed that the foam produced by aeration of sewage effluents is quite stable; so stable, in fact, that it may be carried several hundred yards by the wind without breaking up. Yet a study of the foam fractionation of aqueous solutions of pure ABS, the major component of the detergents present in sewage effluents, produced the observation that ABS and distilled water did not produce a particularly stable foam (4). The research reported herein was undertaken with the objective of explaining the two observations just noted. It was postulated that organic matter in solution suppressed the production of foam from aqueous solution of ABS and that the concentrations of salts and organic matter in the effluent from biological waste treatment processes increased the stability of the foam produced. - 811 - |
Resolution | 300 ppi |
Color Depth | 8 bit |
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