page 37 |
Previous | 1 of 11 | Next |
|
|
Loading content ...
Section Two PHYSICAL/BIOLOGICAL SYSTEMS 5 FLOC-LOADING BIOSORPTION CRITERIA FOR THE TREATMENT OF CARBOHYDRATE WASTEWATERS Mervyn C. Goronszy, Executive Technical Manager Transfield, Inc. Irvine, California 92715 W. Wesley Eckenfelder, Professor Environmental and Water Resources Engineering Vanderbilt University Nashville, Tennessee 37235 INTRODUCTION Biosorption is an essential mechanism in the application of biomass selectivity principles for the control of filamentous sludge bulking. A number of systems incorporating biological selector concepts have been reported over recent years showing variable success. This paper provides information on biosorption relative to floc-loading and biomass degradable fraction for a number of readily degradable carbohydrate wastewaters. Procedures which enable optimum biosorption, regeneration of biomass biosorptive capacity together with degradation kinetics, overall oxygen requirements, and sludge yield are described. Parameters which favour the selection of a non-filmentous biomass are presented. BIOSORPTION PHENOMENA Sorption of soluble organic compounds is a fundamental mechanism in the metabolism of substrate by microorganisms. This phenomenon was originally observed by Porges et al. [1] and Eckenfelder (2) but little was done with application to process design and operation until recently. Sorption can be defined as that phenomenon by which a rapid removal of soluble organics occurs upon contact of the substrate with activated sludge. This reaction is very rapid occurring in a matter of minutes. There is a limit to the mass of organics which can initially be removed by a unit mass of sludge. This limiting removal is in fundamental terms a function of the storage capacity of the biomass and the rate of biological oxidation of the substrate. A maximum removal by biosorption of 0.65 mg COD/mg VSS from skim milk was found by Porges et al. [1]. This removal was stored in the cell as glycogen which was metabolized over a three-hour period. The contact stabilization process was developed to take advantage of the adsorptive and biosorptive properties of activated sludge [3]. This process achieves 90-95% BOD and suspended solids removal with only 15-30 minutes mixing of raw sewage with a well-stabilized sludge. The removal of BOD in the activated sludge process in mediated by two principal mechanisms. The first is a physical removal by which the particulates, both organics and inerts, are enmeshed and/or adsorbed by the sludge matrix. Solubilization of adsorbent particulate organics takes place by enzymatic reactions which contribute to the net soluble organic fraction which is then available for subsequent biological degradation. Removal of soluble organics is a biological phenomenon. Porges et al. [I], Quirk [4], Eckenfelder [2,5], Goronszy et al. (6), Chang [7], Hager [8], and Flippen et al. [9] report observations of rapid, soluble organic uptake by activated sludge with a variety of substrates. Biosorptive transport mechanisms are especially significant in activated sludge systems which are configured with plug-flow hydraulics or which incorporate a short retention contacting region in order to generate similar sorptive transport conditions which occur in plug-flow systems. A high level of initial absorption can be evident in those systems where a high substrate to biomass availability 37
Object Description
Purdue Identification Number | ETRIWC198605 |
Title | Floc-loading biosorption criteria for the treatment of carbohydrate wastewaters |
Author |
Goronszy, Mervyn C. Eckenfelder, W. Wesley (William Wesley), 1926- |
Date of Original | 1986 |
Conference Title | Proceedings of the 41st Industrial Waste Conference |
Extent of Original | p. 37-47 |
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 | 2009-07-13 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 37 |
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 | Section Two PHYSICAL/BIOLOGICAL SYSTEMS 5 FLOC-LOADING BIOSORPTION CRITERIA FOR THE TREATMENT OF CARBOHYDRATE WASTEWATERS Mervyn C. Goronszy, Executive Technical Manager Transfield, Inc. Irvine, California 92715 W. Wesley Eckenfelder, Professor Environmental and Water Resources Engineering Vanderbilt University Nashville, Tennessee 37235 INTRODUCTION Biosorption is an essential mechanism in the application of biomass selectivity principles for the control of filamentous sludge bulking. A number of systems incorporating biological selector concepts have been reported over recent years showing variable success. This paper provides information on biosorption relative to floc-loading and biomass degradable fraction for a number of readily degradable carbohydrate wastewaters. Procedures which enable optimum biosorption, regeneration of biomass biosorptive capacity together with degradation kinetics, overall oxygen requirements, and sludge yield are described. Parameters which favour the selection of a non-filmentous biomass are presented. BIOSORPTION PHENOMENA Sorption of soluble organic compounds is a fundamental mechanism in the metabolism of substrate by microorganisms. This phenomenon was originally observed by Porges et al. [1] and Eckenfelder (2) but little was done with application to process design and operation until recently. Sorption can be defined as that phenomenon by which a rapid removal of soluble organics occurs upon contact of the substrate with activated sludge. This reaction is very rapid occurring in a matter of minutes. There is a limit to the mass of organics which can initially be removed by a unit mass of sludge. This limiting removal is in fundamental terms a function of the storage capacity of the biomass and the rate of biological oxidation of the substrate. A maximum removal by biosorption of 0.65 mg COD/mg VSS from skim milk was found by Porges et al. [1]. This removal was stored in the cell as glycogen which was metabolized over a three-hour period. The contact stabilization process was developed to take advantage of the adsorptive and biosorptive properties of activated sludge [3]. This process achieves 90-95% BOD and suspended solids removal with only 15-30 minutes mixing of raw sewage with a well-stabilized sludge. The removal of BOD in the activated sludge process in mediated by two principal mechanisms. The first is a physical removal by which the particulates, both organics and inerts, are enmeshed and/or adsorbed by the sludge matrix. Solubilization of adsorbent particulate organics takes place by enzymatic reactions which contribute to the net soluble organic fraction which is then available for subsequent biological degradation. Removal of soluble organics is a biological phenomenon. Porges et al. [I], Quirk [4], Eckenfelder [2,5], Goronszy et al. (6), Chang [7], Hager [8], and Flippen et al. [9] report observations of rapid, soluble organic uptake by activated sludge with a variety of substrates. Biosorptive transport mechanisms are especially significant in activated sludge systems which are configured with plug-flow hydraulics or which incorporate a short retention contacting region in order to generate similar sorptive transport conditions which occur in plug-flow systems. A high level of initial absorption can be evident in those systems where a high substrate to biomass availability 37 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Tags
Comments
Post a Comment for page 37