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25 A STUDY OF ANAEROBIC SEQUENCING BATCH REACTORS FOR THE TREATMENT OF SOLUBLE WASTES W. A. Sanchez, Consultant K. Kennedy, Research Officer Division of Biological Sciences National Research Council of Canada Ottawa, Canada K1A OR6 M. F. Hamoda, Professor Department of Civil Engineering Kuwait University Kuwait R. L. Droste, Associate Professor Department of Civil Engineering University of Ottawa Ottawa, Canada KIN 6N5 INTRODUCTION Sequencing batch reactors (SBRs) are fill-and-draw periodic systems which are successfully being used in activated sludge treatment. As described by Arora et al.} SBR technology is not new and in fact preceded the use of continuous-flow activated sludge technology. However, SBRs were forgotten for over half a century and were only revived in the early 1970s by the work of Irvine and Davis.2 The basic characteristics of single and multiple-tank SBR systems are described by Irvine and Busch.3 The single tank system is well suited for non-continuous flow situations, such as those that occur in the food-processing industry or in small rural towns. Multiple-tank systems are applicable for constant or variable continuous flows. To date, SBR technology has been applied only to aerobic biological processes. For these, the advantages of SBR over continuous-flow systems cited in the literature include operational flexibility, flow equalization, near-ideal settling, simple operation and compact layout of system. Reports on the intermittent operation of anaerobic processes are scarce and limited in scope. Asinari di San Marzano et al} examined the effect of semi-continuous loadings on reactor performance. Laboratory scale experiments were conducted with anaerobic digesters treating paunch and bovine manure. The following waste loadings were tested: biweekly loadings for hydraulic retention times (HRT) of 20 days; 3 times a week for HRTs between 12 and 17 days; and, once a day, 5 days a week for HRTs below 10 days. The authors concluded that semi-continuous loadings appeared more reliable than continuous loadings but recommended that no more than 20% of the digestion mixed liquor be replaced at any one time. Farrell et al} investigated the effects on microbial densities and other process parameters of changing the feeding protocol of anaerobic digesters from "draw down, then fill" (D/F) to "fill, then draw down" (F/D). They did not observe any significant effect on volatile solids or COD reductions. They, however, noted that a D/F feeding protocol resulted in improved reductions of viruses and bacterial fecal indicators in digester effluents. A mathematical analysis comparing treatment efficiencies and kinetics between sequencing batch and complete mixed systems has been presented by Droste.6 The use of anaerobic SBRs for the treatment of coal conversion wastewaters has been proposed7 but only limited data have been reported so far. The application of SBR technology to anaerobic treatment is of interest due to its inherent operational flexibility. Important potential advantages of SBRs that merit investigation include: • ability of process to handle periodic flows; • possibility of taking tanks on and off-line to meet either short-term or seasonal variations; 44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118. Printed in U.S.A. 235
Object Description
Purdue Identification Number | ETRIWC198925 |
Title | Study of anaerobic sequencing batch reactors for the treatment of soluble wastes |
Author |
Sanchez, W. A. Kennedy, K. J. Hamoda, M. F. (Mohamed F.) Droste, R. L. |
Date of Original | 1989 |
Conference Title | Proceedings of the 44th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,40757 |
Extent of Original | p. 235-246 |
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 | 2009-08-18 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 235 |
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 | 25 A STUDY OF ANAEROBIC SEQUENCING BATCH REACTORS FOR THE TREATMENT OF SOLUBLE WASTES W. A. Sanchez, Consultant K. Kennedy, Research Officer Division of Biological Sciences National Research Council of Canada Ottawa, Canada K1A OR6 M. F. Hamoda, Professor Department of Civil Engineering Kuwait University Kuwait R. L. Droste, Associate Professor Department of Civil Engineering University of Ottawa Ottawa, Canada KIN 6N5 INTRODUCTION Sequencing batch reactors (SBRs) are fill-and-draw periodic systems which are successfully being used in activated sludge treatment. As described by Arora et al.} SBR technology is not new and in fact preceded the use of continuous-flow activated sludge technology. However, SBRs were forgotten for over half a century and were only revived in the early 1970s by the work of Irvine and Davis.2 The basic characteristics of single and multiple-tank SBR systems are described by Irvine and Busch.3 The single tank system is well suited for non-continuous flow situations, such as those that occur in the food-processing industry or in small rural towns. Multiple-tank systems are applicable for constant or variable continuous flows. To date, SBR technology has been applied only to aerobic biological processes. For these, the advantages of SBR over continuous-flow systems cited in the literature include operational flexibility, flow equalization, near-ideal settling, simple operation and compact layout of system. Reports on the intermittent operation of anaerobic processes are scarce and limited in scope. Asinari di San Marzano et al} examined the effect of semi-continuous loadings on reactor performance. Laboratory scale experiments were conducted with anaerobic digesters treating paunch and bovine manure. The following waste loadings were tested: biweekly loadings for hydraulic retention times (HRT) of 20 days; 3 times a week for HRTs between 12 and 17 days; and, once a day, 5 days a week for HRTs below 10 days. The authors concluded that semi-continuous loadings appeared more reliable than continuous loadings but recommended that no more than 20% of the digestion mixed liquor be replaced at any one time. Farrell et al} investigated the effects on microbial densities and other process parameters of changing the feeding protocol of anaerobic digesters from "draw down, then fill" (D/F) to "fill, then draw down" (F/D). They did not observe any significant effect on volatile solids or COD reductions. They, however, noted that a D/F feeding protocol resulted in improved reductions of viruses and bacterial fecal indicators in digester effluents. A mathematical analysis comparing treatment efficiencies and kinetics between sequencing batch and complete mixed systems has been presented by Droste.6 The use of anaerobic SBRs for the treatment of coal conversion wastewaters has been proposed7 but only limited data have been reported so far. The application of SBR technology to anaerobic treatment is of interest due to its inherent operational flexibility. Important potential advantages of SBRs that merit investigation include: • ability of process to handle periodic flows; • possibility of taking tanks on and off-line to meet either short-term or seasonal variations; 44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118. Printed in U.S.A. 235 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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