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52 TOXICITY RESPONSE OF BIOLOGICAL PHOSPHORUS REMOVING ACTIVATED SLUDGE D.H. Zitomer, Research Assistant R.E. Speece, Centennial Professor Environmental and Water Resources Engineering Vanderbilt University Nashville, Tennessee 37235 INTRODUCTION Ordinarily, low phosphorus concentrations, in natural waters prevent overgrowth of algae and foster a balanced ecosystem. When wastewater effluents containing phosphorus are released to natural waters, algal growth can be stimulated and other deleterious eutrophic conditions may predominate. In an effort to prevent this, environmental policies have emphasized the reduction of phosphorus loads to sensitive receiving waters. For example, the Chesapeake Bay Agreement (1987) and the Great Lakes Water Quality Agreement (1978) require that effluent phosphorus concentrations be greatly reduced.1 As a result, some National Pollution Discharge Elimination System (NPDES) permits require monthly average effluent phosphorus concentrations less than 1-mg/L. To meet these stringent requirements, aluminum or iron salts are often added to wastewater. Subsequently, the metal-phosphate precipitates which form are removed by clarification. Disposal of the resulting sludge is often costly. Enhanced biological phosphorus (bio-P) removal has also been employed to meet effluent requirements. In this system, removal is accomplished by bio-P bacteria which store phosphorus in great quantities. Therefore, phosphorus can be removed in the form of bio- P waste sludge which is approximately 10% by (dry) weight phosphorus,2 in contrast to typical waste activated sludge which is approximately 2% phosphorus. Since metal salt addition often becomes unnecessary, large quantities of precipitate sludge are not produced. The biochemical reactions of bio-P removal have been studied and a fundamental understanding of the process is emerging.3"9 An anaerobic environment high in substrate followed by an aerobic environment low in substrate is essential. Anaerobically, phosphate is released, providing energy for substrate uptake and storage in the form of poly-/3-hydroxybutyrate (PHB). Subsequently, PHB is oxidized in the aerobic environment and phosphate is biologically removed to provide energy for the next anaerobic feed period. Perhaps the most characteristic feature of bio-P systems is the sequence of anaerobic and aerobic environments required for selection of a biological culture high in phosphorus content. If bio-P systems are to be optimized to reduce effluent phosphorus concentrations, an understanding of the toxicity response of enhanced phosphate removing cultures must be developed. Although little information regarding toxicity response of bio-P bacteria exists, a few researchers have studied the phenomenon. This paper focuses on the effect of acetone, phenol, 4-chlorophenol and 2,3-dichlorophenol on anaerobic phosphorus release and aerobic phosphorus uptake in bio-P systems. Acetone was studied because it is often used as a solvent for other toxicant stock solutions and its effect at high concentration is of significance to future research. Phenol, 4-chlorophenol, and 2,3-dichlorophenol were selected because they represent relatively soluble, nonvolatile priority pollutants which could be present in wastewaters treated at publicly owned treatment works. PREVIOUS INVESTIGATIONS The impact of cyanide, copper, and phenol on bio-P systems was investigated.10 Toxicant spikes at the concentrations studied did not affect phosphorus release during an initial 2-hour anaerobic period, but did affect 4-hour aerobic uptake. For example, cyanide concentrations of 3-mg/L and 5-mg/L resulted in loss of enhanced phosphorus uptake, while 1-mg/L cyanide had little effect on the process. Copper, in particular, was found to markedly inhibit phosphorus uptake. At copper concen- 49th Purdue Industrial Waste Conference Proceedings, 1994 Lewis Publishers, Chelsea, Michigan 48118. Printed in U.S.A. 481
Object Description
Purdue Identification Number | ETRIWC199452 |
Title | Toxicity response of biological phosphorus removing activated sludge |
Author |
Zitomer, D. H. Speece, Richard E. |
Date of Original | 1994 |
Conference Title | Proceedings of the 49th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,44602 |
Extent of Original | p. 481-488 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
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Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 481 |
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 | 52 TOXICITY RESPONSE OF BIOLOGICAL PHOSPHORUS REMOVING ACTIVATED SLUDGE D.H. Zitomer, Research Assistant R.E. Speece, Centennial Professor Environmental and Water Resources Engineering Vanderbilt University Nashville, Tennessee 37235 INTRODUCTION Ordinarily, low phosphorus concentrations, in natural waters prevent overgrowth of algae and foster a balanced ecosystem. When wastewater effluents containing phosphorus are released to natural waters, algal growth can be stimulated and other deleterious eutrophic conditions may predominate. In an effort to prevent this, environmental policies have emphasized the reduction of phosphorus loads to sensitive receiving waters. For example, the Chesapeake Bay Agreement (1987) and the Great Lakes Water Quality Agreement (1978) require that effluent phosphorus concentrations be greatly reduced.1 As a result, some National Pollution Discharge Elimination System (NPDES) permits require monthly average effluent phosphorus concentrations less than 1-mg/L. To meet these stringent requirements, aluminum or iron salts are often added to wastewater. Subsequently, the metal-phosphate precipitates which form are removed by clarification. Disposal of the resulting sludge is often costly. Enhanced biological phosphorus (bio-P) removal has also been employed to meet effluent requirements. In this system, removal is accomplished by bio-P bacteria which store phosphorus in great quantities. Therefore, phosphorus can be removed in the form of bio- P waste sludge which is approximately 10% by (dry) weight phosphorus,2 in contrast to typical waste activated sludge which is approximately 2% phosphorus. Since metal salt addition often becomes unnecessary, large quantities of precipitate sludge are not produced. The biochemical reactions of bio-P removal have been studied and a fundamental understanding of the process is emerging.3"9 An anaerobic environment high in substrate followed by an aerobic environment low in substrate is essential. Anaerobically, phosphate is released, providing energy for substrate uptake and storage in the form of poly-/3-hydroxybutyrate (PHB). Subsequently, PHB is oxidized in the aerobic environment and phosphate is biologically removed to provide energy for the next anaerobic feed period. Perhaps the most characteristic feature of bio-P systems is the sequence of anaerobic and aerobic environments required for selection of a biological culture high in phosphorus content. If bio-P systems are to be optimized to reduce effluent phosphorus concentrations, an understanding of the toxicity response of enhanced phosphate removing cultures must be developed. Although little information regarding toxicity response of bio-P bacteria exists, a few researchers have studied the phenomenon. This paper focuses on the effect of acetone, phenol, 4-chlorophenol and 2,3-dichlorophenol on anaerobic phosphorus release and aerobic phosphorus uptake in bio-P systems. Acetone was studied because it is often used as a solvent for other toxicant stock solutions and its effect at high concentration is of significance to future research. Phenol, 4-chlorophenol, and 2,3-dichlorophenol were selected because they represent relatively soluble, nonvolatile priority pollutants which could be present in wastewaters treated at publicly owned treatment works. PREVIOUS INVESTIGATIONS The impact of cyanide, copper, and phenol on bio-P systems was investigated.10 Toxicant spikes at the concentrations studied did not affect phosphorus release during an initial 2-hour anaerobic period, but did affect 4-hour aerobic uptake. For example, cyanide concentrations of 3-mg/L and 5-mg/L resulted in loss of enhanced phosphorus uptake, while 1-mg/L cyanide had little effect on the process. Copper, in particular, was found to markedly inhibit phosphorus uptake. At copper concen- 49th Purdue Industrial Waste Conference Proceedings, 1994 Lewis Publishers, Chelsea, Michigan 48118. Printed in U.S.A. 481 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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