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Methods for Operators of Wastewater Treatment Plants to Determine BOD Parameters OWEN SLETTEN, Public Health Engineer Division of Environmental Engineering Nebraska State Department of Health Lincoln, Nebraska INTRODUCTION The rate of biochemical oxidation of organic matter is a parameter of great interest and importance to the sanitary engineer, and as the writer shall endeavor to prove, also the the operators of the wastewater treatment plant. Streeter and Phelps (1) introduced the concept that the rate of biochemical oxidation is proportional to the concentration of unoxidized substance, measured in terms of oxidizability. This is a firstorder reaction, which may be written y = L(l10"'ct), where y is the BOD at time t, and L corresponds to the theoretical ultimate BOD. Many methods for calculation of BOD parameters have been developed by other investigators, such as Young and Clark, (2) Theriault, (3) Thomas, (4) Fair, (5) Wiegand, (6) Fujimoto, (7) Moore, (8) Sheehy, (9) and Navone (10). This investigator presents procedures which are quite unlike those developed by these scientists but hopefully of practical use even to the wastewater treatment plant operator who is not well grounded in mathematics. The 5day BOD is a widelyused parameter to assess wastes in water and sewage but it is the contention of the writer that the velocity of it's reaction, commonly termed the "k" parameter, is the really significant element. It is his thesis that routine determination of the k parameter can be effectively used by sewage plant operators as one of the ways of measuring efficiency of treatment of sewage or wastewater. The k parameter is a measure of the rate of progression of the biochemical oxidation. A high k rate is held to mean a rapid rate of waste decomposition. If this idea is valid, the operator should try to achieve a high k rate, since this is an indication of efficient treatment. In short, he should modify or control the operation of the treatment facility to get as high a k rate as possible. THE NATURE OF THE BOD REACTION Ideally, the BOD curve plotted on semilog graph paper, produces a smooth asymptotic line, the lower end of which approaches but never reaches the yaxis at time zero, while the upper end gradually approaches an imaginary line, parallel with the xaxis, which is equivalent to "L", the ultimate BOD. Figure 1 illustrates such an asymptotic curve, where L is equivalent to 100 mg/1, k is 0.12, and Ty2 (halflife) is 2.50 days. Halflife is the length in days, at any time during the BOD progression, required for half of the remaining waste to be oxidized. For example, if a given waste is 50 percent "destroyed" in the biochemical 740
Object Description
Purdue Identification Number  ETRIWC197168 
Title  Methods for operators of wastewater treatment plants to determine BOD parameters 
Author  Sletten, Owen 
Date of Original  1971 
Conference Title  Proceedings of the 26th Industrial Waste Conference 
Conference Front Matter (copy and paste)  http://earchives.lib.purdue.edu/u?/engext,19214 
Extent of Original  p. 740752 
Series  Engineering extension series no. 140 
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  20090625 
Capture Device  Fujitsu fi5650C 
Capture Details  ScandAll 21 
Resolution  300 ppi 
Color Depth  8 bit 
Description
Title  page 740 
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 fi5650C 
Capture Details  ScandAll 21 
Transcript  Methods for Operators of Wastewater Treatment Plants to Determine BOD Parameters OWEN SLETTEN, Public Health Engineer Division of Environmental Engineering Nebraska State Department of Health Lincoln, Nebraska INTRODUCTION The rate of biochemical oxidation of organic matter is a parameter of great interest and importance to the sanitary engineer, and as the writer shall endeavor to prove, also the the operators of the wastewater treatment plant. Streeter and Phelps (1) introduced the concept that the rate of biochemical oxidation is proportional to the concentration of unoxidized substance, measured in terms of oxidizability. This is a firstorder reaction, which may be written y = L(l10"'ct), where y is the BOD at time t, and L corresponds to the theoretical ultimate BOD. Many methods for calculation of BOD parameters have been developed by other investigators, such as Young and Clark, (2) Theriault, (3) Thomas, (4) Fair, (5) Wiegand, (6) Fujimoto, (7) Moore, (8) Sheehy, (9) and Navone (10). This investigator presents procedures which are quite unlike those developed by these scientists but hopefully of practical use even to the wastewater treatment plant operator who is not well grounded in mathematics. The 5day BOD is a widelyused parameter to assess wastes in water and sewage but it is the contention of the writer that the velocity of it's reaction, commonly termed the "k" parameter, is the really significant element. It is his thesis that routine determination of the k parameter can be effectively used by sewage plant operators as one of the ways of measuring efficiency of treatment of sewage or wastewater. The k parameter is a measure of the rate of progression of the biochemical oxidation. A high k rate is held to mean a rapid rate of waste decomposition. If this idea is valid, the operator should try to achieve a high k rate, since this is an indication of efficient treatment. In short, he should modify or control the operation of the treatment facility to get as high a k rate as possible. THE NATURE OF THE BOD REACTION Ideally, the BOD curve plotted on semilog graph paper, produces a smooth asymptotic line, the lower end of which approaches but never reaches the yaxis at time zero, while the upper end gradually approaches an imaginary line, parallel with the xaxis, which is equivalent to "L", the ultimate BOD. Figure 1 illustrates such an asymptotic curve, where L is equivalent to 100 mg/1, k is 0.12, and Ty2 (halflife) is 2.50 days. Halflife is the length in days, at any time during the BOD progression, required for half of the remaining waste to be oxidized. For example, if a given waste is 50 percent "destroyed" in the biochemical 740 
Resolution  300 ppi 
Color Depth  8 bit 
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