page 262 
Previous  1 of 13  Next 


Loading content ...
Oxygen Response and Aeration in Steams ROBERT DRESNACK, Assistant Professor IVAN METZGER, Professor Department of Civil Engineering Newark College of Engineering Newark, New Jersey INTRODUCTION The response of oxygen to transient pollutional inputs may be described by a numerical solution of a partial differential equation describing the basic material balance. The stability of the method of solution depends on the relative values of the diffusive and convective fluxes while the actual response is most sensitive to lowerorder terms. Since stability is insured for the range of relative values of the flux terms which apply to streams, attention is focused on the sensitivity of response to the lowerorder terms such as aeration. A physical model of the mechanism of aeration is based on the concept that an interfacial liquid film is in a continuous state of random renewal by turbulent fluid from beneath the surface. BASIC EQUATIONS The temporal and spacial distribution of BOD in a stream for onedimensional flow is given by * 9^ = D, 9!k  H9L . (K + K3)L t La (1) at LaiF ax where L is the BOD concentration at any time, t. at a location x. The first term in Equation 1 describes the effect of longitudinal dispersion, DL, and the second term, that of velocity, U. The decay or production represented by the third term is assumed to follow first order kinetics which is the sum of two distinct processes. A continuing decay due to oxidation is represented by K,. All other processes, such as settling or resuspension, are represented by K3 which can be either positive or negative. The last term, La, describes a uniform addition of BOD along a stretch. A similar equation describing the temporal and spacial distribution of dissolved oxygen, C, is f = °L H ^K.L.K^ODB (2) where the first three terms are analogous to those in Equation 1. Atmospheric aeration is described by a firstorder reaction with coefficient, K2, and a driving force equal to the difference between the saturation concentration of oxygen, Cs, and the concentration C in the stream at any time. The net rate of addition of oxygen by all other processes is represented by Dg. This term is positive if the predominant processes are the removal of oxygen by plant respiration and the oxygen demand of the bottom sludge or negative if photosynthetic addition predomi  262 
Object Description
Purdue Identification Number  ETRIWC196823 
Title  Oxygen response and aeration in streams 
Author 
Dresnack, Robert Metzger, Ivan 
Date of Original  1968 
Conference Title  Proceedings of the 23rd Industrial Waste Conference 
Conference Front Matter (copy and paste)  http://earchives.lib.purdue.edu/u?/engext,15314 
Extent of Original  p. 262274 
Series 
Engineering extension series no. 132 Engineering bulletin v. 53, no. 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  20090520 
Capture Device  Fujitsu fi5650C 
Capture Details  ScandAll 21 
Resolution  300 ppi 
Color Depth  8 bit 
Description
Title  page 262 
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  Oxygen Response and Aeration in Steams ROBERT DRESNACK, Assistant Professor IVAN METZGER, Professor Department of Civil Engineering Newark College of Engineering Newark, New Jersey INTRODUCTION The response of oxygen to transient pollutional inputs may be described by a numerical solution of a partial differential equation describing the basic material balance. The stability of the method of solution depends on the relative values of the diffusive and convective fluxes while the actual response is most sensitive to lowerorder terms. Since stability is insured for the range of relative values of the flux terms which apply to streams, attention is focused on the sensitivity of response to the lowerorder terms such as aeration. A physical model of the mechanism of aeration is based on the concept that an interfacial liquid film is in a continuous state of random renewal by turbulent fluid from beneath the surface. BASIC EQUATIONS The temporal and spacial distribution of BOD in a stream for onedimensional flow is given by * 9^ = D, 9!k  H9L . (K + K3)L t La (1) at LaiF ax where L is the BOD concentration at any time, t. at a location x. The first term in Equation 1 describes the effect of longitudinal dispersion, DL, and the second term, that of velocity, U. The decay or production represented by the third term is assumed to follow first order kinetics which is the sum of two distinct processes. A continuing decay due to oxidation is represented by K,. All other processes, such as settling or resuspension, are represented by K3 which can be either positive or negative. The last term, La, describes a uniform addition of BOD along a stretch. A similar equation describing the temporal and spacial distribution of dissolved oxygen, C, is f = °L H ^K.L.K^ODB (2) where the first three terms are analogous to those in Equation 1. Atmospheric aeration is described by a firstorder reaction with coefficient, K2, and a driving force equal to the difference between the saturation concentration of oxygen, Cs, and the concentration C in the stream at any time. The net rate of addition of oxygen by all other processes is represented by Dg. This term is positive if the predominant processes are the removal of oxygen by plant respiration and the oxygen demand of the bottom sludge or negative if photosynthetic addition predomi  262  
Resolution  300 ppi 
Color Depth  8 bit 
Tags
Comments
Post a Comment for page 262