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Application of Aerobic Digestion to Industrial Waste Treatment EDWIN L. BARNHART, Research Associate Manhattan College Englewood Cliffs, New Jersey The principle of auto-oxidation of activated sludges has long been accepted in sanitary engineering practice. In recent years this principle has been used in designing so-called complete treatment or "total oxidation" units. In practice these units, utilizing long mixed liquor detention times, have been able to limit, to a large extent, the accumulation of excess activated sludge. Recent practice has also shown that it is possible to utilize auto-oxidation in the design of aerobic digestors as a separate treatment unit. The term "aerobic digestion" as used in this paper is related to a process wherein thickened sludges separated from their associated liquors undergo stabilization during prolonged aeration. In order to establish the feasibility of employing aerobic digestion in the treatment of the wide variety of sludges produced by industrial waste treatment, numerous laboratory and pilot plant studies have been conducted. This paper presents the results of these studies. The problems encountered in the digestion of sludge are many and varied; by and large they do not lend themselves to complete investigation at laboratory scale. It is believed, however, that the following parameters may be properly considered in laboratory studies: the ultimate reduction of volatile suspended solids and the approximate time required for that reduction; the oxygen required to bring about this solids reduction; and the susceptibility of the digested sludge to various forms of dewatering. Other parameters such as effluent, pH, alkalinity, nutrient value, and BOD are also important and the information available on these factors will also be discussed. SOLIDS REDUCTION It has been shown by several investigators that (1-2) the rate of auto- oxidation in a continuous activated sludge system may be expressed as a constant per cent of the volatile suspended solids. Studies on prolonged aeration of sludges under limited food supply have described the solids degrading in terms of a retardant reaction, the rate of reaction decreasing with aeration time. Previous work also indicates that, for any sludge, there is a definite limit to the reduction in volatile solids which may be expected. This observation is confirmed by Jaworski et al. (3) who reports that the solids reduction in 60 days is not significantly more than after 15 days aeration time. Present data, Figure 1, further illustrates this point. For the purposes of these studies it was desirable to be able to compare easily the results obtained on many different sludges. Therefore, simpler formulations than the retardant form were investigated. These investigations 612 -
Object Description
Purdue Identification Number | ETRIWC196146 |
Title | Application of aerobic digestion to industrial waste treatment |
Author | Barnhart, Edwin L. |
Date of Original | 1961 |
Conference Title | Proceedings of the sixteenth Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/cdm4/document.php?CISOROOT=/engext&CISOPTR=7917&REC=15 |
Extent of Original | p. 612-618 |
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 | 2008-09-22 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 612 |
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 fi-5650C |
Capture Details | ScandAll 21 |
Transcript | Application of Aerobic Digestion to Industrial Waste Treatment EDWIN L. BARNHART, Research Associate Manhattan College Englewood Cliffs, New Jersey The principle of auto-oxidation of activated sludges has long been accepted in sanitary engineering practice. In recent years this principle has been used in designing so-called complete treatment or "total oxidation" units. In practice these units, utilizing long mixed liquor detention times, have been able to limit, to a large extent, the accumulation of excess activated sludge. Recent practice has also shown that it is possible to utilize auto-oxidation in the design of aerobic digestors as a separate treatment unit. The term "aerobic digestion" as used in this paper is related to a process wherein thickened sludges separated from their associated liquors undergo stabilization during prolonged aeration. In order to establish the feasibility of employing aerobic digestion in the treatment of the wide variety of sludges produced by industrial waste treatment, numerous laboratory and pilot plant studies have been conducted. This paper presents the results of these studies. The problems encountered in the digestion of sludge are many and varied; by and large they do not lend themselves to complete investigation at laboratory scale. It is believed, however, that the following parameters may be properly considered in laboratory studies: the ultimate reduction of volatile suspended solids and the approximate time required for that reduction; the oxygen required to bring about this solids reduction; and the susceptibility of the digested sludge to various forms of dewatering. Other parameters such as effluent, pH, alkalinity, nutrient value, and BOD are also important and the information available on these factors will also be discussed. SOLIDS REDUCTION It has been shown by several investigators that (1-2) the rate of auto- oxidation in a continuous activated sludge system may be expressed as a constant per cent of the volatile suspended solids. Studies on prolonged aeration of sludges under limited food supply have described the solids degrading in terms of a retardant reaction, the rate of reaction decreasing with aeration time. Previous work also indicates that, for any sludge, there is a definite limit to the reduction in volatile solids which may be expected. This observation is confirmed by Jaworski et al. (3) who reports that the solids reduction in 60 days is not significantly more than after 15 days aeration time. Present data, Figure 1, further illustrates this point. For the purposes of these studies it was desirable to be able to compare easily the results obtained on many different sludges. Therefore, simpler formulations than the retardant form were investigated. These investigations 612 - |
Resolution | 300 ppi |
Color Depth | 8 bit |
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