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Study of an Extended Aeration Plant and Effluent Effect on the Receiving Watercourse GROVER L. MORRIS, Senior Sanitary Engineer LOWELL A. VAN DEN BERG, Assistant Sanitary Engineer GORDON L. CULP, Assistant Sanitary Engineer JACK R. GECKLER, Biologist RALPH PORGES, Sanitary Engineer Director Technical Advisory and Investigations Section Division of Water Supply and Pollution Control Robert A. Taft Sanitary Engineering Center Cincinnati, Ohio INTRODUCTION Extended-aeration sewage treatment is a modification of the activated sludge process. In its basic form it consists of an aeration tank with 18 to 24 hrs' detention, a final settling tank with three to six hrs detention, and 100 per cent return of settleable solids to the aeration tank. Many modifications of this basic concept have been developed in an effort to provide better control of the process. A preliminary evaluation of extended aeration as used in the United States has been presented by Porges and Morris (1). There has been an impressive increase in the number of plants from three in 1950 to 1,224 in 1960, and to over 2,600 in 1962. The statement has often been made that the extended-aeration process is capable of producing a high-quality effluent if plants are properly designed and operated (2,3,4). When separate sludge wasting is not practiced, a clear effluent with a low BOD can be produced until the mixed liquor suspended solids build up to equilibrium, after which solids are discharged in the effluent and lower the effluent quality (5). Early studies reported lack of data on the fate of the aerobically digested sludge discharged in the plant effluent and the effect of those solids on the receiving stream (1). Recent reports indicate that it is impossible to operate an extended aeration system without sludge accumulation (5,6,7,8). It has been noted that incomplete nitrification in an extended-aeration plant can cause a substantial increase in the effluent BOD over that exerted by the solids and the small demand exerted by unassimulated organics. Generally, control of the discharge of solids in the effluent has been considered the primary factor affecting the efficiency of extended-aeration plants. Because many small plants have been built without provisions for separate sludge wasting, state agencies have been concerned about the effects of discharged solids from these plants on the receiving watercourses. To determine the effect of a basic (no control of solids) extended-aeration - 331 -
Object Description
Purdue Identification Number | ETRIWC196331 |
Title | Study of an extended aeration plant and effluent effect on the receiving watercourse |
Author |
Morris, Grover L. Van Den Berg, Lowell A. Culp, Gordon L. Geckler, Jack R. Porges, Ralph |
Date of Original | 1963 |
Conference Title | Proceedings of the eighteenth Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/cdm4/document.php?CISOROOT=/engext&CISOPTR=10285&REC=1 |
Extent of Original | p. 331-347 |
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 | 2009-05-18 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 331 |
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 | Study of an Extended Aeration Plant and Effluent Effect on the Receiving Watercourse GROVER L. MORRIS, Senior Sanitary Engineer LOWELL A. VAN DEN BERG, Assistant Sanitary Engineer GORDON L. CULP, Assistant Sanitary Engineer JACK R. GECKLER, Biologist RALPH PORGES, Sanitary Engineer Director Technical Advisory and Investigations Section Division of Water Supply and Pollution Control Robert A. Taft Sanitary Engineering Center Cincinnati, Ohio INTRODUCTION Extended-aeration sewage treatment is a modification of the activated sludge process. In its basic form it consists of an aeration tank with 18 to 24 hrs' detention, a final settling tank with three to six hrs detention, and 100 per cent return of settleable solids to the aeration tank. Many modifications of this basic concept have been developed in an effort to provide better control of the process. A preliminary evaluation of extended aeration as used in the United States has been presented by Porges and Morris (1). There has been an impressive increase in the number of plants from three in 1950 to 1,224 in 1960, and to over 2,600 in 1962. The statement has often been made that the extended-aeration process is capable of producing a high-quality effluent if plants are properly designed and operated (2,3,4). When separate sludge wasting is not practiced, a clear effluent with a low BOD can be produced until the mixed liquor suspended solids build up to equilibrium, after which solids are discharged in the effluent and lower the effluent quality (5). Early studies reported lack of data on the fate of the aerobically digested sludge discharged in the plant effluent and the effect of those solids on the receiving stream (1). Recent reports indicate that it is impossible to operate an extended aeration system without sludge accumulation (5,6,7,8). It has been noted that incomplete nitrification in an extended-aeration plant can cause a substantial increase in the effluent BOD over that exerted by the solids and the small demand exerted by unassimulated organics. Generally, control of the discharge of solids in the effluent has been considered the primary factor affecting the efficiency of extended-aeration plants. Because many small plants have been built without provisions for separate sludge wasting, state agencies have been concerned about the effects of discharged solids from these plants on the receiving watercourses. To determine the effect of a basic (no control of solids) extended-aeration - 331 - |
Resolution | 300 ppi |
Color Depth | 8 bit |
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