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Treatment of Nitrogen Deficient Organic Wastes by a Modification of the Activated Sludge Process C. V. RAMA RAO, Research Assistant R. E. SPEECE, Assistant Professor of Sanitary Engineering R. S. ENGELBRECHT, Professor of Sanitary Engineering Department of Civil Engineering University of Illinois Urbana, Illinois Biological treatment processes are commonly used to stabilize industrial waste waters containing organic pollutants. In addition to an energy source, the microorganisms responsible for the removal of the organic pollutant must also be supplied with certain inorganic nutrients in order to sustain their life processes. Domestic sewage contains adequate quantities of these inorganic nutrients to supply the demand of the microorganisms. However, many industrial waste waters do not contain sufficient nitrogen to satisfy the requirement of the microorganisms involved. Therefore, in order to satisfactorily stabilize these organically polluted waste waters, a supplemental form of nitrogen must be added. For wastes totally deficient in nitrogen this supplementation cost is normally comparable to that of the air compressor power costs when the activated sludge process is the biological treatment method used. Therefore, it is desirable in such cases to modify the operation of the activated sludge process to obtain minimum operational costs. Chasick(l)has described a modification of the activated sludge process called activated aeration. The process involved re-utilization of the excess activated sludge solids wasted from the secondary settling tank of a conventional activated sludge system. The object of this modification was to treat an additional sewage flow and obtain greater BOD removal while economizing on the amount of oxygen required. It was first used in New York to treat domestic sewage having a low BOD. The effluent was of intermediate quality and suitable for the local conditions. The excess sludge wasted from the conventional activated sludge process is active and still capable of utilizing organic matter. In the activated aeration process, advantage is taken of this capacity of the waste sludge to remove organic material on a one-pass no-recycle basis. The waste sludge is transferred to another aeration tank called an activated aerator into which the remaining portion of the primary effluent is admitted. Chasick's data showed that the MLSS concentration was very low in the activated aeration tank (75 mg/l). The contents were aerated for two hrs and allowed to settle. There was good synthesis and the final MLSS concentration was 225 mg/l. The sludge from this process was wasted. The BOD removal was 70 to 75 per cent. The flow diagram in this present study, shown in Figure 1, is the same as that of activated aeration except for the nitrogen supplementation. However, the objectives desired from its application differ considerably. First, it is proporsed for nitrogen deficient wastes, not domestic sewage, and second, high BOD removal requirements, instead of intermediate treatment, are desired. Wuhrman (2) while working with glucose acclimated sludge, subjected the bacterial cells, which were previously washed in phosphate buffer to remove ex- -427 -
Object Description
Purdue Identification Number | ETRIWC196340 |
Title | Treatment of nitrogen deficient organic wastes by a modification of the activated sludge process |
Author |
Rama Rao, C. V. Speece, Richard E. Engelbrecht, R. S. |
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. 427-446 |
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 427 |
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 | Treatment of Nitrogen Deficient Organic Wastes by a Modification of the Activated Sludge Process C. V. RAMA RAO, Research Assistant R. E. SPEECE, Assistant Professor of Sanitary Engineering R. S. ENGELBRECHT, Professor of Sanitary Engineering Department of Civil Engineering University of Illinois Urbana, Illinois Biological treatment processes are commonly used to stabilize industrial waste waters containing organic pollutants. In addition to an energy source, the microorganisms responsible for the removal of the organic pollutant must also be supplied with certain inorganic nutrients in order to sustain their life processes. Domestic sewage contains adequate quantities of these inorganic nutrients to supply the demand of the microorganisms. However, many industrial waste waters do not contain sufficient nitrogen to satisfy the requirement of the microorganisms involved. Therefore, in order to satisfactorily stabilize these organically polluted waste waters, a supplemental form of nitrogen must be added. For wastes totally deficient in nitrogen this supplementation cost is normally comparable to that of the air compressor power costs when the activated sludge process is the biological treatment method used. Therefore, it is desirable in such cases to modify the operation of the activated sludge process to obtain minimum operational costs. Chasick(l)has described a modification of the activated sludge process called activated aeration. The process involved re-utilization of the excess activated sludge solids wasted from the secondary settling tank of a conventional activated sludge system. The object of this modification was to treat an additional sewage flow and obtain greater BOD removal while economizing on the amount of oxygen required. It was first used in New York to treat domestic sewage having a low BOD. The effluent was of intermediate quality and suitable for the local conditions. The excess sludge wasted from the conventional activated sludge process is active and still capable of utilizing organic matter. In the activated aeration process, advantage is taken of this capacity of the waste sludge to remove organic material on a one-pass no-recycle basis. The waste sludge is transferred to another aeration tank called an activated aerator into which the remaining portion of the primary effluent is admitted. Chasick's data showed that the MLSS concentration was very low in the activated aeration tank (75 mg/l). The contents were aerated for two hrs and allowed to settle. There was good synthesis and the final MLSS concentration was 225 mg/l. The sludge from this process was wasted. The BOD removal was 70 to 75 per cent. The flow diagram in this present study, shown in Figure 1, is the same as that of activated aeration except for the nitrogen supplementation. However, the objectives desired from its application differ considerably. First, it is proporsed for nitrogen deficient wastes, not domestic sewage, and second, high BOD removal requirements, instead of intermediate treatment, are desired. Wuhrman (2) while working with glucose acclimated sludge, subjected the bacterial cells, which were previously washed in phosphate buffer to remove ex- -427 - |
Resolution | 300 ppi |
Color Depth | 8 bit |
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