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Treatment of Filamentous Bulking with Hydrogen Peroxide P. J. KELLER, Research Chemist E. I. du Pont de Nemours & Co. Wilmington, Delaware C. A. COLE, Assistant Professor Pennsylvania State University Harrisburg, Pennsylvania INTRODUCTION An activated sludge plant is usually considered to be bulked when the mixed liquor suspended solids (MLSS) settle slowly. Bulking can have several causes (I), one of which is filamentous bacteria. Bulked sludges cause two problems, suspended solids losses to the effluent and reduced MLSS. Both of these conditions lead to poor effluent quality. The growth of filamentous organisms can have several causes, including a high carbohydrate content in the feed, low nutrient supply, improper solids loading and shock loads. Several types of treatments of filamentous bulking have been used. These include wasting sludge, increasing or decreasing the air supply, by-passing or diluting the waste to change loading, addition of flocculating chemicals and chlorination of return sludge (2). These treatments have had sporadic success records and where they have worked seriously degraded effluent quality. The need for good operation at all times will not allow poor plant performance during bulking incidents. EXPERIMENTAL PROCEDURES The H202 was added at a point where good mixing and efficient contact with the sludge could be obtained. The point of addition varied with each plant as a point of convenience was chosen. Sludge volume indices were used as an indication of the settleability of the mixed liquor suspended solids. Demonstrations have been made on both conventional step aeration and completely mixed activated sludge units for domestic and industrial waste waters. The experimental results cover tests at the EPA-DC pilot plant units (100,000 gpd) and municipal and industrial waste treatment demonstrations. Results ofthe initial laboratory experiments and the EPA-DC pilot plant studies were presented in a previous paper (3). EPA-DC CONVENTIONAL UNIT At the EPA-DC pilot plant an activated sludge process was operated as step aeration with a high sludge retention time and it produced good effluents. However, adjustment to the process to reduce sludge retention time and produce an effluent to be used for further nitrification studies permitted establishment of Sphaerotilus organisms. Process variations such as wasting sludge and changing loading failed to reduce the SVI over a period of several months. Chlorination was avoided to protect the subsequent nitrifying activated sludge. H202 was added to the recycle sludge at a dose of 20 mg/1 influent flow and 40 mg/1 of recycle flow for two days. This was increased to 40 mg/1 influent flow for an additional 12 days. The actual SVI reduced from 300^400 to less than 200 within two days and then eventually to 50-60 as can be seen in Figure 1. 756
Object Description
Purdue Identification Number | ETRIWC197268 |
Title | Treatment of filamentous bulking with hydrogen peroxide |
Author |
Keller, P. J. (Philip J.) Cole, Charles A. |
Date of Original | 1972 |
Conference Title | Proceedings of the 27th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/u?/engext,20246 |
Extent of Original | p. 756-762 |
Series | Engineering extension series no. 141 |
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 | 2009-06-08 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page0756 |
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 Filamentous Bulking with Hydrogen Peroxide P. J. KELLER, Research Chemist E. I. du Pont de Nemours & Co. Wilmington, Delaware C. A. COLE, Assistant Professor Pennsylvania State University Harrisburg, Pennsylvania INTRODUCTION An activated sludge plant is usually considered to be bulked when the mixed liquor suspended solids (MLSS) settle slowly. Bulking can have several causes (I), one of which is filamentous bacteria. Bulked sludges cause two problems, suspended solids losses to the effluent and reduced MLSS. Both of these conditions lead to poor effluent quality. The growth of filamentous organisms can have several causes, including a high carbohydrate content in the feed, low nutrient supply, improper solids loading and shock loads. Several types of treatments of filamentous bulking have been used. These include wasting sludge, increasing or decreasing the air supply, by-passing or diluting the waste to change loading, addition of flocculating chemicals and chlorination of return sludge (2). These treatments have had sporadic success records and where they have worked seriously degraded effluent quality. The need for good operation at all times will not allow poor plant performance during bulking incidents. EXPERIMENTAL PROCEDURES The H202 was added at a point where good mixing and efficient contact with the sludge could be obtained. The point of addition varied with each plant as a point of convenience was chosen. Sludge volume indices were used as an indication of the settleability of the mixed liquor suspended solids. Demonstrations have been made on both conventional step aeration and completely mixed activated sludge units for domestic and industrial waste waters. The experimental results cover tests at the EPA-DC pilot plant units (100,000 gpd) and municipal and industrial waste treatment demonstrations. Results ofthe initial laboratory experiments and the EPA-DC pilot plant studies were presented in a previous paper (3). EPA-DC CONVENTIONAL UNIT At the EPA-DC pilot plant an activated sludge process was operated as step aeration with a high sludge retention time and it produced good effluents. However, adjustment to the process to reduce sludge retention time and produce an effluent to be used for further nitrification studies permitted establishment of Sphaerotilus organisms. Process variations such as wasting sludge and changing loading failed to reduce the SVI over a period of several months. Chlorination was avoided to protect the subsequent nitrifying activated sludge. H202 was added to the recycle sludge at a dose of 20 mg/1 influent flow and 40 mg/1 of recycle flow for two days. This was increased to 40 mg/1 influent flow for an additional 12 days. The actual SVI reduced from 300^400 to less than 200 within two days and then eventually to 50-60 as can be seen in Figure 1. 756 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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