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88 PRETREATMENT LIMITS FOR FATS, OIL AND GREASE Peter V. Cavagnaro, Senior Engineer Kenneth E. Kaszubowski, Senior Engineer Howard Needles Tammen & Bergendoff Milwaukee, Wisconsin 53224 INTRODUCTION A discrepancy exists between the information available in the literature regarding oil and grease and the information used to establish discharge limits for this material. The goal of this chapter is to present information and recommendations that will be useful in the establishment of pretreatment limits for the discharge of oil and grease material to publicly owned treatment works (POTW's). The recommendations are intended to facilitate the development of regulations that will result in efficient use of POTW treatment capacity while minimizing the cost of pretreatment for industry. The chapter is organized as follows: • Oil and Grease in Domestic Wastewater • Physical and Chemical Characteristics of Oil and Grease • Operational Problems • Pretreatment Regulations • Regulatory Approaches • Pretreatment Technology • Summary • Recommendations for Oil and Grease Limits The first sections address the amount and the character of oil and grease that is present in waste water, the nature of the pollutant, and the reasons for implementing discharge limitations for oil and grease. The next sections describe the approaches used to establish pretreatment limits, the recommendations of the federal government and professional guidance manuals and the results of a survey of local discharge limitations. The last sections address the treatability of oil and grease followed by a summary and the recommendations. OIL AND GREASE IN DOMESTIC WASTEWATER Environmental engineers and wastewater treatment plant operators are primarily aware of oil and grease in wastewater by the presence of grease balls and blockages in the collection system and by the presence of floating scum on sedimentation tanks. The oil and grease concentration for weak, medium and strong wastewaters is 50, 100, and 150 mg/L, respectively.1 Rudolfs2 conducted oil and grease analysis on a number of raw wastewater samples and found that the concentration ranged from 8.4 to 220.8 mg/L. Skimming volumes from primary treatment have been reported to range between 0.1 and 6.0 cf/MG.3 A value of 2 cf/MG would correspond to an oil and grease concentration of 14 mg/L, for an assumed specific gravity of 0.95. An analysis of a raw wastewater containing 45 mg/L oil and grease4 indicated that over half the oil and grease was colloidal, and that most of the oil and grease was in the form of glycerides of fatty acids (i.e. food fats and oils). The colloidal designation was established by the process used to separate the solids. A number of researchers have demonstrated that the concentration of oil and grease in industrial and untreated municipal wastewaters and the effluent from biological treatment follows a log-normal frequency distribution.5'6 The range of maximum to minimum values commonly varies from 5 to 1. This type of variability is not commonly addressed in pretreatment regulations. Municipal ordinances commonly require that industrial discharges not exceed a specified limit, and use grab samples taken at infrequent intervals to monitor compliance. The degree of confidence required to meet such a limit may exceed 99%. The corresponding average operating level required to meet this condition may be 20% of the regulated limit. 43rd Purdue Industrial Waste Conference Proceedings, © 1989 Lewis Publishers, Inc., Chelsea, Michigan 48118. Printed in U.S.A. 777
Object Description
Purdue Identification Number | ETRIWC198888 |
Title | Pretreatment limits for fats, oil and grease |
Author |
Cavagnaro, Peter V. Kaszubowski, Kenneth E. |
Date of Original | 1988 |
Conference Title | Proceedings of the 43rd Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,39828 |
Extent of Original | p. 777-790 |
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 | 2009-08-14 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 777 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | 88 PRETREATMENT LIMITS FOR FATS, OIL AND GREASE Peter V. Cavagnaro, Senior Engineer Kenneth E. Kaszubowski, Senior Engineer Howard Needles Tammen & Bergendoff Milwaukee, Wisconsin 53224 INTRODUCTION A discrepancy exists between the information available in the literature regarding oil and grease and the information used to establish discharge limits for this material. The goal of this chapter is to present information and recommendations that will be useful in the establishment of pretreatment limits for the discharge of oil and grease material to publicly owned treatment works (POTW's). The recommendations are intended to facilitate the development of regulations that will result in efficient use of POTW treatment capacity while minimizing the cost of pretreatment for industry. The chapter is organized as follows: • Oil and Grease in Domestic Wastewater • Physical and Chemical Characteristics of Oil and Grease • Operational Problems • Pretreatment Regulations • Regulatory Approaches • Pretreatment Technology • Summary • Recommendations for Oil and Grease Limits The first sections address the amount and the character of oil and grease that is present in waste water, the nature of the pollutant, and the reasons for implementing discharge limitations for oil and grease. The next sections describe the approaches used to establish pretreatment limits, the recommendations of the federal government and professional guidance manuals and the results of a survey of local discharge limitations. The last sections address the treatability of oil and grease followed by a summary and the recommendations. OIL AND GREASE IN DOMESTIC WASTEWATER Environmental engineers and wastewater treatment plant operators are primarily aware of oil and grease in wastewater by the presence of grease balls and blockages in the collection system and by the presence of floating scum on sedimentation tanks. The oil and grease concentration for weak, medium and strong wastewaters is 50, 100, and 150 mg/L, respectively.1 Rudolfs2 conducted oil and grease analysis on a number of raw wastewater samples and found that the concentration ranged from 8.4 to 220.8 mg/L. Skimming volumes from primary treatment have been reported to range between 0.1 and 6.0 cf/MG.3 A value of 2 cf/MG would correspond to an oil and grease concentration of 14 mg/L, for an assumed specific gravity of 0.95. An analysis of a raw wastewater containing 45 mg/L oil and grease4 indicated that over half the oil and grease was colloidal, and that most of the oil and grease was in the form of glycerides of fatty acids (i.e. food fats and oils). The colloidal designation was established by the process used to separate the solids. A number of researchers have demonstrated that the concentration of oil and grease in industrial and untreated municipal wastewaters and the effluent from biological treatment follows a log-normal frequency distribution.5'6 The range of maximum to minimum values commonly varies from 5 to 1. This type of variability is not commonly addressed in pretreatment regulations. Municipal ordinances commonly require that industrial discharges not exceed a specified limit, and use grab samples taken at infrequent intervals to monitor compliance. The degree of confidence required to meet such a limit may exceed 99%. The corresponding average operating level required to meet this condition may be 20% of the regulated limit. 43rd Purdue Industrial Waste Conference Proceedings, © 1989 Lewis Publishers, Inc., Chelsea, Michigan 48118. Printed in U.S.A. 777 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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