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Heavy Metal Removal From Wastewater Treatment Plant by Chemical Treatment CHARLES M. WEST, Water Quality Specialist Division of Water Quality Control Tennessee Department of Public Health Knoxville, Tennessee 37919 WILLIAM P. BONNER, Assistant Professor RAFAEL B. BUSTAMANTE, Associate Professor Department of Civil Engineering Tennessee Technological University Cookeville, Tennessee 38501 INTRODUCTION A great deal of interest in water quality has been shown by the public in recent years. Particular concern has been demonstrated locally for the waters and streams receiving the effluent of the Cookeville, Tennessee, sewage treatment plant. Investigation of the situation revealed several facts:l) The current treatment plant is seriously overloaded, having been designed to treat approximately two million gallons per day; 2) Sludge (solid waste) derived from the sedimentation and skimming processes are normally treated by bacterial digestion and subsequent dewatering, drying, and disposal as soil building material; 3) The effluent has a low residual chlorine content and is fairly high in solids; 4) Sudden increases in inlet flow rates after heavy rainfalls indicate contributions from storm drains for heavy leakage of surface waters; 5) Several local industries, many of which have metal treating and plating operations, are permitted to discharge their wastes into the city sewer system; and 6) An investigation to determine the cause of digester inactivity had revealed the presence of copper and chromium metals in the digester. These facts gave rise to serious concern for the quality of the effluent with respect to heavy metals. Further concern arose when it was discovered that plans had been made to increase the capacity of the current plant and to add a tertiary treatment system (chemical treatments followed by microscreening). At this point it was decided that it would be of public and scientific interest to: 1) determine the general quality of the effluent of the sewage treatment plant, with respect to heavy metals, and 2) determine the effect of the proposed tertiary treatment system on the quality of the effluent with respect to heavy metals. Because of the suspected nature of the industrial wastes contributed to the system, six heavy metals were chosen for investigation. Based on their toxicity and probability of occurrence in these effluents, the metals were chromium, nickel, cadmium, copper, lead, and mercury. The latter metal was added because of current interest in mercury pollution in streams and rivers in the Tennessee area. There was little suspicion of the presence of this metal, because its only potential source in the area would be accidental loss from pressure measuring devices, pump and similar seals, or analytical laboratory effluents. In order to acquire samples with as a high a concentration of heavy metals as possible for the general survey, grab samples were taken over a thirty-day period in the late summer (August, 1971). The average flow during this period was about two million gallons per day. The flow rate during the wetter months may be as high as four to six million gallons per day. If the metals are added at a fairly constant rate, this increase in volume could result in a two or three fold dilution and reduce the metal concentration beyond the detection limits of the analytical methods used. Samples taken for the study concerning the efficiency of the proposed treatment system were acquired in the spring (April and May, 1972), when the flow averaged four to six million gallons per day. 117
Object Description
Purdue Identification Number | ETRIWC197313 |
Title | Heavy metal removal from wastewater treatment plant by chemical treatment |
Author |
West, Charles M. Bonner, William P. Bustamante, R. B. (Rafael B.) |
Date of Original | 1973 |
Conference Title | Proceedings of the 28th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/u?/engext,23197 |
Extent of Original | p. 117-128 |
Series | Engineering extension series no. 142 |
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 | 2009-06-02 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 117 |
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 | Heavy Metal Removal From Wastewater Treatment Plant by Chemical Treatment CHARLES M. WEST, Water Quality Specialist Division of Water Quality Control Tennessee Department of Public Health Knoxville, Tennessee 37919 WILLIAM P. BONNER, Assistant Professor RAFAEL B. BUSTAMANTE, Associate Professor Department of Civil Engineering Tennessee Technological University Cookeville, Tennessee 38501 INTRODUCTION A great deal of interest in water quality has been shown by the public in recent years. Particular concern has been demonstrated locally for the waters and streams receiving the effluent of the Cookeville, Tennessee, sewage treatment plant. Investigation of the situation revealed several facts:l) The current treatment plant is seriously overloaded, having been designed to treat approximately two million gallons per day; 2) Sludge (solid waste) derived from the sedimentation and skimming processes are normally treated by bacterial digestion and subsequent dewatering, drying, and disposal as soil building material; 3) The effluent has a low residual chlorine content and is fairly high in solids; 4) Sudden increases in inlet flow rates after heavy rainfalls indicate contributions from storm drains for heavy leakage of surface waters; 5) Several local industries, many of which have metal treating and plating operations, are permitted to discharge their wastes into the city sewer system; and 6) An investigation to determine the cause of digester inactivity had revealed the presence of copper and chromium metals in the digester. These facts gave rise to serious concern for the quality of the effluent with respect to heavy metals. Further concern arose when it was discovered that plans had been made to increase the capacity of the current plant and to add a tertiary treatment system (chemical treatments followed by microscreening). At this point it was decided that it would be of public and scientific interest to: 1) determine the general quality of the effluent of the sewage treatment plant, with respect to heavy metals, and 2) determine the effect of the proposed tertiary treatment system on the quality of the effluent with respect to heavy metals. Because of the suspected nature of the industrial wastes contributed to the system, six heavy metals were chosen for investigation. Based on their toxicity and probability of occurrence in these effluents, the metals were chromium, nickel, cadmium, copper, lead, and mercury. The latter metal was added because of current interest in mercury pollution in streams and rivers in the Tennessee area. There was little suspicion of the presence of this metal, because its only potential source in the area would be accidental loss from pressure measuring devices, pump and similar seals, or analytical laboratory effluents. In order to acquire samples with as a high a concentration of heavy metals as possible for the general survey, grab samples were taken over a thirty-day period in the late summer (August, 1971). The average flow during this period was about two million gallons per day. The flow rate during the wetter months may be as high as four to six million gallons per day. If the metals are added at a fairly constant rate, this increase in volume could result in a two or three fold dilution and reduce the metal concentration beyond the detection limits of the analytical methods used. Samples taken for the study concerning the efficiency of the proposed treatment system were acquired in the spring (April and May, 1972), when the flow averaged four to six million gallons per day. 117 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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