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FIXATION MECHANISMS IN SOLIDIFICATION/STABILIZATION OF INORGANIC HAZARDOUS WASTES Paul L. Bishop, Professor Stephen B. Ransom, Graduate Student David L. Gress, Associate Professor Department of Civil Engineering University of New Hampshire Durham, New Hampshire 03824 INTRODUCTION Approximately 40 to 60 million wet metric tons of hazardous inorganic wastes are currently generated per year in the United States, mostly in liquid sludge form. In 1980, an estimated 90% of this material was disposed of by environmentally unacceptable methods [1]. There are over 50,000 dumps and 180,000 open pits, ponds and lagoons across the nation that contain some significant amount of hazardous waste; as many as 2,000 of these sites present potentially imminent public health hazards [2], In spite of this, only four new hazardous waste facilities have been licensed anywhere in the nation in the last five years. The regulations promulgated under the Resource Conservation and Recovery Act (RCRA) have forced industry to look at alternative approaches for the disposal of hazardous wastes. Essentially, RCRA has stipulated standards for siting, design and operation of disposal facilities. One alternative for the disposal of hazardous wastes is to utilize a technique known as solidification/stabilization. Solidification refers to disposal techniques that can fixate or encapsulate wastes into a solid, cemen- titious matrix. Stabilization techniques chemically and physically bind the waste with a solidification agent [3]. Together, solidification/stabilization treatment systems: (1) improve handling and physical characteristics of the waste; (2) decrease the surface area across which transfer or loss of contained pollutants can occur; and (3) limit the solubility of or detoxify any constituents contained in the waste [4]. Solidification is a technique that has been used in Japan and Europe for many years. In the United States, solidification techniques have been practiced primarily with radioactive wastes, while less environmentally acceptable methods have usually been used for hazardous wastes. Interest has recently increased in solidification/stabilization techniques because of RCRA, since a hazardous waste can possibly be treated by this process in such a manner that it becomes non- hazardous. A waste is considered nonhazardous if its toxicity, as determined by an extraction test in accordance with specific EPA regulations, meets certain standards. These standards are such that the concentrations of specified contaminants in the leachate cannot exceed 100 times the EPA's drinking water regulations [5]. This research evaluated a solidification/stabilization process designed to trap inorganic hazardous wastes (heavy metals) within a portland cement matrix, thereby creating an essentially inert, non-hazardous product. Characteristics of the solidified/stabilized product, including compressive strength and metal concentration in the leachate, were evaluated. In addition, the influence of particle size on metal leaching rate was investigated. METHODS The wastes used for this research were synthetic wastes prepared in the laboratory. The three heavy metals used (cadmium, chromium and lead) were in the form of cadmium chloride (CdCl2), potassium dichromate (K2Cr207), and lead chloride (PbCl2), respectively. The potassium 395
Object Description
Purdue Identification Number | ETRIWC198341 |
Title | Fixation mechanisms in solidification/stabilization of inorganic hazardous wastes |
Author |
Bishop, Paul L. Ransom, Stephen B. Gress, David L. |
Date of Original | 1983 |
Conference Title | Proceedings of the 38th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,34749 |
Extent of Original | p. 395-402 |
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 | 2009-07-28 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 395 |
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 | FIXATION MECHANISMS IN SOLIDIFICATION/STABILIZATION OF INORGANIC HAZARDOUS WASTES Paul L. Bishop, Professor Stephen B. Ransom, Graduate Student David L. Gress, Associate Professor Department of Civil Engineering University of New Hampshire Durham, New Hampshire 03824 INTRODUCTION Approximately 40 to 60 million wet metric tons of hazardous inorganic wastes are currently generated per year in the United States, mostly in liquid sludge form. In 1980, an estimated 90% of this material was disposed of by environmentally unacceptable methods [1]. There are over 50,000 dumps and 180,000 open pits, ponds and lagoons across the nation that contain some significant amount of hazardous waste; as many as 2,000 of these sites present potentially imminent public health hazards [2], In spite of this, only four new hazardous waste facilities have been licensed anywhere in the nation in the last five years. The regulations promulgated under the Resource Conservation and Recovery Act (RCRA) have forced industry to look at alternative approaches for the disposal of hazardous wastes. Essentially, RCRA has stipulated standards for siting, design and operation of disposal facilities. One alternative for the disposal of hazardous wastes is to utilize a technique known as solidification/stabilization. Solidification refers to disposal techniques that can fixate or encapsulate wastes into a solid, cemen- titious matrix. Stabilization techniques chemically and physically bind the waste with a solidification agent [3]. Together, solidification/stabilization treatment systems: (1) improve handling and physical characteristics of the waste; (2) decrease the surface area across which transfer or loss of contained pollutants can occur; and (3) limit the solubility of or detoxify any constituents contained in the waste [4]. Solidification is a technique that has been used in Japan and Europe for many years. In the United States, solidification techniques have been practiced primarily with radioactive wastes, while less environmentally acceptable methods have usually been used for hazardous wastes. Interest has recently increased in solidification/stabilization techniques because of RCRA, since a hazardous waste can possibly be treated by this process in such a manner that it becomes non- hazardous. A waste is considered nonhazardous if its toxicity, as determined by an extraction test in accordance with specific EPA regulations, meets certain standards. These standards are such that the concentrations of specified contaminants in the leachate cannot exceed 100 times the EPA's drinking water regulations [5]. This research evaluated a solidification/stabilization process designed to trap inorganic hazardous wastes (heavy metals) within a portland cement matrix, thereby creating an essentially inert, non-hazardous product. Characteristics of the solidified/stabilized product, including compressive strength and metal concentration in the leachate, were evaluated. In addition, the influence of particle size on metal leaching rate was investigated. METHODS The wastes used for this research were synthetic wastes prepared in the laboratory. The three heavy metals used (cadmium, chromium and lead) were in the form of cadmium chloride (CdCl2), potassium dichromate (K2Cr207), and lead chloride (PbCl2), respectively. The potassium 395 |
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