Thermoplastic Techniques

In thermoplastic processes, the waste is dried, heated, and then dispersed through a heated plastic system. Bitumen is the most common matrix material. However, paraffin and polyethylene have also been employed. The final mixture is then cooled and is usually embedded in a containment system. Organic chemicals that could react with the plastic matrix, leading to physical deterioration, cannot be disposed of with this technique. The process employs specialized equipment, is energy-intensive, and...

Set Goals and Targets and Measure Progress Quantitatively

History provides a myriad of examples, large and small, of seemingly impossible tasks accomplished in limited time frames because a dedicated group of people were given a clearly defined goal, adequate resources, and a deadline. Goals for environmental performance have been put forth voluntarily and publicly by numerous firms. In mid-1988, 3M stated that, using 1987 as a baseline, it intended to cut all hazardous and non-hazardous releases to the air, water,...

Remedy Selection Criteria

The National Contingency Plan (NCP), as revised in March 1990, sets forth the selection criteria to be used in the evaluation of remediation alternatives. Remedies are evaluated in three steps in accordance with the NCP and USEPA guidance documents 1. Identification and evaluation of remedial technologies usually targeted at one or more specific site problems 2. Combining of suitable technologies into remedial alternatives usually intended to address the entire site 3. Detailed analysis of...

Physical Agents

In almost all industrial facilities, noise is a common agent. However, engineers can reduce noise exposure easily if they address it in the design stage. The engineering design stage is the crucial time to plan for a quiet process unit. The noisy process unit usually contains sources of noise that could have been much more easily fixed before construction than after. In designing fluid flow, especially turbulent flow, vibrating pipes are quieted by (1) designing gradual bends, (2) placing...

Selection of Least Hazardous Material Alternatives

This chapter addresses the underlying purposes of accomplishing measures to select the least hazardous of alternative materials used or planned for use by industrial and governmental entities. It then discusses the relationship of substitution processes to other considerations in the decision process. An overview of some approaches for selection methods is presented. A methodology originally developed for the U.S. Navy is described, along with examples. B. Substitution Methods as an Element of...

Effect of Pore Fluid on Liner Behavior

Pore fluid effects on liner behavior have been discussed in various publications in recent years. Many of these studies considered construction impacts, settlement effects, and pore fluid-hydraulic conductivity interactions. In the following sections, selected additional factors such as changes in soil cracking patterns, swelling, shrinking, and volume as well as changes in soil particle distribution due to pollution are discussed. Soil cracks are frequently observed in natural and constructed...

Inorganic Contaminants

As previously noted, inorganic contaminants are naturally occurring substances that can become concentrated in the environment due to human activities. The principal contaminants of concern in the environment are the heavy metals. Metals on the USEPA's Target Analyte List are listed in Table 1. Heavy metals are of relatively low vapor pressure and are thus effectively nonvolatile at standard temperature and pressure. However, some of them, for example, lead and mercury, become very volatile at...

Fbc For Waste Minimization

Due to low organic emissions levels, FBC is a promising technology for disposal of organic material-laden wastes. Donlee Technologies (USA) has developed a CFBC boiler to incinerate infectious hospital wastes by cofiring with coal 16 . Based on pilot-scale testing, they report that PAH, dioxin, and furan emissions were typically well below those achieved with other types of hospital waste incinerators. Furthermore, suppression of HC1 of up to 50 was achieved. Organic emissions met both the...

Emissions of Non Methane Organic Compounds

At the hypothetical subject site presented in this chapter, landfill gas is collected and is routed to an enclosed flare. The flare oxidizes any toxic compounds present into less harmful compounds (ideally, carbon dioxide and water). Because landfill gas after combustion has a significantly lower health risk than unburned gas, the choice of the landfill gas collection system efficiency has a large effect on the final estimate of the health risks in the vicinity of the landfill. Emission factors...

Soil Wastes

Tests on the soil samples were conducted simultaneously with the research on the battery casings. Since upgrading by gravity separation, flotation, etc. were not effective, the hydromet-allurgical approach used for the casings was followed for the soils (see Figure 3). First, the as-received soil samples were characterized and chemical analyses were performed. The amount of lead in the soils varied widely, depending on the specific site and the area within that site. Partial analyses on one...

Case 1 Texas Gulf Coast Industrial Landfill Site

Before the advent of horizontal wellbore technology, vertical wells were used to recover contaminated groundwater under landfills. In aquifers with high hydraulic conductivity, vertical wells placed along the periphery of a landfill can influence the aquifer below the landfill. If the size of the plume is small compared to the size of the landfill, migration of contaminants from the core of the plume below the landfill to vertical extraction wells along the periphery spreads the contamination....

Description of Multimed

Multimed is a recently developed user-friendly computer model that is capable of simulating the release of chemicals in leachate form from a source (or designated area) at the site to soils directly beneath the source. In addition, Multimed can be used to further simulate chemical fate and transport in the unsaturated and saturated zones, followed by possible interception of the subsurface plume by a specified receptor (e.g., a well or surface stream). The fate and transport of a chemical...

Firing of Waste Biomass

CANMET has tested a number of waste biomass fuels in pilot-scale bubbling fluidized bed combustors (40 cm X 4 cm units with a total height of 5 m) 35 . The fuels that have been burned are paper waste pellets, alfa grass, wood chips, corncobs, and rice husks. Proximate analyses of the fuels, where available, operating conditions, combustion performance, and emission levels are given in Table 1. The only serious problem associated with burning these fuels was feeding them into the bed. This was...

Cavern Closure

Salt cavern repositories are ideal for safe isolation of solidified hazardous waste. The subsurface disposal facilities can be designed and constructed in such a way that there is virtually no possibility of escape of the contaminants within the time frame to perpetuity (defined as 10,000 years by EPA). Solution-mined caverns in dry domal salt meet the requisite criteria for this demonstration and provide the only plausible solution to this problem, for the foreseeable future. Fortunately, dry...

Sludge Treatment

Sludge is treated prior to ultimate disposal for two reasons volume reduction and stabilization of organics. A reduced sludge volume minimizes pumping and storage requirements and lowers sludge handling costs. Stabilized sludge has a less offensive odor, and health hazard and nuisance conditions are minimized. Common methods to accomplish the two objectives include thickening, biological digestion, dewatering, and incineration. When incineration is used, there is no need to stabilize the...

Chromate Reduction

Hexavalent chromium is toxic, and most chromates are water-soluble. Only Ba2 +, Pb2 +, Hg+, and Ag+ form insoluble chromates. Pollution with chromates is especially troublesome, since chromates are not adsorbed by soil and thus reach the groundwater table rapidly. Most chemical control strategies are based on the reduction of hexavalent chromium (Crvl) to trivalent chromium (Cr111). Trivalent chromium is much less toxic than chromates and forms a hydroxide with a solubility minimum in the pH...

Characteristics Of Contaminated Media

The media that may require remediation at any given contaminated site may include waste materials that were disposed of or spilled in the environment, soils contaminated either directly by spillage and discharges of liquids or indirectly by infiltrating contaminated water, groundwater contaminated either directly by nonaqueous-phase liquids (NAPLs) or by contaminants in solution, surface water containing nonaqueous-phase liquids and or contaminants in solution or suspension, and air, which may...

The Crystallization Section

The crystallization process is built up of three components as shown schematically in Figure 3, starting with a set of scraped surface heat exchangers (SSHEs) that remove the necessary heat from the system to provide for ice crystal formation. The SSHEs are connected to the recrys-tallizer by a recirculation stream through a scraped filter in the recrystallizer. This provides a continuous crystal free stream over the SSHEs where small ice crystals (nuclei) are formed and pumped into the...

Health Hazards Associated With General Industry A Chemical Agents

Chemical agents such as solvents or hydrocarbons may have multiple effects on many different body systems. Solvents are ubiquitous at hazardous waste sites therefore, there is a good chance that workers handling hazardous waste will be exposed to one or more solvents. For many of these agents, the adverse effect is seen relatively soon, so the cause of the effect is identifiable with some carcinogenic agents that may cause cancer years later, the link between the agent and the disease is less...

Secondary Treatment Biological

Physical treatment of raw municipal wastewater by sedimentation removes most of those pollutants that will either float or settle out by gravity, which accounts for only approximately 35 of the BOD. The major purpose of secondary treatment is to remove nonsettleable (colloidal and dissolved) solids in the wastewater. Secondary treatment is generally considered to mean at least 85 efficiency in reducing BOD and now represents the minimum degree of treatment required by law in most cases. Some of...

PH Measurement

PH is a unit of measure that describes the degree of acidity or alkalinity of a solution. The origin of the terminology comes from the letter p, meaning power, and the letter H symbolizing hydrogen 1 . Formally defined, pH is the negative logarithm of the hydrogen ion activity Since pH is a logarithmic function, a change of one pH unit represents a tenfold change in hydrogen ion concentration. Figure 1 includes a table correlating pH to the hydrogen ion and hydroxyl ion concentrations, H + and...

Contributors

Aly Utah State University, Logan, Utah E. J. Anthony CANMET, Ottawa, Canada Milovan S. Beljin University of Cincinnati, Cincinnati, Ohio Douglas M. Brown The Logistics Management Institute, Bethesda, Maryland M. S. Chandrasekharaiah Houston Advanced Research Center, The Woodlands, Texas Allen P. Davis University of Maryland, College Park, Maryland Steven K. Dentel University of Delaware, Newark, Delaware Merrit P. Drucker Army Management Staff College, Fort Belvoir, Virginia Jeffrey C....

Recycling

Recycling via use and or reuse involves either returning a waste material to the originating process as a substitute for an input material or using it in another process as an input material. Return to original process Raw material substitution for another process Example Reuse Return to Original Process. A printer of newspaper advertising purchased an ink recycling unit to produce black newspaper ink from its various waste inks. The unit blends different colors of waste ink together with fresh...

Applications

The observation that a number of solute species present in the solution were photocatalyzed at the illuminated semiconductor surface evolved from the photodecomposition studies of water with solar radiation. Bard and coworkers 26-30 have shown that many hazardous species, including some of the EPA priority pollutants, could be degraded into innocuous species at the illuminated titania semiconductor surface. Their work formed the nucleus for the concept of photocatalytic degradation of hazardous...

Debra J Trantolo

Massachusetts Library of Congress Cataloging-m-Publication Data Process engineering for pollution control and waste minimization edited by Donald L. Wise, Debra J. Trantolo. p. cm. -- (Environmental science and pollution control 7) Includes bibliographical references and index. ISBN 0-8247-9161-4 (alk. paper) 1. pollution. 2. Waste minimization. I. Wise, Donald L. (Donald Lee). II. Trantolo, Debra J. III. Series. TD191.5.P76 1994 The publisher offers discounts...

Multiple Extraction Procedure

The standard extraction tests (TCLP or California STLC) provide a one-time equilibrium solubility value of the heavy metal compounds in the extraction fluid but do not give an indication of the time-dependent stability of the residual matrix. The EPA multiple extraction procedure, designed for evaluating the leachability of materials exposed to so-called acid rain conditions, was used to test the stability of the polysilicate cementitious treatment protocol. Table 3 Effect of Particle Size on...

Example Management Programs

The Los Alamos National Laboratory is a research facility operated by the University of California for the U.S. Department of Energy. Since its inception in 1942, the laboratory has handled a variety of hazardous materials, including compressed gases. In 1990 a facility-wide program was undertaken to manage compressed gases considered to be in excess of their users' requirements. The objective of the program was to identify and properly manage cylinders containing compressed gases. The need for...

Kinetics

The initial photocatalytic reaction rate follows a Langmuir-Hinshelwood type of relationship with respect to initial organic concentration where CQ is the initial concentration of the target organic compound. The constants k and K represent collections of oxidation, recombination, and possibly adsorption terms. This expression describes a first-order reaction at low substrate concentrations, with a transition to a rate independent of organic concentration at high substrate loadings (Figure 2)....

Dairy Plant Wastes

Dairy wastes are generally dilutions of milk or milk products resulting from product losses during handling and transport together with detergents and sanitizers from intensive washing operations. The following operations contribute to the major product losses 3 1. Sludge discharges from clean-in-place (CIP) clarifiers 2. Start-up, shutdown, and changeover in high temperature, short time (HTST) pasteurizers 5. Tank, can, piping, and other equipment washing 6. Breakage and spillage in packaging...

For Contaminated Sites

Funk, Ronald G. Fender, and Marilyn Hewitt Environmental Resources Management Group Exton, Pennsylvania I. CHARACTERISTICS OF ENVIRONMENTAL CONTAMINANTS There are literally thousands of substances that can contaminate the environment. In some cases, this contamination is related to natural conditions and is thus a background condition. Most often, however, environmental contaminants are related to human activity. Current regulatory programs governing contaminated sites...

Aerobic Biological Treatment

Tabulated information on a wide range of activated sludge plants, both laboratory and industrial units, treating dairy wastewater is available elsewhere 8 . The treatment efficiency values vary from about 25 to over 99 with an average removal efficiency of about 85 . With good operation, BOD removal efficiencies in excess of 90 are easily attainable with activated sludge systems however, even an efficient system may not be able to reduce the BOD from 2000 mg L in the dairy waste to 20-30 mg L...

ORP and pH Measurement

To apply the chemistry discussed in Section II to an automated process, it is critical to control the pH and the oxidation reduction potential (ORP). The adjustment of the pH and the ORP is achieved with electrodes in combination with millivolt controllers and chemical feed pumps. The electrode system for pH determination consists of a glass electrode and a reference electrode. The most common reference electrode is the saturated calomel electrode Hg Hg2Cl2 KCl(sat) with a constant potential of...

Mechanisms and Intermediates

As a result of the current interest and investigative activity into various aspects of the PCO process, some consistent mechanisms of oxidation are beginning to emerge, although many conflicting ideas are still ubiquitous. As noted, PCO demonstrates a Langmuir-Hinshelwood relationship with respect to organic substrate concentration Equation (11) . It has been assumed that this dependence was directly due to a Langmuir isotherm dependence of the substrate adsorption. For example, Matthews 56...

Identification Of Cylinder Contents

Where identification of a compressed gas is necessary, safety of the sampling effort becomes a critical concern. Because of the chemical characteristics of some gases, fire or explosion or other release of toxic gas may occur during sampling. When cylinders or valves have deteriorated, it is very possible to have failures resulting in uncontrolled release of the contents. Procedures and technologies that have historically been used for management of cylinders in poor condition have not always...

Assumptions Underlying the Shift to Pollution Prevention and Green Design

Much of the environment legislation enacted in the 1970s and 1980s was media-specific that is, each statute focused on either emissions to air, discharges to water, or disposal on land. This approach arose from a general consensus that industry should be in charge of deciding how to manufacture its products. The government's role was is to protect human health and the environment and therefore should be limited to regulating emissions, discharges, and wastes after they leave the manufacturing...

Municipal Solid Waste

A municipal solid waste disposal management system may include any combination of sanitary landfill, energy production, and recycling. Historically the collection and transportation of MSW accounts for 75 of the total cost of the waste management system. Landfill1 costs are increasing dramatically as more stringent standards are imposed. Further, the cost of transportation of waste is increasing dramatically as large cities run out of landfill space and the will to site new landfills and, as a...

Top Seals Cap or Cover Barrier Layers

Top seals (i.e., surface seals, caps, covers), as shown in Figure 10, function to control surface water so as to minimize infiltration, maximize runoff, prevent direct contact (such as by burrowing animals, which may dig into the landfill areas), and thereby reduce leachate production Figure 9 Schematic drawing of a vibrating-beam slurry wall. (1) Top seal (2) landfill material (3) bottom seal. Figure 9 Schematic drawing of a vibrating-beam slurry wall. (1) Top seal (2) landfill material (3)...

Processes of Decomposition of Refuse in Landfills

Landfilled material will gradually change in form and will exhibit different engineering and physical properties as a result of various environmental factors. Witmer and coworkers 7,8 reported the garbage decomposition process for a 10-year period as reflected on a particle size distribution curve. The aging process from fresh trash to aged trash along with the environmental and mechanical factors are illustrated in Figure 1. Mechanical processes do not directly contribute to the decomposition...

Ecological Limitations And Solutions

The technology of environmental bioremediation depends on ecological investigations of bacterial metabolic diversity. However, research on ecological approaches to solving problems that may arise during in situ bioremediation has focused on ecological risk assessment of the en- Table 3 Genetic Limitations and Potential Solutions in Environmental Bioremediation Heterogeneous chemicals requiring diverse degradative operons absent from contaminated site Biodegradative genes present but rate of...

Cyanide Oxidation

Cyanide (CN )-based plating baths exhibit the unique property of producing fine crystalline, shiny metal coatings. They are therefore widely in use despite the high toxicity of cyanide and the greater control effort necessary in pretreatment. Cyanide destruction is commonly achieved through oxidation in the alkaline region using chlorine gas or sodium hypochlorite. Peroxide oxidation and treatment with ozone are reported to be feasible. Electrolytic oxidation has advantages in treating highly...

Primary Treatment

Wastewater contains suspended matter that has a higher specific gravity than the liquid and is in a relatively quiescent state, the particles will settle out because of gravity. Grit chambers remove grit, including gravel, sand, and heavy particulate matter such as corn kernels, bone chips, coffee grounds, and broken glass. All of this accounts for only a portion of the inert suspended solids in raw sewage. After grit removal, the wastewater still contains suspended solids, which are then...

Column Leach Test Description

When hydrocarbon-contaminated soil that has been treated by the Siallon process is analyzed, the appropriate total concentration analysis is used. These methods will generally involve solvent extraction followed by gas chromatographic analysis, which gives a result that is indicative of the sample as it stands or at a fixed point in time. To assess the effects of both time and groundwater intrusion on Siallon-treated soils an extensive leachability study was undertaken. The study involved more...

State Pollution Prevention Contacts

Alabama Hazardous Waste Division HAMMARR 241 Mineral Ind. Bldg University of Alabama P.O. Drawer G Tuscaloosa, AL 34587-9644 (205) 348-4878 Pollution Prevention Program Department of Environmental Conservation Toxic Substances Control Program Department of Health Services Alternative Technology Division Juneau, AK 99811-1800 (907) 465-2671 P.O. Box 942732 Sacramento, CA 94234-7320 (916) 322-2822 Alaska Health Project 431 W. 7th, Suite 101 Anchorage, AK 99501 (907) 276-2864 Waste Minimization...

Schedule of Leaching

Each cavern is developed through two phases of leaching. These phases are engineered to provide a cylindrical cavern at the completion of the solution mining. The development program is the same for each cavern and requires about 340 leaching days to complete. Variations in the salt body may require changes in the duration of each leaching phase and modifications of the leaching plan. Phase I consists of about 240 days of solution mining by the direct-injection method. This phase provides for...

Introduction

Melt crystallization is a standard chemical industries purification process for chemical products such as naphthalene, para-xylene, dichlorobenzene, acrylic acid, monochloroacetic acid, bisphenol A, and others 1 . It is seen as an extremely selective separation process that can reduce contaminant levels to the ppm range. This provides an effective means to purify some products. Freeze concentration (FC) is usually associated with the process when the crystallizing component is water. In this...

Metal Sulfide Precipitation

The solubility products of metal sulfides are several orders of magnitude lower than those of the corresponding hydroxides. This should make it feasible to precipitate the heavy metals from solutions containing complexing agents that prevent metal removal by hydroxide precipitation. Also, the pH range for the precipitation of metals as sulfides is much broader. Table 3 lists the solubility products for metal sulfides of the type MeS, Me2S, and Me2S3 15 . Metal sulfide precipitation occurs if...

Green Product Design

Several years after the surge of pollution prevention programs, a growing number of companies have looked to a more expanded view of pollution prevention green product design. These companies are finding that green products products that reduce the burden on the environment during use and disposal have additional marketing appeal to consumers. In contrast to past practices, in which product performance and environmental compatibility were managed at different points in the production process,...

References

L., and Razbin, V. V., Preliminary Report on Combustion Trials of a Pelletized Paper Product in a Pilot-Scale Fluidized Bed Combustor, ERL Division Rep. ERP ERL 84-02(Int), August 1984. 2. Gendreau, R. J., and Raymond, D. L., An assessment of waste fuel burning in operating circulating fluidized bed boilers, AIChE Natl. Meeting, New Orleans, La., April 6-10, 1986. 3. Preto, F., Anthony, E. J., Desai, D. L., and Friedrich, F. D., Combustion of rice hulls in a...

Regulatory Considerations

The management of waste compressed gas cylinders is governed by federal, state, and local regulations. Federal regulations apply to the interstate movement and filling of cylinders. Hazardous waste management and air pollution regulations may be applicable. Local building and fire codes also apply to cylinder use and storage. Federal Department of Transportation (DOT) regulations govern the transportation and refilling of compressed gas cylinders. Under these regulations (found in 49 CFR),...

Air Stripping

Air stripping of groundwater may expose workers to hydrocarbons when work is carried out in the vicinity of the effluent. There are several potential exposure points, including sampling points, leakage from lines, monitoring wells, the insides of vessels during maintenance, and effluent vents. The design of sparging wells should include assurances that the extraction well pressure will always be less than that of the injected air well. If the extraction line includes a dilution port, a check...

Titanium Dioxide Surface Reactions

Titanium dioxide is rapidly hydrated in aqueous solution due to the partially uncoordinated states of its surface titanium and oxygen atoms. The amphoteric nature of the hydrated Ti02 surface results in pH-dependent equilibrium between protonated and deprotonated hydrous surface species 11 , I I where represents the bulk solid. The pH at which the overall Ti02 surface is neutrally charged is termed the zero point of charge or pHzpc. Reported values of the pHzpc for Ti02 range from 3.5 to 6.7...

Summary of Key Federal Environmental Statutes Enacted Since 19701

In 1970, Congress established the U.S. Environmental Protection Agency (EPA) with the enactment of the Reorganization Act of 1970. This act consolidated the various environmental management responsibilities that were previously dispersed throughout the executive branch agencies, for example, Department of Interior (federal land management, mining), the Department of Agriculture (pesticide registration), and the Federal Water Pollution Control Administration (development of scientific and...

Bottom Seals Liners

Barriers And Liners

In new waste containment facilities, it is usually necessary to provide a liner system beneath the waste disposal area. The major function of a liner is to prevent leachate or waste from migrating downward and entering the groundwater flow regime. The barrier layer for liner systems can consist of native clays, processed clays, or geosynthetic membranes as previously discussed for covers. It is important to note that under the present U.S. regulations, the use of a synthetic membrane liner is...

Lime Types Uses Composition And Treatment

Lime Schematic Diagram

Acidic industrial wastewater can be neutralized with slaked lime Ca(OH)2 , caustic soda (NaOH), or soda ash (Na2C03). Since slaked lime is less expensive than other bases, it is the most commonly used chemical for acidic neutralization 5 . Two types of commercial lime with their associated hydrates are high calcium quicklime, otherwise known as calcium oxide (CaO), and dolomitic quicklime (CaO and MgO). The composition of these will depend on the source of the parent limestone and the method of...

Cavernleaching Techniques

The fundamental technique of cavern development involves drilling and cementing concentric casings into the salt dome, then drilling an uncased hole to expose the salt for dissolution. Two concentric leaching strings of pipe provide circulation of water through the well to dissolve the salt (Figure 7). Water is injected through either the inner leach string or the annulus, depending upon the leach phase. As water is injected and cavern development proceeds, a flow of brine is circulated back to...

Chemical Solidification And Stabilization Processes

Chemical solidification and stabilization processes are used to treat industrial and hazardous wastes. These processes represent alternatives to ocean disposal or conventional landfilling. Most of these processes originated in the field of radioactive waste control and management. Chemical solidification and stabilization refer to waste treatment that results in the combined effect of 1. Improvement of physical properties (mechanical stabilization) 2. Encapsulation of pollutants (immobilization...

Reuse Of Petroleumcontaminated Soils In Concrete Production

An experimental investigation designed to evaluate the effectiveness of using petroleum-contaminated soils (PCS) as fine aggregate replacement in concrete was conducted at Stevens Institute of Technology. The details of the experimental program and the resulting findings are Table 6 Research on Stabilization using Pozzolanic Binders Class C ash, lime, and cement mixtures with Class F ash Fly ash, lime Portland cement, fly ash, calcium sulfate dihy-drate, lime, recycled rubber, asphaltene,...

Oxidation of Organic Compounds

The complete degradation of chloroform (CHC13) to carbon dioxide, water, and chloride ions has been demonstrated by Pruden and Ollis 27 using Ti02. A decrease in chloroform, along with formation of carbon dioxide and chloride, was found according to the stoichiometry CHCI3 + H20 + 0.5 02 -> C02 + 3 HC1 (9) Continued work by the same researchers has examined the mineralization of several simple chlorocarbon solvents and acids 26,28,31,32 complete degradation of these reactants to inorganic...

Pollution Prevention Programs

Pollution prevention is often discussed within the context of a widely accepted notion of a waste management hierarchy. The waste management hierarchy places the highest priority on reducing waste at the source of generation through the use of less toxic raw materials, equipment changes, process redesign, and better housekeeping and materials management. The second preference in the hierarchy is reuse and recycling of wastes that cannot be reduced at the source. The third preference in the...

Siallon Applications And Mixing Equipment

The Siallon microencapsulation process is applicable to the treatment of a wide variety of waste materials. The hydrocarbons that have been successfully treated and found to be amenable to treatment by microencapsulation include crude oil, gasoline, coal tars, creosote, lubricants, diesel fuel, jet fuel, PCBs, and refinery wastes. The differences between many types of wastes are related not so much to the type of contaminant as to the physical form of the waste matrix. The treatments of pure...

The Siallon Process A Overview

The chemistry of the patented 12 Siallon process is simple in that it is a two-stage reaction involving two water-based products. The first step uses a water-based emulsifier that first desorbs the hydrocarbon from the soil and then emulsifies it within a water phase. The second stage is the addition of the Siallon reactive silicate solution to the mixture of soil and emulsified hydrocarbon. The silicate undergoes an acid-base reaction with the emulsifier micelle and is neutralized, forming a...

Barrier Walls

Sketch Bentonite Slurry

The control of contaminant migration from existing disposal sites or impoundments may necessitate a vertical subsurface barrier to horizontal groundwater flow. Barriers commonly constructed include soil-bentonite slurry trench cutoff walls and cement-bentonite slurry trench cutoff walls. Vibrating beam cutoff walls, grout curtains, sheet piling, and composite walls are also used. For vertical barrier walls to be effective, they are generally keyed into an impermeable stratum of natural...

Treat the Task Seriously

Success in the elimination of pollution depends on the effective efforts of all employees. If environmental issues are viewed as solely the responsibility of an environmental department or if input to production process modifications are provided solely by process engineers, the needed commitment from other departments may not be achieved. Further, if the firm fails to maximize its use of available information, it may miss important insights. To a large extent, the degree to which individuals...