Pollution Prevention Chapter 7 PDF

CHAPTER 7 Pollution Prevention 7-1 GENERAL CONSIDERATIONS EPA suggested the following hierarchy for management of wastes: - The term waste minimization applies to any management technique or process modification that ultimately reduces the...

CHAPTER 7 Pollution Prevention 7-1 GENERAL CONSIDERATIONS EPA suggested the following hierarchy for management of wastes: - The term waste minimization applies to any management technique or process modification that ultimately reduces the mass, volume or toxicity of waste sent to treatment and disposal facilities. Hazardous regulation and associated liabilities cause all industries to develop means and measures for reducing hazardous waste generation. An overview of waste minimization, or pollution prevention (P2) techniques 1  Pollution Prevention (P2) – INCENTIVES 1. Economic Incentives It is common practice today to think of wa$tes simply as resources out of place. An important aspect in evaluating the economics of environmentally desirable process is to examine the "big picture" as illustrated in Figure 7-2. 2  2. Legal and Regulatory Incentives - A second motivation for conducting waste minimization evaluations in the US is that they are required by law. - Another legal incentive is the potential future liability for any hazardous wastes produced can be avoided. 3. Public Demands - Another important incentive is that the public will no longer tolerate the continued production of hazardous waste. - This intolerance manifests itself in many forms, including the new legislation, and consumer boycotts of products from companies perceived not to be environmentally responsible. 7.2 MANAGEMENT STRATEGIES Overview The goal of minimizing the generation of hazardous waste at a manufacturing facility, how does one proceed? 3 4  The following outline (See Figure 7-3) is suggested: 1. Planning and organization 2. Characterization of wastes and losses 3. Development of waste minimization options 4. Technical, regulatory, and economic feasibility 5. Implementation (including training) 6. Monitoring and optimization 7. Continued and ongoing evaluations of a reaching a “zero” generation”. Waste minimization audit The waste minimization audit consists of planning the entire program and fully characterizing all wastes. Planning includes: - obtaining commitment of top management, budgeting financial and human resources - setting goals and establishing incentives and communicating the policy and goals to facility employees - designating a person to lead the program and organizing a team to support it - Preparing schedules, worksheets, and other necessary tools. The waste minimization audit includes a thorough survey to provide the following data for each hazardous waste stream:  Specific sources  Physical and Chemical characteristics  Production rate of process  Operation- generating the waste  Current management methods from generation to final disposition  Cost of each management method 5  Necessary sources of information to complete this include: - Process flow diagrams - Material and heat balances (both design and actual) - Operating manuals and process descriptions - Equipment lists, Equipment specification and data sheets - Piping and instrument diagrams Other supporting sources of information include: o Material safety data sheets, MSDS o Material purchase records o Product and raw material inventory records o Production records o Operator data logs and Operating procedures o Maintenance procedures and Maintenance records Any proposed alternative must be evaluated in terms of its technical, regulatory, and economic feasibility. Pollution Prevention Methods Four stages of waste reduction: 1. Commonsense sense waste reduction-immediate opportunities (i.e. reduce amount of water use) 2. Information driven waste reduction (i.e. replacing organic solvent) 3. R & D based waste reduction 4. Audit dependent waste reduction Perhaps the simplest waste minimization efforts involve Housekeeping changes: - Segregating hazardous waste - Training employees. - Sweeping floors prior to washing 6 Production changes: - Changes in process operating variables (e.g., temperature, pressure) - Changes in raw materials - New process chemistry - Equipment changes - Product elimination Microeconomic Analysis It must be recognized that pollution prevention projects must compete with other proposed capital projects for company funds. In order to fully appreciate the actual cost of a new waste minimization equipment, it is necessary to look at the savings resulting from reduced cost of waste disposal. 7-3 LIFE CYCLE ANALYSIS Life cycle analysis (LCA): A systematic approach for identifying and evaluating opportunities to improve the environmental performance of industrial activity in all stages of a product. By employing LCA methods, corporations are identifying opportunities to reduce environmental impacts, while maintaining or gaining competitive advantage. 7  Product Life Cycle Example: The typical car contains about 180 pounds of plastic. However, when a car is disposed of, the different plastics in the car cannot be easily sorted. To counter this life cycle problem, BMW introduced a new series of small cars in June 1992. Plastic parts are stamped by type during fabrication so they can be sorted quickly and accurately. In addition, the cars are designed for disassembly. Design for disassembly is one of the many life cycle techniques being embraced by the auto and other industries. 8 Performing LCA within Industry One common approach being used in industry to perform LCA is outlined in Table 7-5. Inventory Phase - Organize LCA team - Target products/processes for LCA Targets (e.g., product A, process B, and/or activity C) - Diagram the life cycle: Identify input and output  The location of waste (e.g., a process vent, wastewater stream, etc.),  The type (e.g., air emissions, wastewater, and solid or hazardous waste)  The amount of material or waste transferred (and/or energy utilized). 9 Impact (Interpretation) Phase, After the inventory  Interpret the impacts of waste emissions and energy usage.  Review of regulated chemicals, wastes, emission, etc.  Review of non-regulated targets. Corporations can promote the EHS performance by setting priorities beyond compliance, either expanding efforts beyond regulated materials, wastes, and processes. Improvement Phase The improvement analysis: - Identification of improvement options, followed by - a comparative evaluation which requires a comparison of the technical, economic, and regulatory feasibility of each option. - Compliance alternatives: Compliance with even the most stringent regulatory or corporate requirements can often be achieved by using different strategies and technologies. 10  CASE STUDY 1: EVALUATING PACKAGING DESIGNS In the following simplified example (Table 7-6), an LCA was conducted on various packaging alternatives for a liquid fabric softener. Only four of the several possible alternatives were studied. The data are based on 1000 liters of a single-strength product. The table indicates percent decreases for each energy and emission category as compared to a non-recycled 64-ounce bottle made of virgin high-density polyethylene (HDPE). 11 7.4 VOLUME REDUCTION An appropriate place to initiate waste minimization investigations is to examine ways to reduce the volume of hazardous waste. This can be accomplished by: (A) Modifying production processes, (B) Segregation, and (C) Reuse. (A) Process Modifications Process modifications include changes in: - Raw materials o Raw material substitution: Raw material substitution includes such simple items as cleaning materials. o Sometimes conversion to a higher quality raw material can eliminate the generation of hazardous waste. - Equipment Production supervisors must be committed not only to the changes in equipment, but also to training staff as to the reasons for the changes. - Operating procedures - Materials storage - End products (B) Segregation - Avoid mixing wastes. Major obstacles to waste segregation programs are materials that go into trash but don't belong there. - Keeping non-contact cooling water separate from waste streams. - Don't make it a liquid if it is dry! Housekeeping operations as simple as sweeping prior to washing floors can substantially reduce waste volumes. - Some solid waste streams can be segregated effectively through minor changes in equipment. 12 (C) Reuse - Many materials that are disposed of as hazardous waste have a potential to be reclaimed for another application. In some instances, contaminated materials may be of adequate quality to serve as a solvent or cleaning material for a less sensitive application. - Another source of hazardous wastes is raw materials stored past their expiration date. Such dates are often established conservatively and it may be possible to re-qualify the material for use in production. 7-5. TOXICITY REDUCTION A number of waste minimization techniques reduce the concentration of contaminant in a liquid or solid waste stream. It is often possible to lessen the toxic characteristics sufficiently so that the remaining waste is no longer considered a hazardous waste. Process Modification Example: Powder coating technology has reduced the need for solvent-based paints in many industrial painting applications. Equipment Modification As in the discussion of volume reduction, many pieces of equipment can be modified to reduce waste characteristics. Example: Where small quantities of powdered chemicals are used, it is common practice to purchase these materials in 50-pound bags. Initially an operator would simply cut the bags open and dump the powder into a hopper. Health and safety concerns subsequently required that the operating area where the bags are cut and dumped be properly ventilated to protect workers. Then air pollution control equipment in the form of a wet venturi scrubber was added to the ventilating system to avoid violating air pollution laws. This resulted in a liquid hazardous waste (the spent scrubber solution) being produced. 13 Solution: The installation of a small packaged bag dumping station, where bags are placed in a sealed contained box and then cut open eliminates a major waste source and a lot of unneeded equipment. What is required is a new look at the equipment!!! Housekeeping Practices Perhaps the simplest and most inexpensive method of reducing hazardous wastes at the source is through revision of housekeeping and maintenance procedures. Examples: - The design of storage areas should allow for easy inspection of potential sources of leaks. - Training must be a major element of housekeeping practices. - Soliciting waste minimization suggestions from operating staff. Employees should be encouraged to suggest additional practices that will further reduce waste generation. - Labeling is a simple housekeeping task that can markedly reduce the generation of hazardous waste. - A check on housekeeping practices should be part of routine inspections of the operating units. 14 Material Substitution The changing economics of waste management are forcing a new look at production formulations. Example: Industries producing machine parts use large quantities of lubricating oils that become contaminated with metals and must be disposed of as a hazardous waste. Synthetic lube oils cost more but last longer than petroleum-based materials, which can be returned to the manufacturer for recycling. 7-6 RECYCLING - When it is not possible to reduce the volume or toxicity of a waste, it may be possible to recycle it to another process or another plant. - Onsite recycling is preferable because shipping hazardous waste off-site, even for recycling, carries the liability that the waste might be mishandled. Water - Water is the easiest material to recycle. It is often possible to recycle process water to a less sensitive use. - Another potential source of recycle water is non-contact cooling water. Often such water is simply discharged as a heated but uncontaminated waste stream. - In the instance of an extremely acidic line, neutralization with caustic is an obvious solution. Solvents Solvent recycling is common practice in many industries, and a wide range of solvents are recycled. Some of the common solvents currently being recycled are shown in Table 7-8. 15   Another effective way to recycle solvents is cascade reuse, where a solvent is used once for high-quality cleaning and then for other operations that can perform effectively with a less-pure solvent. The subsequent operation may occur at the same plant or involve shipping to another company.  An example would be solvents used in highly demanding pharmaceutical operations that are reused directly in metal product manufacturing. Oil Oil that has become contaminated with hazardous materials may require disposal as a hazardous waste. Often this can be recycled rather than shipped for off-site disposal. The energy content of spent oil can be reclaimed in many instances, through burning in industrial boilers or furnaces. Solids A wide range of solid materials, including paper, metals, and plastics, are amenable to recycling. The recycling of paper and paperboard has become routine at most industries. Scrap metal is also a common candidate for recycling. 16 Waste Exchanges - While reusing a waste product inside a manufacturing facility is desirable , it is not always possible to find another department or process that can effectively utilize the waste. - An alternative is to locate another company that can make use of your waste. A waste exchange is a regional clearinghouse for such transactions. - Waste exchanges maintain computer databases and/or lists of wastes available or materials sought by various industries. For more info: General Info: http://www.epa.gov/p2/ Pollution Prevention: https://www.youtube.com/watch?v=RQqCksp6kDY LCA: https://www.youtube.com/watch?v=6RNnzfUHwY8 17