In the Classroom edited by
Safety Tips
Timothy D. Champion Johnson C. Smith University Charlotte, NC 28216
Pollution Prevention Guideline for Academic Laboratories Edwin Li and Stanley M. Barnett Chemical Engineering Department, University of Rhode Island, Kingston, RI 02881;
[email protected] Barbara Ray Safety and Risk Management Department, University of Rhode Island, Kingston, RI 02881
Many classroom laboratory experiments were designed focusing on the learning objectives and not on the safety aspects of the experiment. Therefore, many of these experiments unnecessarily generate large quantities of wastes that must be properly handled and disposed of. This article presents a methodology to evaluate alternatives to eliminate or reduce the generation of laboratory chemical and biological waste. A guideline has been designed to enable schools to reexamine current laboratory practices (educational and research) and evaluate different approaches that can be used to eliminate or reduce waste generation. The first part of the guideline is a brief description of pollution prevention and several approaches to accomplish it. It includes a few recent references of new and modified experiments, suitable for instructional laboratories that can be used as alternatives for pollution prevention. The second part is a step-by-step methodology intended to aid instructors in the selection of practices that eliminate or minimize the generation of waste. The methodology presented is just that—a methodology. It is the responsibility of the department safety committee and instructor to evaluate the relevant factors (safety practices, learning objectives, federal, state, and local regulations, school policies, etc.) and determine how these factors should be considered in evaluating the various alternatives. Pollution Prevention The EPA defines pollution prevention in the Pollution Prevention Act of 1990 to include practices that prevent or reduce pollution at its source (1). Pollution prevention also includes practices that reduce or eliminate the creation of pollutants through increased efficiency in the use of raw materials, energy, water, or other resources, or protection of natural resources by conservation. Pollution prevention practices and techniques often reduce overall operational and environmental-compliance costs. By preventing the generation of waste, pollution prevention reduces disposal costs and reduces long-term liabilities and cleanup costs associated with the improper disposal of wastes. Pollution prevention can also reduce teacher and student exposure to hazardous materials and reduce waste disposal storage requirements. Furthermore, by preventing pollution there will be a greater likelihood that the facility will be in compliance with local, state, and federal statutes. Finally, schools have the dual responsibility of protecting the environment as well as preparing students for working in the real world. The preferred pollution prevention approach is to reduce the amount of waste generated. This approach, referred
to as source elimination or reduction, is the cornerstone of pollution prevention. When source reduction is not possible the next option is recycling, refining, or recovering the byproducts for reuse. This approach minimizes the use of raw materials and the disposal of waste to the land, water, or atmosphere. The third alternative is to treat the by-products (prior to declaring it waste) to make it less hazardous for disposal. If none of the first three methods are applicable, proper disposal of chemical or biological waste is required. Disposal of hazardous wastes must be performed in compliance with applicable (federal, state, and local) regulations. The pollution prevention hierarchy of preferred options, as established by the EPA and described above, is summarized in Figure 1.
Source Elimination or Reduction Source elimination or reduction allows for the greatest and quickest improvements in environmental protection by avoiding and reducing the generation of waste and harmful emissions, and may reduce the toxicity of any waste that is produced. Source elimination or reduction methods for laboratory experiments include chemical substitution and microscale experiments. Other approaches include computer simulations and better management of chemicals (inventory management or centralized chemical purchasing). Chemical substitution involves substitution of hazardous chemicals with nonhazardous (or less hazardous) chemicals. Substitution can sometimes be performed in conjunction with scaling down approaches. Traditional educational experiments are designed at a macroscale level. Most of these experiments can be scaled down and still achieve the same learning objective(s). The benefits include less waste, reduced exposure to chemicals,
Source Elimination or Reduction
Recycling or Reuse
Treatment
Disposal Figure 1. Pollution prevention hierarchy.
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reduced chemicals consumed in the experiment, and reduced costs of chemical purchases and waste disposal. Microscaling, in upper-level chemistry classes, and even in chemical engineering courses, complements the use of analytical equipment (chromatographs, spectrophotometers, NMR, etc.). These systems, by design, require extremely small sample quantities for analysis. Investment in specialty laboratory equipment (microscale kits, capillary melting point apparatus, electronic digital balances, micropipets, and syringes, etc.) pays for itself in a short time. If microscaling is not possible, consider decreasing the experimental quantities by one-third or one-half. Recent articles on microscaling applicable to academic laboratories include those of Arnáiz and Pedrosa (2), Mahamulkar et al. (3), and Montaña and Grima (4). In a teaching laboratory, some of the following alternatives may be considered to eliminate or reduce the use of chemicals: computer simulation or video demonstration of experiments, students working in teams, and demonstration of experiments by the instructor instead of having the class perform them. Some practical in-class demonstrations can be found in this Journal. These demonstrations cover a wide range of topics in chemistry (5–7). A comprehensive chemical inventory is necessary to effectively manage chemical usage. Chemical inventories prevent purchasing chemicals already in stock and allow laboratory personnel to know exactly what chemicals they have, how much is available, and where the chemicals are stored. An effective chemical inventory will also reduce waste generation by tracking shelf-life dates (ensuring chemicals are used prior to expiration), reallocating chemicals to laboratories where they will be used, and eliminating the purchase of bulk chemicals to obtain purchase discounts. The chemical disposal costs should always be considered when purchasing any chemical. The quantity obtained should be limited to the amount of the immediate need. Chemicals are often ordered in quantities above the current need to obtain quantity purchase discounts. The unused quantity is then discarded as a waste with the disposal cost often significantly greater than the purchase savings. Often the disposal costs are not considered because they may be paid by an administrative unit rather than by the waste generator. A comprehensive and current chemical inventory will allow laboratory personnel to identify chemicals that can be reallocated (chemical redistribution) prior to purchasing new materials and chemicals that are approaching their expiration dates. Updating the inventory periodically is necessary to ensure it is useful and accurate. The surplus chemicals can be made available for use by other laboratories.
Recycling or Reuse Redistribution of chemicals minimizes waste and provides more space for storage. Proper chemical management includes periodic updating of the chemical inventory. Chemical inventory review will identify chemicals that are not being used in the laboratories, as well as where they are stored, and can be made available for use by other laboratories. Solvent recovery by distillation and reuse should be considered. Many solvents, including xylene, methanol, acetone, and toluene, are excellent candidates for recovery by distillation. Notable exceptions are peroxide-forming solvents, which 46
should not be distilled. Care should be taken in establishing a solvent recovery program to ensure that appropriate segregation of solvents and regulatory considerations (flammable material handling and storage, as well as hazardous waste) are included in evaluation of any solvent-recovery operations. Chemical recovery can be incorporated into the laboratory teaching objectives. The process can be incorporated as the final step of a chemistry or unit operations experiment, or can be an extra-credit opportunity for interested students. (Caution: Recovery methods should always be performed under supervision.)
Treatment Technically, treatment is not waste minimization, and should only be considered after evaluation of other alternatives. Treatment generally applies to efforts to make experimental by-products less hazardous before they are declared as wastes for disposal. Neutralization of acids and bases is the most common method of treatment. It involves the reduction of a material’s corrosivity (acidic or caustic properties) by raising or lowering the pH to a neutral range, between 6 and 9 standard units. Other types of treatment may be used (separation, fixation, oxidation, precipitation, degradation, ion exchange); however, once the material has been designated a hazardous waste, treatment must be in conformance with applicable regulatory requirements. Treatment can also be incorporated into the laboratory teaching objectives. The process can be incorporated as the final step of a chemistry experiment, or can be an extra-credit opportunity for interested students. An example of this approach is illustrated by Nash et al. (8). Other examples may also be found doing a search in the JCE Online index. Disposal Accurate identification and classification is the first step in proper handling and disposal of laboratory waste. Correct identification allows the waste to be properly segregated and stored. This step makes handling the waste safer and may make disposal less expensive. Proper identification is therefore the first step in efficient waste management. The EPA requires that all waste generators, including laboratories, determine whether materials are hazardous waste: either as listed waste or characteristic waste. Listed wastes are by-products of specific processes listed in 40 CFR 261 (9). Characteristic wastes exhibit hazardous characteristics of either ignitability, corrosivity, reactivity, or toxicity as defined in 40 CFR 261. Laboratory Pollution Prevention Methodology The goal of the methodology is to assist in the selection of a pollution prevention alternative for a specific laboratory practice. Selection of the best alternative is achieved after careful planning, screening, and testing of approaches that will eliminate or minimize waste generation by quantity or toxicity. The proposed laboratory methodology is outlined in Figure 2.
Planning and Organization Proper planning and organization is arguably the most important step in effectively implementing a pollution prevention evaluation. The same is true for implementing this
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laboratory pollution prevention methodology. Planning and organization includes selecting the team members, defining objectives, and establishing a timeline. The project team needs to be knowledgeable of the following: learning objectives of the laboratory experiment, regulatory requirements for proper raw-material and wastematerial handling, school policies and procedures for proper raw- and waste-material handling, raw- and waste-material costs, laboratory equipment availability and costs for purchase of equipment, and management’s (department or administration) focus. The project team may consist of the following members: department chair, professors, teaching assistants, provost or dean, and staff members from the health and safety, facilities, and finance offices of the school. The project team may consist of two or more individuals. The team members may depend on the laboratory practice or course to be examined. However, in order to be successful the individual(s) must understand the various elements and must have been empowered by management to undertake this evaluation. The project team must have clearly defined objectives. Establishing definitive objectives will ensure the project team has been properly staffed with a clear understanding of the goals to be accomplished in the established timeline.
Develop Evaluation Criteria The next step is to develop the evaluation criteria for the various alternatives. These criteria will be used to assess possible alternatives and select the ones that seem to be feasible for the school. Criteria to be considered include: Teaching objectives. The fundamental objective of all academic laboratory experiments is to support the lecture syllabus by demonstrating important chemical principles. In addition, the experiments should teach proper and safe laboratory technique. Therefore, any modifications to experiments must consider how those modifications might impact the experiments teaching objectives. Raw material needs. This criterion addresses the characteristic properties (toxicity, flammability, etc.), quantity,
and cost of raw materials used in an experiment. Resources needed. This criterion addresses the various resources needed for each experiment. Resources include, but are not limited to: laboratory equipment (glassware, mixers, instruments, etc.); facility equipment (fume hoods, laboratory sinks, natural gas, or other specialty gases, etc.); safety equipment (instrumentation, fire suppression, personal protective equipment such as respirators, etc.); and personnel (special skills and training requirements). Waste materials generated. This criterion addresses the type (solid, liquid, or gas), quantity, and characteristics (highly toxic, corrosive, etc.) of the wastes generated by the experiment. Cost. This criterion addresses the capital and unit costs associated with an experiment. Capital costs include, but are not limited to: equipment purchases, instrumentation purchases, modifications to laboratories to accommodate an experiment, and textbook or other purchases to support an experiment. Unit costs include, but are not limited to: chemicals and other consumables, staff resources (including teaching assistants, stockroom attendants, etc.), and waste disposal (solid, hazardous, etc.). Implementation. This criterion addresses how easily an experiment can be implemented. It addresses intangibles such as department and administrative acceptance of change, how easily funding can be obtained to implement changes, ability to properly and efficiently implement changes, and regulations, laws and policies.
Figure 3 shows a sample evaluation matrix. This matrix can be used for both the screening and detailed evaluation of alternatives. For the screening evaluation pluses and minuses can be entered into the appropriate cells. The importance of each parameter (i.e., weight factor for each parameter) may also be used if the team decides it will help in selection of the most feasible alternative. The methodology focuses on teaching laboratories, but is also suitable for research and development laboratory settings.
Ease of Implementation
Cost
Waste Generated
Develop List of Alternatives
ALTERNATIVES
Raw Materials Needed
Develop Evaluation Criteria
Teaching Objectives
Planning and Organization
Screen Alternatives
Detailed Evaluation of Alternatives
Implementation Figure 2. Laboratory pollution prevention methodology.
Figure 3. Evaluation matrix to screen alternatives.
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Develop List of Alternatives The project team will next need to develop a list of potential alternatives for evaluation. The initial list should include all possible alternatives and the project team should not evaluate the merits of any alternative during the identification of potential alternatives. Alternatives may also consist of combinations of viable pollution prevention techniques. The flow diagram shown in Figure 4 presents a methodology for development of alternatives. The methodology includes an evaluation of each potentially applicable pollution prevention technique. As indicated, the project team should first focus on source elimination or reduction techniques. After source elimination or reduction, recycling, treatment, and proper disposal should be considered. In effect, the chart is helping the project team consider each alternative following the EPA hierarchy of preferred options. The alternatives should include the current experiment. The current experimental procedure should also be completely evaluated (using the criteria selected in the develop evaluation section) to determine how chemicals are used, what wastes are generated, and the advantages and disadvantages of the current procedure. This information will provide a benchmark for comparison to the other alternatives. (Note: alternatives may include variations or modifications of the current experiment procedure.) Screen Alternatives In order to effectively screen the alternatives some preliminary information on each one will need to be obtained. This information could include, but is not limited to, the chemical and laboratory equipment needs and the quantity and types of wastes generated. The first step in this evaluation is to eliminate the alternatives that are infeasible for a given school, course, or laboratory. A qualitative screening of the remaining alternatives can be performed using the pre-
liminary information and the evaluation criteria matrix presented in Figure 3. The purpose of the preliminary screening is to eliminate those alternatives that cannot be implemented. At the completion of the preliminary screening only realistic alternatives should be available for further consideration. An efficient way to screen the alternatives is to compare the alternative to the current procedure. If the project team believes that the alternative is more favorable than the current procedure, then the alternative remains for consideration during the detailed screening. If the alternative is deemed to be less favorable than the current procedure, it is eliminated from further consideration.
Detailed Evaluation of Alternatives In this stage of the methodology, a detailed evaluation of the alternatives remaining from the previous step is conducted. The detailed evaluation can be used as fine tuning to determine which possible alternatives might be the most favorable for pollution prevention. If, from the initial screening, only one alternative stands out as the most favorable, then this step may be skipped and the team may proceed to the implementation step. Possible actions to be considered in this step include: Quantitative evaluation of alternatives. To properly perform the detailed evaluation of the remaining alternatives the project team will need to develop detailed information on the various alternatives. The project team should perform this evaluation based on the criteria developed previously and used to preliminarily screen the alternatives. Using the detailed information, comparisons can be made using quantitative data or by weighting qualitative data (i.e., ranking from 1–5). It is important that the criteria evaluation is performed in a systematic manner in order that each alternative be considered properly, and that the recommendations of the project team can be supported and documented.
Source Elimination or Reduction
Recycling and Reuse
Treatment of By-Products
Substitution?
Unused material? Redistribution
Neutralization?
Microscale Scale Down?
Chemical Recovery?
Other Methods?
Waste Disposal
Hazardous Waste?
Hazardous Waste Disposal
Alternative Methods?
Non-Hazardous Waste Disposal
Figure 4. Alternative methods for pollution prevention in laboratories.
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In the Classroom Pilot test recommended alternative. Pilot testing prior to full-scale implementation of an alternative may be appropriate. Pilot testing will allow the project team to develop real-world data and also can assist in making modifications to improve the alternative prior to full-scale introduction. Pilot testing can also identify fatal flaws in the alternatives. This way the alternative can be removed from full-scale introduction with minimal disruption to operations. Final screening. If an alternative is pilot tested the project team will want to review the pilot-test results. If the pilot test is consistent with the expected results, the recommended alternative can be implemented in a broader fashion. If pilot-test results are significantly different from expected results, the project team may wish to re-evaluate the alternatives incorporating the additional information. Implementation. This represents full-scale implementation of the recommended alternative. Monitor and evaluate alternative. The project team will want to monitor the implemented alternative to ensure everything is implemented as intended. Optimize and refine alternative. As necessary, the project team may wish to optimize the implemented alternative based on review of the results of the implementation.
and Risk Management’s Web site, http://www.uri.edu/safety/ data/LSDocs.html (accessed Sept 2002). Conclusions The pollution prevention guideline has been tested and proven to be valuable in assisting academic laboratories to select pollution prevention techniques. Careful examination of existing or future laboratory practices with the aid of this guideline will help eliminate and minimize the amount and toxicity of waste generated. To achieve this goal and avoid conflicts between teaching objectives and EPA regulations, implementation of the guideline requires the essential cooperation of instructors, safety committee, and other university officials. Acknowledgments The development of this paper was made possible through a joint effort of the Rhode Island Center for Pollution Prevention, the Safety and Risk Management Department of the University of Rhode Island, the University of Rhode Island Chemistry Department, Pfizer Global Research and Development–Groton Laboratories, and Environmental Resources Management Inc. Literature Cited
Results This laboratory pollution prevention guideline is presented to assist academic institutions considering pollution prevention alternatives for new or existing laboratory practices. Prior to considering alternatives, the team in charge needs to be knowledgeable about the different approaches for pollution prevention. The first part of the guideline summarized the different methods and illustrated how they can be applied in instructional laboratories. The methodology presented in the next section described the steps used to consider possible alternatives and to select the most suitable one according to the needs and resources of the institution. The methodology was tested in a general chemistry laboratory course at the University of Rhode Island. The outcome was positive, and based on the results, new alternatives are being considered for its full implementation. Further information regarding the implementation of the methodology can be found at University of Rhode Island’s Department of Safety
1. EPA—Pollution Protection Act of 1990. http://www.epa.gov/ opptintr/p2home/p2policy/act1990.htm (accessed Oct 2002). 2. Arnáiz, J. F.; Pedrosa, M. R. J. Chem. Educ. 1999, 76, 1687– 1688. 3. Mahamulkar, B. G.; Dhavale, D. D.; Kelkar, S. L. J. Chem. Educ. 2000, 77, 387–388. 4. Montaña, A. M.; Grima, P. M. J. Chem. Educ. 2000, 77, 754– 757. 5. Ahmad, J. J. Chem. Educ. 2000, 77, 1182–1183. 6. Creary, X.; Morris, M. K. J. Chem. Educ. 1999, 76, 530–535. 7. Johnson, K. A.; Deese, W. C. J. Chem. Educ. 2000, 77, 1451– 1452. 8. Nash, J. J.; Meyer, J. A. R.; Nurrenbern, S. C. J. Chem. Educ. 1996, 73, 1183–1185. 9. Office of the Federal Register, National Archives and Records Administration. Code of Federal Regulations: Protection of Environment, 1992, Vol. 40; U.S. Government Printing Office: Washington, DC.
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