POLLUTION PREVENTION IDENTIFYING, SELECTING AND PRIORITIZING OPTIONS

Transcription

1 Presented at the: American Institute of Plant Engineers Conference Minneapolis, Minnesota September 30 - October 1, 1991 &@+ef POLLUTION PREVENTION IDENTIFYING, SELECTING AND PRIORITIZING OPTIONS Daniel P. Reinke, P.E. Capsule Environmental Engineering, Inc. St. Paul, Minnesota Introduction Environmental regulations have traditionally been viewed by manufacturers as an undesired but necessary evil that adversely impacts the company's financial bottom line. Many companies are beginning to find, however, that avoiding environmental management issues can cost much more than properly addressing them in the first place. This is painfully obvious for companies involved with expensive soil or groundwater remediation projects. One of the latest environmental regulations includes additional requirements that certain facilities prepare formal plans which evaluate the manufacturing processes that generate wastes and emissions. These plans must address how the company will work towards reducing the pollution from the plant by modifying the manufacturing processes rather than through more traditional end-of-pipe treatment methods. Unlike many other regulations, these laws require companies to do what they should be doing in the first place -- to evaluate their processes and find ways to operate more efficiently, Many large firms have already found that this evaluation process makes good business sense. Other firms take a less organized approach by encouraging pollution prevention without having an overall plan. The vast majority of firms seem to survive on a "business as usual'' course, afraid to change any of the processes that have allowed them to survive in the past. Pollution prevention, when viewed as a typical engineering project, is not magic or especially unique. The techniques and procedures presented in this paper are similar to those used when a firm develops a plan to reduce the manufactured cost of a product or improve product quality. The key pollution prevention issues of establishing goals, obtaining management support, developing a leader, selecting a project team,

2 communicating with personnel and assessing operations are the same issues faced in other projects. The only difference is that in these assessments efforts focus on the pollution generated from the manufacturing processes in addition to product quality and manufactured cost. This paper presents how to identify, select and prioritize pollution prevention options. A generic hypothetical manufacturing facility is used as a case study to help explain the principles presented. This paper is meant to follow a paper which uses the same case study facility to address the process of getting started and conducting a pollution prevention assessment. Camule Equipment Company The hypothetical facility used as a case study for our pollution prevention project is called Capsule Equipment, with headquarters and manufacturing facilities in Bora Bora, Minnesota. 'The facility manufacturers a cabinet which contains various small machined parts. The cabinet is made of sheet metal and is painted for both aesthetics and corrosion protection. The internal parts are carbon steel and are zinc plated with a chromate conversion coating to protect them from corrosion. The Capsule plant is a simple operation. Parts are machined and cabinets formed off site and shipped to Capsule weekly. When received, parts are stored until they are needed. Parts are covered with a rust-preventative oil coating at Capsule's supplier to prevent corrosion during storage. As needed, parts are removed from storage and taken to the plant's vapor degreasing cleaning system to remove oil and shop dust. The vapor degreaser is an old model which uses trichloroethylene (TCE). The TCE boils in a sump in the bottom of the degreaser and the fumes rise to a vapor zone. When a cold part is placed in the hot vapor zone, the TCE condenses on the part, removing the "soils." The TCE then drips back into the sump. Cooling coils filled with flowing water maintain a cold zone above the sump through which the heavier-than-air solvent should not escape. Small parts are placed in a basket and hung in the degreaser using a hoist. Panels for cabinets are also supported using the hoist. To reduce employee exposure to the chlorinated solvent a lip vent was installed on the degreaser to remove the fumes. After the parts are cleaned, cabinets are assembled and painted and internal parts are zinc plated. Painting is done using a conventional manual high-pressure spray system which is used to apply the one color of solvent-based paint used on the cabinets. The one painting booth has dry filters to catch paint overspray. -2-

3 Internal parts are zinc plated in a zinc-cyanide plating bath. Parts are placed into barrels and manually carried through the baths on the line. Baths include an electrocleaning tank which is followed by two rinses, an acid activation tank followed by two rinses, the zinc bath followed by two rinses, a chromate tank, a hot rinse and a drying stage. Rinsewater and bath dumps are piped to a wastewater treatment area. Separate lines are used for cyanide-containing, chrome-containing and general wastewaters. Wastewaters containing cyanides are treated with sodium hypochlorite to oxidize the cyanides. Hexavalent chrome is reduced to the less toxic trivalent form using sodium bisulfite. All wastewaters are then combined and the ph of the solution increased to precipitate out the metals. The clean water passes through a clarifier before being neutralized and discharged. The sludge is sent to a filter press, dewatered, collected and shipped off-site as a hazardous waste. Identifying Options The assessment already conducted by the pollution prevention project team has identified a number of processes which contribute to the overall plant wastes and emissions. The mass balances indicate the relative significance of each process as a source of these wastes and emissions. The next step is to walk through each process and identify all options that could reduce or eliminate the wastes and emissions at their source. While this evaluation is typically conducted on a process-by-process basis, a broader view should be considered when identifjmg options. For example, if cleaning is required because parts are supplied containing oils which must be removed, then eliminating the use of the oil in the previous process should be a option for eliminating the cleaning process. Likewise, if the oils are applied to the parts to prevent them from rusting while they sit in storage, then implementing just-in-time manufacturing is a pollution prevention method to eliminate the use of oils and subsequent cleaning. The key to identifymg pollution prevention options is to repeatedly ask one question -- why. Why do we clean?, Why do we paint?, Why do we plate? While this seems overly simple, it does in fact work as long as you keep on asking why, until you get to the source of the problem. There are different levels of issues to address when asking why. The first level is the basic questions noted above which challenge the product design. After these are. addressed, a second level of questions can be asked which cover the processes, procedures and equipment used to make a product. Examples of these questions are Why do we use solvent in the paint?, Why do we store a six-month supply of parts?, Why do we remove the oil with TCE? and so forth. -3-

4 This practice of asking why is one method of identifylng pollution prevention options. A second method is to explain the overall pollution prevention goals to the operators, product designers, process engineers and maintenance personnel most involved with the processes and to solicit their input on how things could be changed to reduce wastes and emissions. These internal resources are extremely valuable and well worth the additional coaxing that may be required to assure people that their ideas will be taken seriously. At this point you should be identifying all possible options. You should not be eliminating or discounting any serious proposals no matter how far-fetched they initially seem. Having a list of ten outrageous ideas may help someone come up with the eleventh wild idea that actually turns out to be worthwhile. Outside resources should also be tapped to assist in identifylng options. Examples of external resources include: Corporate or sister plant personnel Equipment vendors Chemical and material suppliers Trade associations Consultants State Technical Assistance Programs (TAPS) State reports/grants Universities/trade schools EPA - Pollution Prevention Database For companies with multiple facilities, representatives from other plants or from corporate offices can provide a new source of ideas for pollution prevention options. These personnel may have experience in testing a specific option with the product being manufactured. Equipment vendors and chemical suppliers are often an excellent source of information on alternatives. They should not be used as a single source of information, however, since many vendors have a short-term motivation to sell a particular product. A rare few vendors work with a long-term goal of obtaining your business by helping you make a better product more efficiently. Trade associations are another valuable source of information and should be used whenever possible. Examples include the Chemical Coaters Association, the Metal Finishers Association, and the Association of Electroplaters and Metal Finishers. The American Institute of Plant Engineers can also be a valuable source of ideas. Consultants can be an excellent source of information, especially if they specialize in the area you are investigating. Consultants may be able to do certain activities in -4-

5 substantially less time than can your own untrained staff. Hiring a consultant is a new task for many facilities, but there are several suggestions to keep in mind. * Have a clear scope of work * Obtain competitive proposals Investigate the consultant s qualifications * Make the consultant do what they said they would do These concepts are no different from the procedures used to purchase any major piece of equipment, except you are essentially purchasing expertise. It is helpful to select a consultant that understands your operations and can work with the people in your facility. It is especially important that the consultant provide an educated outside view of your operations in order to come up with new ideas. State and federal agencies and universities can also be tapped as a source of information on alternatives for common operations. EPA and some states have on-line computer systems which contain summaries of pollution prevention case studies and projects. In summary, the process of developing options requires brainstorming, asking why and tapping all available resources. All serious options should be written down for later review. This process make take weeks to contact all sources. Every person involved in the manufacturing process may have a good idea which could improve your operations. EvaluatinP Options Once a list of options has been developed, the team must evaluate those options which can address each waste or release and select options for implementation. The goal at this stage is to identify the product, procedure or equipment modifications that will best reduce or eliminate the waste or emission at the company. Obviously, the elimination of waste is not the only factor to be reviewed in this process. There are a great variety of factors that need to be considered when evaluating options. Each facility will have different considerations as to which factors are most important, and these need to be established in order to determine which option is best for the plant. Examples of evaluation factors include: * Capital cost and availability * Operating cost Savings * Environmental impact, both short- and long-term * Occupational hazards impact * Labor requirements or savings * Maintenance requirements or savings -5-

6 Energy requirements or savings Technical risk Product changes required and customer approvals Process changes required Additional facility changes required Production shutdown requirements Technical support required and available Implementation schedule These factors can be combined into two general categories, technical issues and economic issues. Obviously, both are important to assure a successful implementation of the selected options. Typically the technical evaluations are conducted before considering economic issues. Technical Evaluation The technical review of the option includes asking the following types of questions for each option: * * * * * Will it work in this application? Has it worked elsewhere in similar conditions? What are the potential problems? What are the labor and maintenance requirements? What results have others obtained? The internal and external resources listed earlier in this paper can be used to obtain information for the review of options. Before recommending the purchase of equipment, you should view installations or talk with existing users of the equipment. This technical review of each option will identify many options that have a high likelihood of failure. Others will appear to have a high likelihood of success. Generally one's "gut feeling" is a good indicator of whether a particular option has been well researched. If you don't feel comfortable with a particular option, you need to evaluate it further. Typically this technical evaluation can lead to one or two options which hold the most promise for accomplishing the facility's pollution prevention goals. While the identification of these options is typically obvious, in certain instances it may be useful to use a rating system to compare various options. A good example of a weighted average rating system for pollution prevention projects is presented in the EPA publication, '"Waste Minimization Opportunity Assessment Manual." ' US. Environmental Protection Agency. Hazardous Waste Engineering Research Laboratory "Waste Minimization Opportunity Assessment Manual." EPA/625/7-88/

7 For our case study with the cleaning, painting and plating operations, an initial technical review of the ideas generated left these for further review: Product Use plastic or composite housing - eliminate painting Use alternative metals - eliminate plating Cleaning Purchase clean parts - alternative rust protection, minimize storage time Modify soils Use alternative solvents Use aqueous cleaning Use mechanical cleaning Painting Purchase prepainted parts Improve transfer efficiency - process modifications Minimize number of cleanups required Use high solids solvent coatings Use water-based coatings Use powder coatings Plating Use alternative processes - vapor deposition Use noncyanide plating Use alternative coatings Use bath dragout reduction Use bath dragout recovery Use water conservation Use metal recovery The technical review identified several advantages and disadvantages of each option. For example, changing the product to use plastic housings was discarded based on the amount of time and effort that would be required to make and approve the modifications. Switching from the vapor degreasing system to another type of solvent was seen as not having adequate environmental benefits. As a result of this review and evaluation, the following options were identified as those most technically feasible for the facility: Cleaning - Aqueous cleaning system Painting - Powder coating system -7-

8 Plating - Use of noncyanide alkaline zinc process with bath dragout reduction These options were then reviewed for economic impact. Economic Evaluation The economic review of pollution prevention options is generally no different than the typical economic reviews conducted for any capital expansion at a facility. In the review of capital funding for a pollution prevention project, some facilities apply a lower standard for the required payback or return on investment. This is done in an attempt to account for the numerous intangible benefits of pollution prevention. Different sizes of projects typically undergo different levels of scrutiny in a facility. For a project requiring $20,000 in capital funding, a simple letter format explaining the project costs and benefits may be acceptable. For medium-sized projects this review will contain estimated operating costs and savings and will calculate a simple return on investment. For large projects the economic review incorporates equipment depreciations and expected equipment usages and may calculate an internal rate of return on the investment. What level of economic review is required for a particular facility project is usually well defined. The reviewer needs only to obtain the proper information and complete the proper forms. Obtaining the information necessary to conduct the economic review is not always an easy task. Both the capital and operating costs must be developed as well as the expected savings. While vendors can supply much of this information, the numbers must be reviewed by the facility to ensure that it accurately represents the expected costs and benefits for the plant. This review should again utilize the internal and external resources identified earlier in this paper. Prioritizinp Options At this point all of the pollution prevention options have been identified, evaluated and selected for all of the processes, wastes and emissions. In any real facility there are limited personnel and financial resources which prevent all options from being implemented at the same time. The last part of the review, therefore, involves prioritizing the various selected modifications. Several factors are used to prioritize the projects available for a facility. Each factor presented below will have a different importance for different facilities. If capital is not readily available for a plant, then low-cost items will be done before capital-intensive projects, regardless of the environmental impact. If obtaining immediate results is important, then a project which may require an extensive permitting process will not be favored. -8-

9 Significance One of the key factors is the environmental and economic significance of the option. An option that has a high environmental impact, such as eliminating the use of chlorinated solvents, will be preferred over one that would reduce wastewater sludge volume by 10 percent even though the wastewater project may have a higher return on investment. Technical Requirements/Feasibility Projects that have a higher technical risk or require significant technical support may not be appropriate for a facility with limited technical staff. This issue is often a concern at smaller facilities and can make a economically sound option unfeasible until adequate technical support is available. Staffing Abilities Some projects require additional attention from manufacturing or maintenance staff for startup and initial operation. This factor can be a concern and may require initial implementation of pollution prevention projects which do not need staff support. Anticipated Product Changes If major product or process changes are planned for a facility, it may make sense to delay implementation of certain projects and incorporate them into the planned changes. For example, it would not be wise to invest in a dry powder coating system as a solvent paint replacement if the facility planned to change to plastic parts. Ease of Modifications - Customer Role Some customers, such as the military and automotive manufacturers, require that any major product revisions be approved prior to being installed. This review process can take many months and lots of labor. A company may select to wait on proposing certain modifications until other modifications are also desired to minimize the number of customer approval projects. Availability of Capital For plants with lean capital budgets, this factor is extremely important. Often facilities operate with minimal capital expenditures for a limited amount of time. During this time efforts can focus on low-cost projects, with larger projects delayed until better economic times. -9-

10 ... ' L Summary Identification of pollution prevention options is best accomplished using the "controlled brainstorming" technique presented in this paper. Both internal and external resources need to be tapped to develop a comprehensive list of options which can then be evaluated. Soliciting ideas from all personnel who will later be involved in the project implementation also helps them to feel a part of the overall project and contributes to later success. Selecting options for implementation is done by evaluating the technical and economic merits of each reasonable option. Plant-specific concerns are used to evaluate and select options. Technical and economic evaluations are completed using the same list of resources used to generate pollution prevention options. Prioritizing options is done to determine which of the selected options should be addressed first. Prioritization considers a variety of factors including the project significance, the technical feasibility, staffing requirements, anticipated product changes, customer requirements and availability of capital. Once items are prioritized, an overall facility plan can be developed and projects implemented