Virginia Waste Minimization Program
Vol. 1 Issue 1
A Fact Sheet Overview from the Virginia Waste Minimization Program on waste reduction techniques.
Liquid, solid. and/or gaseous waste materials are always generated during the manufacture of any product. In addition to environmental problems, these wastes represent losses of valuable materials and energy from the production process and a significant investment in pollution control. Traditionally. pollution control focuses on "end-of-pipe" and "out-the-back-door" viewpoints. The control of pollution in this way requires manpower, energy, materials, and capital expenditures. Such an approach removes pollution from one source, such as wastewater treatment or air pollution abatement. but places pollutants somewhere else. such as a landfill.
Added regulations, higher disposal expenses, and increased liability costs have caused industrial and governmental leaders to begin critical examinations of end-of-pipe pollution control measures. The value of waste reduction has become apparent to industries that are taking the opportunity to look at broader environmental management objectives rather than concentrating solely on pollution control. As documented throughout this paper, waste reduction is very often economically beneficial for an industry and also results in improved environmental quality.
Waste reduction techniques may be applied to any manufacturing process for a product as simple as a paper clip to as complex as a space shuttle. Available techniques range from easy operational changes to state-of-the-art recovery equipment. The common factor in these techniques concerns the reduction of bottom line operational costs.
Waste reduction techniques may be broken down into four major categories: inventory management, production process modification, volume reduction. and recovery. Because the classifications are broad. some overlap occurs. In the actual application of these methods, waste reduction techniques generally are used in combination with each other to achieve the maximum effect at the lowest possible cost.
Proper control over raw materials, intermediate products, final products and their associated waste streams, is an important waste reduction technique (1). In many cases, waste is just out-of-date raw materials, is off-specification from what is required. or consists of contaminated or unnecessary raw materials. spill residues. or damaged final products. The cost of disposing of these materials not only includes actual disposal costs but also the cost of lost raw materials or product. Methods for controlling inventory range from simple changes in ordering procedures to implementation of just-in-time manufacturing techniques. Many companies may help reduce their waste generation by tightening up and expanding their current inventory control programs. This action will significantly impact the three major sources of waste that result from improper inventory control: excess, out-of-date. and no-longer-used raw materials.
Purchasing only the amount of raw materials needed for a production run or a set period of time is a key to proper inventory control. Excess inventory often must be disposed of because it becomes out- of-date. Companies may eliminate this problem by more effective application of existing inventory management procedures. This method should be coupled with the implementation of educational programs for purchasing personnel on the difficulties and costs associated with disposal of excess materials. Additionally, set expiration dates should be evaluated. especially for stable compounds, to see if they are too short. For example, if inventories are not available for production because the raw materials have passed an expiration date, the supplier/manufacturer should be contacted in order to improve the situation by getting materials that will last longer. Or, production methods may be varied to use soon-to-expire materials faster.
Developing review procedures for all materials purchased is another step in establishing an inventory control program. Standard procedure should require that all materials be approved prior to purchase. In the approval process, all production materials are evaluated to determine if they contain hazardous constituents, and if so, what alternative non-hazardous substitute materials are available. The development of review procedures may be made either by one person having the necessary chemistry background or by a committee consisting of people that have a variety of backgrounds. Needed information may possibly be obtained from the Material Safety Data Sheets (MSDS) provided by the chemical supplier. Many companies from electronics to textile firms have established successful materials review programs (2,3).
The ultimate in inventory control procedures is just-in-time (Jrll manufacturing, since this method estimates the need for inventory. This process is done by moving raw materials directly from the receiving dock to the manufacturing area for immediate use. The final product is then shipped out without any intermediate storage. Just-in-time manufacturing is a complex program to implement and cannot be used by all facilities; however, this technique may reduce waste significantly. For example, the 3M Company reduced waste generation by 25 to 65% in their individual plants by using Jrll techniques (1).
Improving the efficiency of a production process can significantly reduce waste generation at the source of generation. Some of the most cost-effective reduction techniques are included in this category; many methods are simple and consist of relatively inexpensive changes to production procedures. Available techniques range from the elimination of leaks in process equipment to the installation of state-of-the-art production equipment. Waste reduction techniques in this category may be divided into the categories of improved operation and maintenance. materials change. and equipment modification.
A wide range of methods are available to operate a production process at peak efficiency. These methods are neither new nor unknown and are usually inexpensive to institute. as little or not capital cost is necessary. For example, a producer of breaded foods instituted a number of operational changes such as dry cleanup, installation or modification of drip trays under process equipment, and development of better systems for the collection and handling of waste materials. These methods decreased water usage by about 30%. eliminated the landfilling of waste solids. reduced the organic load of the wastewater by almost 80%, and allowed the company to sell 2.359,000 kg (5,200,000 pounds) per year of solids to recovery firms (4).
Improved operation procedures are quite simply methods that make optimum use of the raw materials employed in the production process. The first step in Instituting such a program is to review all current operational procedures and to examine the production process for ways to improve Its efficiency. A review would include all segments of the process, from the delivery area through the production process to final product storage.
One important area that is commonly overlooked or is not given proper attention in many manufacturing facilities is material handling procedures. Proper material handling will insure that raw materials will reach the production process without loss of material through spills, leaks or contamination. This method guarantees that the material is efficiently handled in the production process.
Once proper operating procedures are established, they must be fully documented and made part of an employee training program. A comprehensive training program is a key element of any effective waste reduction program. Through training, for example, a dairy plant, a semiconductor manufacturer, and a furniture plant reduced waste by 14%, 40%, and 10% respectively (5,6,7). For a program to be effective, all levels of personnel should be included, from the line operator to the corporate executive officer. The goal of any program is to make the employee aware of waste generation, its impact on the company and the environment, and ways that waste may be reduced. Written materials should be prepared and used in conjunction with hands-on training. This process should be employed constantly, and review updates and interaction between employees and supervisors should be carried out on a regular basis.
One company found that one-fourth to one half of its excess waste load was due to poor maintenance (8). A strict maintenance program that stresses corrective and preventive maintenance can thus reduce waste generation caused by equipment failure. Such a program will help to spot potential sources of release and to correct the problem before any materials are lost. A good maintenance program is important because the benefits of the best waste reduction program may be wiped out by just one process leak or equipment malfunction. A maintenance program may include maintenance cost tracking and preventive maintenance scheduling and monitoring. To be effective, a maintenance program should be developed and followed for each operational step in the production process, with special attention given to potential problem points. Strict schedules and accurate records of all maintenance activities should be maintained. Computer-based maintenance scheduling and tracking programs are also available from a variety of vendors. A comprehensive program should also include predictive maintenance: this approach provides a means to schedule repairs or replacement of equipment based on the actual condition of the machinery. A number of non-destructive testing technologies are available for making the needed evaluations in this approach.
Hazardous materials used either in the fonnation of a product or in a production process may be replaced with less hazardous or non- hazardous materials. Reformulating a product to contain less hazardous material will reduce the amount of hazardous waste generated during both the product's formulation and end use. Using a less hazardous material in a production process will generally reduce the amount of hazardous waste produced. This action in turn could reduce the cost of capital equipment needed to meet environmental regulatory limits.
Product reformulation is a more difficult waste reduction technique. yet reformulation can be very effective. Examples of product reformulation include the elimination of pigments that contain heavy metals from ink, dyes and paint formulations; the replacement of phenolic biocides with less toxic compounds in metal-working fluids; and the development of new paint, ink and adhesive formulations based on water rather than organic solvents.
Hazardous chemicals used in the production process may also be replaced with less hazardous or non-hazardous materials. Changes may range from the use of purer raw materials to the replacement of solvents with water-based products. This method is a very widely- used waste reduction technique and is applicable to many industries. Many of these changes involve switching from a solvent to a water-based process solution. For example, a diesel engine remanufacturing facility switched from cleaning solvents and oil- based metal-working fluids to water-based products. This change reduced its coolant and cleaning costs by about 40%. Additionally, the company was able to eliminate one cleaning step and machine filters lasted twice as long. thus reducing material and labor costs (14).
One important area that is sometimes overlooked in making a material change is the modification's impact on the total waste stream. By switching from a solvent-based to a water-based product. a firm may increase wastewater volumes and concentration. This action could adversely affect the current wastewater treatment system, cause effluent limits to be exceeded, and possibly increase wastewater treatment sludge production. Thus. before any change is made, its impact on all discharges must be evaluated.
Waste generation may be reduced by installing more efficient process equipment or by modifying existing equipment to take advantage of better production techniques. New or updated equipment can use process materials more efficiently and thereby produce less waste. In addition. higher efficiency systems may reduce the number of rejected or off-specification products, thereby reducing the amount of material that must be reworked or disposed.
Modifying existing process equipment can be a very cost-effective method to reduce waste generation. In many cases this technique may consist of relatively simple and inexpensive changes in the way the materials are handled within the process to insure that they are not wasted or lost. This method can be as easy as redesigning parts racks to reduce drag-out in electroplating operations, installing better seals on process equipment to eliminate leakage, or installing drip pans under equipment to collect leaking process material for reuse. One chemical company reduced its waste from a sump in a production area from 31,750 kg/year to 1,360 kg/ year by installing a sight glass, using better pump seals and purchasing a broom (16). Installing new and more efficient equipment and. in some cases. modifying current equipment, will require capital investment in equipment. facility modifications and employee training. The extent of this investment will vary greatly depending on the type of equipment employed. These investments, however, can have a rapid payback. For example, a power tool manufacturer replaced a spray solvent paint system with a water-based electrostatic immersion painting unit. This modification decreased material costs by $600,000/yr, reduced waste disposal costs by 97%. and greatly increased productivity (17).
Volume reduction includes techniques that separate toxic, hazardous and/or recoverable wastes from the total waste stream. These methods are usually used to increase recoverability; to reduce the volume of wastes, and thus disposal costs: or to increase management options. Available techniques range from simple segregation of wastes at the source to complex concentration technology. These techniques may be divided into two general areas; source segregation and waste concentration. Only those methods that are actual waste reduction techniques will be discussed in this section.
Segregation of wastes is, in many cases, a simple and economical technique for waste reduction. For example, by segregating wastes at the source of generation and by handling hazardous and non- hazardous waste separately, waste volume and thus management costs may be reduced. Additionally, uncontaminated or undiluted wastes may be reusable in the production process or may be sent off-site for recovery.
This technique applies to a wide variety of waste streams and industries and usually involves simple changes in operational procedures. For example, in metal finishing facilities, wastes that contain different types of metals can be treated separately so that the metal values in the sludge may be recovered. Keeping spent solvents or waste oils segregated from other solid or liquid waste may allow them to be recycled. Wastewater that contains toxic material should be kept separate from uncontaminated process waste, reducing the volume of water that must be treated.
A commonly used waste segregation technique is to collect and store for reuse in the production process washwater or solvents that are used to clean process equipment (such as tanks, pipes. pumps, or printing presses). This technique is used by paint, ink, and chemical formulators as well as by printers and metal fabricators. For example, a printing firm segregates and collects toluene used for press and roller cleanup operations. By segregating the used toluene by color and type of ink contaminant. the solvent may be reused later for thinning inks of the same type and color. The firm now recovers 100% of its waste toluene, thereby totally eliminating a hazardous wastestream (17).
Various techniques are available to reduce the volume of a waste through physical treatment. Such techniques usually remove a portion of a waste, such as water. Available concentration methods include gravity and vacuum filtration. evaporation, ultrafiltration, reverse osmosis, freeze vaporization. filter press, heat drying, and compaction. Many of these processes actually are recovery techniques and will be discussed further in the next section.
Unless the material can be recycled. simply concentrating a waste so that more can be "fit into a drum" is not waste reduction. In some cases, the concentration of a waste stream may also increase the likelihood that the material can be reused or recycled. For example. filter presses or sludge driers can increase the concentration of metals in electroplating wastewater treatment sludge to such a level that the metals become valuable raw material for metal smelters. A printed circuit board manufacturer dewaters its sludge to 60% sludges by using a filter press. The company receives $7.200/year in the sale of the dewatered sludge to copper reclaimers (17).
Recovered wastes can provide a very cost-effective waste management alternative. This technique can help eliminate waste disposal costs, reduce raw materials costs, and possibly provide income from a saleable waste. Recovery of wastes is a widely used practice in many manufacturing processes and may be done on-site or at an off- site facility.
The effective use of recovery techniques will depend on the segregation of recoverable waste from other process wastes or extraneous materials. This action ensures that the waste is uncontaminated and the concentration of recoverable material is maximized. Some companies have assigned the responsibility of all handling, collection, and scheduling for recovery of waste material to one individual (4,23). This modification helps to insure that the maximum value of the waste will be recovered.
In most cases, the best place to recover process wastes is within the production facility. Wastes that are simply contaminated versions of process raw materials are good candidates for in-plant recycling. Waste may be most efficiently recovered at its point of generation. The possibility of contamination by other waste materials is reduced, as is the risk involved with the handling and transporting of waste materials. if each waste is segregated. and properly handled, on-site.
Some waste streams can be reused directly in the original production process as raw material. This action is usually accomplished when waste material is lightly contaminated or is excess raw material. Examples include: cleaning wastes from printers, coaters, and chemical or product formulators. Lightly contaminated waste may sometimes be reused in operations that do not require high-purity materials. For example. spent high-purity solvents generated during the production of microelectronics can be reused in less critical metal degreasing operations. A caustic waste material can be reused in less critical metal degreasing operations or in treating an acid waste stream.
Wastes may have to undergo some type of purification before they can be reused. A number of physical and chemical techniques available on the market may be used to reclaim a waste material. These methods range from simple filtration to state-of-the-art freeze crystallization. The technique of choice will depend on physical and chemical characteristics of the waste stream, recovery economics. and operational requirements. Most on-site recovery systems win generate some type of residue (i.e., the contaminants removed from the recovered material). This residue may either be processed for further recovery or properly disposed. The economic evaluations of any recovery technique must include the management of these residues.
Wastes may be recovered at an off-site facility when the equipment is not available to recover them on-site, when not enough waste is generated to make an in-plant system cost-effective. or when the recovered material cannot be reused in the production process. Off-site recovery usually entails the recovery of a valuable portion of the waste through chemical or physical processes. Some materials that are commonly reprocessed off-site are oils. solvents,electroplating sludges and process baths, lead-acid batteries, scrap metal. food processing waste, plastic scrap, and cardboard. The cost of off-site recycling will depend on the purity of the waste and the market for the waste or recovered material.
In some situations, a waste may be transferred to another company for use as a raw material in its manufacturing process. This exchange can be economically advantageous to both firms as it will reduce the waste disposal costs of the generator as well as reduce the raw material costs of the suer. For example. an x-ray film manufacturer produces a saleable product from waste film stock. The company installed equipment that flakes and bales waste polyester-coated film stock, which is sold as raw material input to another firm. Over 9 million kilograms (20 million pounds) of film stock is exchanged each year, representing a $200.000 annual savings in collection, transport, and processing costs and an annual profit of $150,000 from the sale of the materials (17).
The upgrade of a waste into a product requires a strong commitment from the generator to find markets, both inside and outside the company, for the waste material. In some cases. the production process or the waste may have to undergo some modification in order to make a more saleable product. Regional waste exchanges have been set up by a number of states to help companies find markets by acting as information clearinghouses of wastes available and wanted. The service usually offers a listing of wastes available from generators and wasted by users in a catalog or computer database form. The Southeast Waste Exchange in Charlotte, NC covers Virginia and may be reached at 704-547-2307.
As has been shown, a wide range of waste reduction techniques currently exist and are available for most manufacturing steps. However, technology alone will not reduce waste generation--only a comprehensive waste reduction program will be successful. Such a program should include management commitment, data collection. cost-effective technology selection and implementation, employee training and involvement, and program monitoring. The foundation of any successful program is the evaluation of the wastes that are generated and the reasons they are produced. Using this information. a range of reduction techniques can be identified and evaluated, and cost-effective options implemented (Reference 25 presents a detailed overview of how to develop and implement a waste reduction program).
In the final analysis. waste reduction depends on looking at waste in a different way: not as something that inevitably must be treated and disposed. but rather as a loss of valuable process materials, the reduction of which can have significant economic benefits. One corporate executive summarized it all when he stated that waste is a specialty product for which a market has not yet been found.
(This document was reprinted with permission from the North Carolina Pollution Prevention Program. Modifications have been made to tailor this fact sheet for use in Virginia.)
This Waste Reduction Fact Sheet is provided as a service of the Virginia Waste Minimization Program, a technical assistance program of the Virginia Department of Waste Management.
For more information on opportunities to reduce waste contact:
Virginia Waste Minimization Program
11th Floor Monroe Building, 101 North 14th Street
Richmond. Virginia 23219
804-371-8716 or 1-800-552-2075
TDD 804-371-8737