The Six Sigma Approach to Solid Waste Management and Minimization: Moving toward

Abstract: This article provides an overview of an eleven step solid waste analysis and minimization process that is based on the six sigma approach to problem solving that may be applied at a wide variety of organizations. The six sigma approach provides a holistic process that focuses on minimizing defects, in this case, eliminating waste disposed at landfills. As many organizations are moving towards “zero landfill” facilities, such a process is needed to aid in achieving these goals. The eleven step processes provides details on establishing goals, creating process flowcharts, conducting waste sorts, data collection, establishing baseline data, identifying improvement opportunities, cost justification, executing improvement plans and validating results. The article also includes a case study that applies that eleven step process. The goal of the article is to provide the audience with a structured process to evaluate and minimize solid waste generation based on cost justified improvement opportunities.

Key words: Six sigma, solid waste auditing, zero landfill, solid waste minimization.

1. Introduction

1.1 Need for Waste Audits

In 2007, the United States generated 254 million tons of MSW (municipal solid waste), up from 205 million tons in 1996. During this time, recycling levels increased to 63 million tons, from 29 tons in 1996 [1]. Although improvements have been made, efforts are still needed to control and minimization solid waste generation. Such studies are relevant from an international perspective as well. In 2002, China generated 136.5 million tons of municipal solid waste and 945 million tons of industrial waste, of which over 89% were disposed at landfills [2]. These numbers demonstrate the need for this type of research internationally.

Industrial solid waste management and minimization is an effective tool that is a necessary aspect in business today. Firms are discovering it to be a profitable approach, while at the same time enhancing their company image as environmentally conscious and responsible. In the extremely competitive world of manufacturing, waste disposal is often overlooked. There are measurable costs associated with excess raw material, scrap parts, insufficient use of resources, and outdated materials. All these factors contribute to a company’s waste stream, and must be included when calculating cost of disposal. However, many companies do not possess the proper resources to effectively and efficiently manage and minimize their solid waste steams. External consultants are often required to enable companies to optimize their solid waste handling and disposal and minimize waste costs. Waste analysis and minimization can be advantageous to companies in improving their financial position and competitiveness.

1.2 Background

The Environmentally Conscious Design and Manufacturing Lab, located at the College of Engineering at The University of Toledo (Ohio) performed no cost solid waste assessments for Lucas County businesses and industries. Funding is provided by a grant from The Lucas County Solid Waste Management District with support from The University of Toledo. University of Toledo students and faculty conduct the waste assessments. The primary focus of the project is to identify cost savings for local manufactures through waste minimization and process efficiency solutions by increasing manufacturing competitiveness through reduced solid waste disposal costs and optimizing the use of raw materials, packing, and floor space. Typically the assessments consist of: (1) an analysis of the company’s process and overall solid waste generation;(2) recommendations designed to help maximize process efficiency and reduce solid waste disposal costs; and (3) submitting a detailed reference list of vendors that complement the recommendations. Details regarding the history and operation of this project were discussed in previous research [3].

1.3 Zero Landfill Facilities

Zero landfill facilities represent a philosophy that encourages the redesign of resource life cycles and processes so that all products are reused and any trash sent to landfills is minimal. In industry this process involves creating commodities out of traditional waste products, essentially making old outputs new inputs for similar or different industrial sectors. Common methods utilized at zero landfill facilities include, material reuse, recycling, composting, and energy conversion from solid waste that would normally be disposed at landfills. Zero landfill sites require a major shift in the culture of an organization and usually impacts all areas of the organization including purchasing, processing, and administrative functions.

Zero waste can represent an economical alternative to waste systems, where new resources are continually required to replenish wasted raw materials. It can also represent an environmental alternative to waste since waste represents a significant amount of pollution in the world.

2. Materials and Methods

After the need has been established to minimize solid waste generation and top management supports and allocates the necessary resources to the effort, a solid waste assessment can be conducted at a facility. The solid waste assessment is one of the most important steps of the solid waste minimization process because the data generated provides the team and management with a much greater understanding of the types and amounts of waste generated by the company. These data can be invaluable in the design and implementation of a waste minimization program. The methodology used in the waste analysis and minimization process was adapted from a nine step process created by the US EPA [4]. Additional, information from a 1996 study was included in the audit process [5]. Both studies were enhanced with six sigma concepts. Before “rushing in” to conduct a solid waste assessment, proper planning should be done to ensure the scope, goal, and timeline of the project fits into the strategic plan of the organization. This section provides the framework to ensure that these goals are met using the five-step six sigma DMAIC process [6]:

Define—establish the project team, determine the goal, and allocate the necessary resources;

Measure—conduct a solid waste assessment and review existing records;

Analyze—statistically analyze the data collected to identify trends;

Improve—modify the process to meet the organizational goals established in Define stage;

Control—ensure that the improvement initiatives stay in place with continuous improvement and feedback.

Six sigma is a comprehensive and flexible system for achieving, sustaining and maximizing business success. It is uniquely driven by a close understanding of customer needs; disciplined use of facts, data, and statistical analysis; and diligent attention to managing, improving, and reinventing business processes [7]. The six sigma approach examines the organization as a whole, or a sum of all business processes to achieve established goals. The concept is to use data to develop comprehensive system wide changes that will drive environmental and economic performance versus routine incremental improvements. Traditional waste management focuses on managing waste streams after the fact at the end of production processes. Six sigma examines the full processes that generate the waste, including raw material selection. Six sigma gained popularity during the 1990s after Motorola and General Electric achieved significant quality improvement [7]. In their cases, these companies applied six sigma to reduce variation and defects in final products. In the case of solid waste minimization, a defect is defined as waste entering the landfill generated from the facility. The hierarchy of solid waste (reduce, reuse, recycle, compost, energy recovery) is applied to evaluate and select alternative to minimize waste. Defining landfill waste as a“defect” helps to shift the mindset from “business as usual” to the zero landfill philosophy. The audit process identifies waste that should be captured in existing waste reduction practices (for example aluminum cans in break areas) and waste streams that have not been considered for minimization (such as plastic banding in a manufacturing operation that is not being recycled).

In addition, several examples will be provided to further explore and explain each step of the framework. The solid waste minimization process consists of eleven steps:

Establish the solid waste minimization team and charter;

Review existing solid waste and recycling records;

Create process flow charts and conduct throughput analyses;

Conduct the solid waste sorts at the facility;

Analyze the data to determine annual generation by work unit or area and establish baseline data;

Identify major waste minimization opportunities;

Determine, evaluate, and select waste minimization process, equipment, and method improvement alternatives;

Develop the waste minimization deployment and execution plan;

Execute and implement the waste minimization plan and timeline;

Validate the program versus goals;

Monitor and continually improve performance.

3. Results and Discussion

3.1 Establish the Team and Define the Project

After identifying the need to minimize solid waste and gaining top management support, the first step in process involves establishing the team and defining goals. The key outcomes and deliverables of this step are:

a letter of support from top management to all employees;

team leader and member identification;

initial training for the team;

project goal identification including metrics;

team charter;

project timeline;

project budget.

The goals of the project should be clearly expressed as soon as possible. This will provide the team with much needed direction and serve as the gauge to evaluate all team activities and accomplishments. The goals should provide a specific direction for the project and not vague generalized improvement slogan such as “to become an environmental leader in the automobile engine manufacturing field” or “to reduce the organization’s carbon footprint”. A more specific, goal, such as:

Reduce the amount of solid waste generated per year by 5% from the baseline year of 2010;

Increase the recycling rate for metals and paper products by 10% from the baseline year of 2010;

Utilize environmental improvements as a strategic weapon to provide a cost benefit of 10% versus the baseline year of 2010 for expenditures and revenues solid waste removal and recycling efforts.

The project timeline is one of the key deliverables from the “define” stage. The timeline tracks project performance versus established goals and serves as the strategic implementation plan. The timeline should be viewed as a control document to evaluate the progress of the team versus pre-established milestones. Proper planning is needed to ensure the timeline is achievable and will meet the goals of the project. Table 1 displays general guidelines for the time required for each step solid waste minimization process.

3.2 Review Existing Records

Reviewing the existing organizational records for solid waste and recycling usually provides significant insight into the amounts, types, and patterns of waste generation. Very useful data and information can be gained to help focus the efforts of the team and eliminate the need for the collection of existing raw data. Collecting high quality records will save a great deal of time, money and effort versus raw data collection via a trash sort or facility walk-through. The types of records to collect include:

purchasing, inventory, maintenance, and operating logs;

supply, equipment, and raw material invoices;

equipment service contracts;

repair invoices;

waste hauling and disposal records and contracts(including one year of amounts and fees collected);

contracts with recycling facilities and records of earned revenues from recycling;

major equipment list;

production schedule (representative of a year);

company brochure or product information;

MSDS (material safety data sheets);

facility layout (hard copy plus CAD copy, if available);

process flow diagrams.

The purpose of reviewing these records is to determine total amount of waste generated annually, the total amount of material recycled annually, and the total waste removal and recycling cost structure. A review of purchasing records can also be beneficial to “backtrack” into an estimate of waste components generated. For example, shipments often arrive in cardboard containers. By researching the number of containers received per year and estimating the weight per carton, the team could estimate the total weight of cardboard boxes disposed each year. Often times, the janitorial staff, maintenance, purchasing, and accounting staff will be most useful when gathering these records. In addition, customer service at the waste hauling and recycling companies may record more detailed records than the information that appears on monthly invoices.

3.3 Process Mapping and Production Analysis

The goal of this step is to aid the team in fully understanding the business processes and capabilities of the facility. An understanding of these processes is crucial in developing alternatives to reduce solid waste. A process flow chart is a hierarchical method for displaying processes that illustrates how a product or transaction is processed. It is a visual representation of the work-flow either within a process or an image of the entire operation. Process mapping comprises a stream of activities that transforms a well defined input or set of inputs into a pre-defined set of outputs.

A well developed process flow chart or map should allow people unfamiliar with the process to understand the interaction of causes during the work-flow and contain additional information relating to the solid waste minimization project (such as tons of waste generated per year and annual cost of disposal).

3.4 Solid Waste Sorts

Solid waste sorts provide detailed data regarding the composition of an organization’s waste stream. Via the data collected from the solid waste sorts, the organization’s waste stream can be characterized into the various materials that comprise the entire stream, including the annual amounts generated and the percentage that each component contributes to the entire waste stream. This data is invaluable when evaluating cost effective methods or process changes to divert these components from landfills. The waste sort itself is affectionately referred to as “dumpster diving”, since the team will physically collect, sort, and weigh a representative sample of the organization’s waste. This remainder of this section discusses the process to conduct a waste sort, including the required preparation, tools required, a step-by-step guide, and also provides data collection forms.

The team meeting prior the waste sort should be held to get the team on the same page. The primary outcomes from this meeting are training and a waste sort plan. The training should be conducted by the technical expert and focus on the use of tools and data collection form. The waste sort plan should assign team members to the various areas of the facility to conduct data collection effectively and efficiently. The equipment required for the waste sort includes:

gloves;

yard sticks;

plastic bags;

scales;

clipboards (with the data collection from).

Based on the size of the facility, it may be necessary to recruit additional support to collect data during the waste audit. If additional help is used, these individuals should receive the same training as the core team. An approach that seems to work well is to assign one temporary team member from each work unit within the facility. For example, assign a supervisor or shop floor worker from each production work area such as the metal stamping unit, the paint shop, and the accounting offices (work units will differ by business type). The advantages of assigning temporary team members within each work unit include faster and more accurate data collection. As a member of the work unit in which data is being collected, the temporary team member will possess specialized knowledge on the waste generation types and amounts.

The data collection form is the most important document of the waste sort. The data collected with the form will be used to extrapolate the annual generation for the facility so care should be taken when collecting the data to ensure accuracy. At a minimum, the required information on the data collection form is:

the date the data was collected;

the team members collecting the data (this is very useful if follow up or clarification is needed);

work unit and location of the waste receptacle;

source of the waste (previous operation or supplier);

disposal method (baler, compactor, recycler, un-compacted dumpster);

size of the container in cubic feet (can be derived from length, width and height measurements);

the container type (desk side, recycling bin, dumpster);

percent full;

times emptied (per day, week or month);

container contents and percent of each component;

condition of material (loose, compacted, baled);

notes and comments that may be useful when analyzing the data (including names and contact information for work units members with specialized knowledge of the waste or generation levels).

3.5 Data Analysis

The primary outcome of the analysis phase is the annualized waste generation baseline data for the facility. This baseline data should be broken down by the component waste stream (paper, metal, etc.), work unit of generation, and how the component waste stream is currently handled (landfill, recycled, burned, etc.). Each component should be given in terms of weight (tons per year) and volume (cubic yards per year). The key questions that are answered from this analysis are:

What are the waste streams generated from the facility and how much?

Which processes of operations do these waste streams come from?

Which waste streams are classified as hazardous and which are not? What makes them hazardous?

What are the input materials used that generates the waste streams of a particular process or facility area?

How much of a particular input material enters each waste stream?

How much of a raw material can be accounted for through fugitive losses?

How efficient is the process?

Are any unnecessary wastes generated by mixing otherwise recyclable hazardous materials with other process wastes?

What type of housekeeping practices are used to limit the quantity of wastes generated?

What types of process controls are used to improve process efficiency?

How much money is the company paying to dispose of solid waste and how much revenue does it generate from the sale of recyclable materials?

To answer these questions and to generate the baseline data, the existing records collected, the data gathered during the waste audit, and team member knowledge will be used. Additional data collection or verification may be required during the analysis portion.

After all data has been entered into the spreadsheet, annual generation in terms of weight and volume can be tabulated. To estimate the annual waste stream in both terms of weight and volume is very important because, in general, waste haulers charge based on volume (cubic yards that fill a dumpster) and processors pay for recyclable materials based on weight (tons in a bale). Below is an example calculation for cardboard (OCC).

A company reported using a dumpster of 12 cubic yards that was used exclusively for compacted OCC(cardboard) that was emptied two times per month by a recycling vendor. This data was converted into annual tonnage using Eqs. (1) and (2).

Tons per Year = (Dumpster Size in cubic yards)

× (Times Emptied per Month) × (12 Months per Year)

× (EPA Average Material Density - tons/cubic yards) (1)

OCC = (12 cubic yards) × (2/month) × (12 months/year) × (0.45 tons/cubic yard) = 129.6 tons of OCC per year (2) 3.6 Identify Minimization Opportunities

After the baseline data has been calculated, the assessment team can begin to investigate individual components in the waste stream that should be targeted for reduction, reuse, or recycling. A useful method to accomplish this task is to conduct a Pareto analysis. A Pareto analysis is a statistical technique in decision making that is used for the selection of a limited number of tasks that produce the significant overall effect. Pareto analysis is a formal technique useful where many possible courses of action are competing for your attention. In essence, the problem-solver estimates the benefit delivered by each action, then selects a number of the most effective actions that deliver a total benefit reasonably close to the maximal possible one. The analysis uses the Pareto principle, which states that a large majority of effects are produced by a few key causes, in this case waste generation. The Pareto principle is also known as the 80/20 rule that 80% of the effects are caused by 20% of the causes. The idea is to identify the 20% significant wastes components that generate 80% of the total waste and then target that 20% of significant causes for waste minimization.

3.7 Evaluate and Select Minimization Alternatives

Once the major waste streams have been quantified, the team can begin to develop alternatives to minimize the solid waste and move closer to the ultimate goal of the project. In this phase of the project, the team identifies alternatives to minimize the major components of the waste stream and evaluates the economic and operational feasibility while rating each alternative on its ability to achieve the waste minimization goal. This section covers the process to generate, screen, and select waste minimization alternatives. In addition, a comprehensive list of common materials that can be reduced, reused, or recycled and a list of common waste minimization alternatives is also provided.

3.7.1 Generating Alternatives

The alternatives are based on the existing records review, the waste audit results, and the analysis phase. Various methods and tools are available to develop the initial list of alternatives. The environment in which these alternatives are created should be done in one that encourages creativity and free thinking by the team. Following is a suggested list of methods to identify and create these alternatives:

discussions with trade associations;

discussions with plant engineers and operators;

internet and literature reviews;

information available from federal, state or local governments;

discussions with equipment manufacturers or vendors;

discussions with environmental or business consultants;

brainstorming;

benchmarking.

3.7.2 Common Waste Minimization Alternatives(Materials and Methods)

This section provides a brief list of common solid waste minimization alternatives that many companies have successfully implemented. When considering alternatives to minimize waste, the solid waste minimization hierarchy should be considered. Consideration should first be given to reducing the waste (find a process or purchasing change to prevent generating the waste in the first place), next reuse the waste item, and next recycle the waste item, and

finally disposal at the landfill. Source reduction can be accomplished through process modifications, technology changes, input material changes, or product changes. The following list provides commonly applied waste reduction and reuse opportunities that many companies have successfully implemented. Most of these are relatively low cost and are considered the “low hanging fruit”, or simple to launch.

? Office paper—many easy options exist to reduce office paper usage including implementing an organization wide double-sided copying policy (set the defaults of copiers and printers to print double-sided), reuse old paper as scratch paper, put company bulletins in electronic form (email), centralize files to reduce redundant copies, save files electronically versus hard copy, and donate old magazines to hospitals or other organizations;

? Packaging—order merchandise in bulk, work with suppliers to minimize packing materials, establish a reuse policy for cardboard boxes, implement returnable containers, reuse shredded newspaper as packing material;

? Equipment—use rechargeable batteries, reuse old tires for landscaping or pavement, install reusable filters, donate old furniture, sell obsolete equipment and computers;

? Organic waste—compost yard trimmings, choose low maintenance landscape designs, use mulching mowers;

? Inventory/purchasing—set up an area in the facility where employees can exchange used items, purchase more durable products, order in bulk to reduce packaging supplies, use a waste exchange program;

? Zero landfill options—food waste composting and energy recovery sites are two options for organizations considering zero landfill status.

3.7.3 Screening Alternatives

The process of creating waste minimization alternatives can generate hundreds of options. It would be very time consuming for the team to conduct detailed financial and operational feasibility evaluations on each option. A quick screening process can help to quickly identify the options worthy of full evaluations and possible inclusion in the waste minimization program. Additionally, non effective options can be weeded out, saving the team time and money in the evaluation process. An effective screening process should be based on the original goals of the project and at a minimum should examine:

? expected solid waste reduction (tons per year);

? expected start up costs;

? impact to waste removal costs ($ per year);

? impact to purchasing costs ($ per year);

? impact on employee moral;

? ease of implementation.

3.7.4 Analyzing and Selecting Alternatives

After trimming down the list of alternatives via the screening process, the remaining alternatives should be further analyzed to determine the best fit for the organization to minimize solid waste and hence include in the program. The analysis process focuses on identifying the benefits, costs, and drawbacks of each alternative. To accomplish this, each alternative is evaluated based on:

? impact on the program goal;

? technical feasibility;

? operational feasibility;

? economic feasibility;

? sustainability;

? organizational culture feasibility.

Technical and operational feasibility is concerned with whether the proper resources exist or are reasonably attainable to implement a specific alternative. This includes the square footage of the building, existing and available utilities, existing processing and material handling equipment, quality requirements, and skill level of employees. During this process, product specifications and facility constraints should be taken into account. Typical

technical evaluation criteria includes:

? available space in the facility;

? safety;

? compatibility with current work processes and material handling;

? impact on product quality;

? required technologies and utilities (power, compressed air, data links);

? knowledge and skills required to operating and maintain the alternative;

? addition labor requirements;

? impact on product marketing;

? implementation time.

When evaluating technical feasibility, the facility engineers or consultants should be contacted for input. In addition it is also wise to discuss the technical aspects with workers directly impacted by the change such as production and maintenance. If an alternative calls for a change in raw materials, the effect on the quality the final project must be evaluated. If an alternative does not meet the technical requirements of the organization, it should be removed from consideration. From a technical standpoint, the three areas that require additional evaluation are:

? equipment modifications or purchases;

? process changes;

? material changes.

From an economic standpoint, traditional financial evaluation is the most effective method to analyze alternatives. These measures include the payback period, (discounted payback period), internal rate of return, and net present value for each alternative. If the organization has a standard financial evaluation process, this should be completed for each alternative. The accounting or finance department would have this information. To perform these financial analyses, revenue and cost data must be gathered and should be based on the expectations for the alternatives. This is more complicated that is sounds, especially if a project will have an impact on the number the required labor hours, utility costs, and productivity, not to mention initial investments. A comprehensive estimation of the cost impacts (revenues and costs) per year over the life of the alternative is required to begin the analysis. The first step of the economic evaluation process is to determine these costs. These costs include capital costs (or initial investment), operating costs/savings, operating revenue, and salvage values for each waste minimization alternative.

3.8 Implementation and Execution of the Plan

A well developed deployment plan based on viable options will yield poor results if the plan is not executed properly. There is no such thing as“over-communication” when it comes to rolling out a new project or program. The three key components of a successful implementation and execution are following the deployment plan, communication, and recognizing the need to adjust in certain circumstances.

To facilitate the communication process, at a minimum, weekly progress meetings should be held with all key stakeholders. These meetings should focus on the status of each project versus the timeline and established goals. An agenda and the project timeline should be prepared in advanced and serve to lead the discussion. The task leader (as determined in the deployment plan) should take the lead role in discussing the status of each project or program. Any obstacles or delays should be discussed so that the team may determine solutions.

During the deployment process it is critical not to overwhelm employees with process changes. Effort should be taken to ensure that all employees are aware of upcoming changes, timelines, and the reasons behind the change. This can be accomplished with service talks, postings or newsletters in paychecks. All three options may be used to ensure that the message is heard and that employees are not confused and buy in to the programs.

In general, less effort is required for operational and process changes. These options can usually be

implemented in a much quicker fashion than equipment or material changes. A general outline of the scope of an implementation effort is provided below:

? Approve the project or program;

? Finalize the specifications and design for each alternative;

? Submit and gather bid requests and quotes (if necessary);

? Complete and submit a purchase order;

? Receive and install the equipment;

? Finalize operating and maintenance procedures;? Train affected employees;

? Start the project or program;

? Complete regulatory inspections;

? Track implemented project cost savings and waste reductions.

3.9 Program Validation

Many organizations require a validation process to ensure that projects and programs have met the goals that were set at the onset of the project. This includes validating the project or program installed at or below cost. It is operating within the expense and revenue limits, and it is achieving the waste reduction goals. Even if an organization does not require a validation process, it can be a very valuable tool for future planning processes to identify estimation errors occurred and take effort to correct them. Alternatives that do not meet the established goals or expected performance expectations may require rework or modifications. It is also critical to store warranties and contracts from vendors prior to the installation of the equipment. Also, the experience gained in implementing an option at one facility can be used to reduce the problems and costs of implementing options at subsequent facilities.

An alternative performance analysis should be completed for each equipment, process, or material change. The analysis provides a standardized method to compare project performance again estimates in terms of:

? project duration;

? implementation cost;

? operating expenses and revenue;? waste reduction volume;

? cycle time and productivity;? product or process quality;? safety.

3.10 Monitor and Improve Performance

After the waste minimization program has been implemented and validated it must be monitored on a periodic basis to ensure that it is still performing as planned and to make any necessary adjustments. This is a critical step of the six sigma process to ensure the successes from the assessment and team and sustained and supported. This includes monitoring the waste reduction amounts, operational and financial performance versus the goals. In addition, emphasis should be placed on continuous improvement to enhance current waste reduction programs and to identify new opportunities. It may be beneficial to conduct period waste assessments, facility walk-through, or employee interviews by the original waste reduction team to accomplish these goals. When evaluating the program, it is important to:

? keep track of program success and to build on past successes;

? identify new ideas for waste reduction;? identify areas needing improvement;

? document compliance with state or local regulations;

? determine the effect of new additions to the facility or program;

? keep employees informed and motivated.

In addition, considering reviewing the organization’s waste removal receipts and purchasing records on at least a quarterly basis is to ensure that the waste minimization program is working. New product or process changes should also be evaluated at the onset to ensure that the design minimizes

environmental impact. This is easily accomplished by adding “waste minimization review” to the new product or process checklist or standard operating procedure.

The waste minimization program is a continuing versus a one time project. Generally, the first waste assessment and implemented alternatives will target only the high volume waste streams. Once these high volume waste streams have been reduced, the team can shift its focus to lower volume waste streams. From a systems standpoint, the ultimate goal of the team is to minimize all input materials into the facility and by-products generated by the facility. The frequency in which the additional waste assessments are conducted will depend on the budget of the company. In general, organizations that conduct assessments one to four times per year have achieved paybacks. In addition, if there special circumstances that indicate the need for further review a waste assessment should be conducted, these special circumstances include:

? a change in raw material or product requirements;

? higher waste management costs;? new regulations;? new technology;

? a major event with undesirable environmental consequences (such as a major spill).

To be truly effective, an organizational culture of waste minimization must be fostered within the organization. Executive management must ensure this through repeated communications and acknowledgements for success stories from individuals or business units. This will make waste minimization an integral part of the organization’s operations.

3.11 Case Study

This case study is summarized from an original article published earlier [3]. In March 2006, a waste assessment was performed at a light manufacturing and assembly company located in Northwest Ohio with over $25 million in annual sales. The company had been privately owned since its inception employing over 100 employees on two shifts. The company has foreign subsidiaries and ships heavily to the Pacific Rim. The objectives of the waste minimization assessment were to define the various waste streams and to identify economically feasible options for the minimization of those waste streams. The facility was considering transforming into a zero landfill facility and the six sigma waste minimization process described in this article was applied.

At the time of the assessment, the company utilized six final waste containers. A compactor located at the rear of the building was used for general garbage, of which approximately 85 cubic yards (cy) per month were generated. An on-call, dedicated OCC (old corrugated container) trailer located next to the compactor was collected three to four times per month. Based on the areas targeted by the company and the results of the audit, several distinct areas presented opportunities to reduce collection costs in conjunction with decreasing the amount of material which goes to the landfill. The major areas included diversion of urethane flashing and soiled buckets from the dumpster, increased diversion of OCC, aggressive office paper collection, and the diversion of mixed plastic and label backing from the compactor.

The waste assessment team identified 14 major waste streams produced by the company. Of these 14 streams, nine of the streams were potentially recyclable. At the time of assessment, the company recycled OCC, shredded office paper, pallet waste, and metal turnings; the other potentially recyclable waste streams were disposed of in either the compactor or the urethane dumpster, both of which were being landfilled. By separating the potentially recyclable material from the waste streams, the company significantly reduced both the amount of material going to the landfill as well as disposal costs. Table 2 provides the resultant alternatives for handling

4. Conclusions

The overview of the waste assessment process and case study provided in this paper demonstrates that six sigma concepts can be applied in the solid waste management field to improve environmental quality, reduce waste, and increase company profitability. In addition, this paper provides a framework for other institutions across the world to duplicate the concepts and processes and adopt similar programs. Solid waste assessments based on six sigma concepts provide several benefits to businesses and colleges that include:

? enhanced cost savings and waste reduction(improved profitability);

? improved company images (green);

?sustained results through statistical monitoring and evaluation.

Education of college students though practical, real-world environmental work experience and trains them to become future environmental leaders.

References

[1] Municipal Solid Waste in the United States 2007 Facts and Figures, EPA-350-R-08-101, USEPA, Washington D.C., 2008.

[2] Q.L. Wang, B.S. Dong, B. Zhou, Q. Huang, The current situation of solid waste management in China, Journal of Material Cycles and Waste Management 8 (2006) 63-69.

[3] M. Franchetti, The solid waste analysis and minimization research project: A collaborative economic stimulus and environmental protection initiative in northwest Ohio, The Journal of Solid Waste Technology and Management 25 (2009) 88-94.

[4] Waste Minimization Assessment Manual, USEPA, Hazardous Waste Engineering Research Laboratory, Cincinnati, OH, 1988.

[5] J. Petek, P. Glavic, An integral approach to waste minimization in process industries, Resources, Conservation and Recycling 17 (1996) 169-188.

[6] W. Breyfogle, Managing Six Sigma—A Practical Guide to Understanding, Assessing and Implementing the Strategy That Yields Bottom Line Success, John Wiley & Sons, New York, 2001.

[7] P. Pande, R. Neuman, R. Cavanagh, The Six Sigma Way, McGraw-Hill, New York, 2000.