Pollution Prevention Through Systems Analvsis

Prepared for The Fifth World Congress of Chemical Engineering

San Diego, California July 14-18,1996

bY Irvin W. Osbome-Lee, Ph.D. Chemical Technology Division Oak Ridge National Laboratoryt

March 13,1996

Ihr submitted nmnusmk~I has been aurhorui by a colllractar of the US. Government under c ~ ~ l h a d DE-ACO5-96OR22464. Accordingly. rhe US. Gownarmr r&ns a nauxchrivc. r w i y f i e e license Io publish or reproduce he published form @this conrributim, or allow others to do so, for U. S. Govemmmtpurpascs.

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DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use- fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any spe- cific commercial product, process, or service by trade name, trademark, manufac- turer, or otherwise does not necessarily constitute or imply its endorsement, m r n - mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Table of Contents INTRODUCTION AND OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 POLLUTION PREVENTION (P2) , . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . 1

Defining p2 , . . . . . . . . . . , . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . , . . . , . . . . 1 Key Parameters in €2 . . . . . , . . . , . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

MaterialQuantities .................................................................. 1 Material Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Regulatory Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . , . . . , . . . . . . . . . . . . . . . . . . 2 P2 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . 2

P2 TOOLS . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 P20A Worksheet Method . . . . . . , , . . . . . . . , . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Level 111 P20As . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Systems Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . , . . . , . . . . . . . . . . , . . . . . . . . . . . . . . . . .3 Systems Analysis with FLOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

CASE STUDY: GROUTING OF MIXED WASTE . . . . . . . . . . . . . . . . . . . . . . . , . . . . . , . . . . . . . . . . . . , . . . . 4 SUMMARY . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , , . . . 5

List of Tables and Figures Table 1. The P20A Worksheet Method, Graded Approach . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . 3

Figure 1. Example representation of the flow down of pollution prevention from regulations to actual implementation in the DOE Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figure 2. The P20A Worksheet Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 3. Flow sheet simulation of a mixed waste grouting process with identification

of VOCs for potential recovery . . . . . . . . , . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 4. Flow sheet simulation of a mixed waste grouting process with recovery of VOCs . . . . . . . . . . . . . . . 6

List of Acronyms CAA CWA DOE DP FFCA ORNL P2 pollution prevention P20A pollution prevention opportunity assessment P2SA PPA Regs regulations RCRA TSCA WMES

Clean Air Act (42 USC 7401) Clean Water Act (33 USC 1251) United States Department of Energy Office of Defense Programs, United States Department of Energy Federal Facilities Compliance Act (42 USC 1301) Oak Ridge National Laboratory, located in Oak Ridge, Tennessee

Pollution Prevention and Systems Analysis Group, Chemical Technology Division, ORNL Pollution Prevention Act of 1990 (42 USC 1301)

Resource Conservation and Recovery Act (42 USC 6900 1) Toxic Substances Control Act (15 USC 2601) Waste Minimization Evaluation System, a prototype tool for developing and implementing a waste minimization plan, developed at ORNL by P2SA

Pollution Prevention Through Systems Analysis Irvin W. Osborne-Lee, Ph.D., Chemical Technology Division Oak Ridge National Laboratory

INTRODUCTION AND OVERVIEW There is a need to identify barriers that impede the implementation of pollution prevention (E) and to develop ways to eliminate them. On a broad scale, this includes such barriers as inflexible procedures, poor specifications, and the ' t~ong8t type of money. In industry, the potential expense and the complexity of processes together serve as a banier to the exploration of P2 opportunities that involve significant process change. This paper addresses the latter barrier and presents systems analysis, including process modeling and analysis, as a potential solution.

An integrated systems approach for evaluating potential P2 process modifications is presented. This approach combines elements of systems analysis, process simulation, decision analysis, life-cycle cost analysis, and risk analysis to score process modifications. Examples given show how chemical process technologies, including waste treatment processes, can be amfigured, scored, reoonfigured, and then compared with relative ease. This method serves as a natural follow- on to P2 opportunity assessments (P20As), which have gained popularity in the U. s. Department of Energy (DOE) arena, and allows opportmties to be evaluated and ranked in terms of their P2 potential, viability, and potential return on investment.

POLLUTION PREVENTION (P2)

Defining P2 Amding to the U.S. Environmental Protection Agency, P2 is reducing or eliminating the creation of pollutants at the source through the wellconsidered use of materials, processes, or practices.' Included are practices that: (1) reduce the use of hazardous or nonhazardous materials, (2) reduce energy use, (3) reduce water usage, (4) reduce the use of other resources, and (5) protect natural resources through conservation or more efficient use.

Hence, P2 can entail either product changes, process modifications, or changes in operating practice. The Pollution Prevention Act of 1990 defmed P2 in terms of a waste management hierarchy, wherein activities are given preference based on the following ranked categorization: (1) eliminate at the source, (2) reuse or recycle the waste, (3) treat the waste, or (4) dispose of the waste safely. It is clear that a great deal of focus has been placed on P2 as a frontend, preemptive measure, resulting in a concentration of efforts at source reduction. Yet, opportunities for P2 exist at every stage of the hierarchy. While the ultimate aim of source elimination is a highly desirable goal, many process modifications that could have the effect of "preventing pollution" are not considered.

Key Parameters in P2 To accomplish P2 requires one to have a knowledge of key process parameters. By process is meant any existing or planned operation or activity which generates waste or pollution of the air, water, or land. Every process has some product, whether material or not., and may generate some pollution. Whatever the process, certain key quantities must be known.

Material Quantities A knowledge of material quantities, mass and volume, are required. This should include baseline production rates (for the product) and emissions release rates. Also, annual production and release rates are needed. Material balance calculations, normally used on process flow sheets, are essential for this idormation. For complex processes, requiring detailed flow sheets, process simulation can greatly facilitate calculations.

Osborne-Lee Pollution Prevention Through Systems Analysis

Material Characteristics Characterization of emissions is important. Contaminant concentrations are obviously important, but so also is hazard information such as toxicity, carcinogenicity, radioactivity, reactivity, and explosivity.

Regulatory Limits Regulatory limits are important, but not just as a minimal performance goal. These limits can serve as a useful benchmark by which to measure P2 progress.

P2 Index Finally, a very useful parameter in measuring P2 progress is the pollution index. This index may be defmed in several ways, but it should be defmed in a way that provides a meaningful measure of P2 performance from year to year. Two examples of P2 indices, denoted here as In, are as follows:

Ipz = mass sum of pollutants released per unit product per year. 0 In = product of the mass and toxicity for each pollutant, summed for all pollutants for the year.

The change in either of these quantities fiom a previous year, - (& &e,+ow, is a measure of the pollution prevented that year. The index may also be normalized based on product generation. Alternatively, the P2 index may be defmed in terms of feed materials used rather than waste or pollutants produced. For some industries, this “materials use” approach is easier to apply and more meaningful than the “waste production” approach, considering the entire life- cycle of a material’s use. Further discussion on choices of indices for measuring P2 progress may be found elsewhere.*

P2 TOOLS P2 has evolved into a prime strategy for industry to meet environmental, fiscal, and worker-safety obligations. As a result, a variety of program planning, opportunity identification, and implementation tools have been developed. P2 techniques should be used to minimize the toxicity and quantity of wastes and pollutants resulting from technology applications. P2 can be applied to normal operations at corporate or government facilities, whether engaged in research, production, or even decontaminaton and decommissioning and environmental restoration. Over the past several years, sisIuficant reduaions of wastes and pollutants have been reported as a result of the application ofP2 measures, resulting in substantial savings in both operating and clean-up costs.

A variety of resources for p2 have appeared in recent years, from data bases to methodologies to computer-based tools. These tools are applicable at different stages of the flowdown from regulations to project implementation. As an example, Fig. 1 depicts the way in which laws flow down to implemented projects in the DOE complex. Also shown are some tools, including systems analysis, and where they are finding application. A recent publication provides a summary of the laws and Presidential Executive Orders relevant to P2.3

While systems analysis as a tool for P2 is the primary focus of this paper, it is illustrative to understand the role of other types of tools in p2 and their relationships to systems analysis. One particularly important tool, briefly described below, is the P20A Worksheet Method.

PZOA WORKSHEET METHOD A P20A is a comprehensive examination of operations at a facility or for a process with the goal of minimizing waste products. A worksheet method for P20A is used at many DOE sites. This approach, derived from the DOE Process Waste Assessment Model Plan, is based on a set of ten worksheets. Using a graded approach, three sets of worksheets can be used, depending on the depth intended for the P20A (see Table 1).

Osborne-Lee Pollution Prevention Through Systems Analysis

:.,...:.:

s*a or F a ~ ~ * t y

..... S.$ Re se

Site Individual PZ Departmental Plans

P2 Opportunity Assessments

PZ Project Im plem entation

Worksheet Method

Systems Analysis

Fig. I. Example representation of the flow down of pollution prevention from regulations to actual implementation in the DOE Complex. Application areas are shown for some P2 tools developed recently at Oak Ridge National laboratory (ORNL).

Level 111 P2OAs The full P20A has ten worksheets, as shown in Fig. 2. It helps in building the P20A team and takes the team through the procedure of identifying process boundaries, developing a process description, and creating a process flow diagram. The team is led to determine data requirements and develop a material balance summary, in which products and pollutants are identified along with their origin, fate, and cost. A key phase of the P20A is that of option generation, in which €2 ideas are generated and documented for further consideration. Options are then elucidated, categorized, and screened using research as needed. Options are next evaluated on the basis of cost estimations, before a weighted sums approach is used to rank competitive options. Finally, a checklist is used in developing the final report.

Systems Analysis Systems analysis is a problem-solving method in which a “system” encompassing one or more processes is studied in stages. Analysis begins at the top-most level, that of least detail, and proceeds into more detail as needed to understand the problem. This method has proven very useful in understanding complex systems and finding solutions to complicated problems. ORNL’s Pollution Prevention and Systems Analysis group (PZSA), Chemical Technology

Table 1. The P20A Worksheet Method

Graded Approach

Average Effort Worksheets

P20A Type (Hours)” Applicable

Level I 40 3

Level II 60 5

Level 111, Full I20 IO aAdditional effort may be required for complex processes with multiple alternatives.

Osbome-Lee Pollution Prevention Through Systems Analysis

ORNUDWO Be-3777

Fig. 2. The P2OA Worksheet Method. The full assessment has ten worksheets. The asterisk (*) indicates activities for which process analysis and systems analysis as a whole, can have a large positive impact.

Division, has used systems analysis to provide technical support for difficult decisions, primarily in the area of nuclear waste n~.magement."~*~

Systems Analysis with FLOW FLOW7 is a steady-state process simulator developed by P2SA to make systems analysis easier to apply to complex problems. FLOW calculates many useful quantities, such as material balances, performance, cost, health risk, and disposal acceptability. Material balances are essential in evaluating P2 opportunities identified by P20As, as are performance and cost. Risk should also be considered, especially for high-profile activities or those with a high degree of public satiny. Disposal acceptability is also important, because there will likely always be some waste that requires disposal. This is especially true for processes dealing with waste as feed streams, as in waste management.

Many alternative solutions may be quickly examined using this computer-based analysis tool. FLOW is an object- oriented program that calls on programs as models are needed to simulate processes. Other programs are used in FLOW to perform special tasks, such as the calculation of risk for radionuclides or for hazardous chemicals. FLOW has already been used to solve problems of national importance, such as the problem of which treatment technologies to use for certain mixed wastes on the Oak Ridge Reservation. Figure 2 shows where systems analysis is most useful in the P20A process. An example applying systems analysis, using FLOW, is presented in the following section. Grouting, a waste management technology, has been chosen as the process.

CASE STUDY GROUTING OF MIXED WASTE Grouting is the fixation of waste using a blend of cement with combinations of clays, fly ash, or blast furnace slag. It is a simple process: Material to be grouted is (1) combined with grout blend components, (2) mixed, and (3) allowed to set and cure. Exms water is removed off the top of the grouted material once it has settled. A P20A conducted for this process quickly identifies the loss of volatile organic compounds (VOCs) as a P2 opportunity. A simple flow diagram would serve to provide a material balance. However, to address the question of lost VOCs, extra detail is needed (see Fig. 3). Using FLOW, we can easily represent the process in such a way that VOCs can be tracked and their impacts on performance, risk, and cost can be evaluated.

Osbome-Lee Pollution Prevention Through Systems Analysis

Waste Grou t inq Process Model

i Groutformulator i

; e 11-

<..............................A ........... Cheml?isk<UOCs> LostVUL;s '

1 x0.5 FixableUaste x 2 -4 spl i 1 t er f ToDe-y*p-;r 'tier TOSDlit

i ExcessH20ei~m .......... I i . ~ c o s t e r o u t

..................... L i Wast e<+UOCS> . . Input ToGrout .& i a :

........................... . . . . ........... ,+! ; UOC-Flash . .

urou- e c w a s x er or m ChernRisk

GROUTPBFLU

Fig. 3. Flow sheet simulation of a mixed waste grouting process with identification of VOCs for potential recovety. Risk to workers and the public is notable for representative contaminated soils studied. Simulation was performed with FLOW, developed at ORNL.

The scenario of Fig. 3 was built by dragging icons kom the menu bar at left into the work space and connecting them. Following quick and simple data entry, this simulation was completed and then could be executed. In this brief example, we focus on the health risk both to workers (on-site) and the public (off-site). We considered the case of soil contaminated with hazardous constituents, including VOCs, other organics, metals, and radionuclides. This mixed waste we considered for treatment by grouting in a facility that would be built to process about 30 kg per week of this material over a period of 15 years. The risk estimated because of normal releases characteristic of the unit operations involved was significant, primarily because of VOCs, which are completely lost in the scenario, as shown in Fig. 3. A modification of the Fig. 3 scenario, in which the VOCs would be recovered, is shown in Fig. 4. For this case, a trap and condenser were added to the process, thus allowing recovery of 99.9% of the VOCs. The risk was reduced by a substantial amount with only a minimal increase in the cost of the facility.

SUMMARY The evolution of €2 as a means to economic and environmental viability has highlighted a need in industry for a means to rapidly explore and evaluate alternative process scenarios. Systems analysis has been presented as an additional P2 tool that can work hand in hand with P2 opportunity assessment. The power of insight of systems analysis and the usefulness of process simulation were demonstrated through an example of waste grouting. Combining systems analysis with EOA, process options that lead to affordable, if not lucrative, reductions in adverse environmental impact can be identified and evaluated in a timely and an economical manner.

Osbome-Lee Pollution Prevention Through Systems Analysis

ORNUDWG 96

Waste G r o u t i n g P r o c e s s Model

cs LOStUOCS FixrblcWartc

RadRisk . . ~ - - -

LnernKisK

ToReclaarati on

Recl ai medUOCs

InputToGrwt .& ; ,................. 1 GroutMixer 1 uruarcrer WasteH2QFr orn(3rout

WACcheck Groutcd~astcForln -

-. -. .

GROUTP2RFLU

Fig. 4. Flow sheet simulation of a mixed waste grouting process with recovery of VOCs. Risk to workers and the public i s greatly reduced for the representative contaminated soils studied, with a minimal cost increment. Simulation was performed with FLOW, developed at ORNL.

REFERENCES 1. U.S. Environmental Protection Agency, Facility Pollution Prevention Guide, EPA/600/R-92/088, May 1992. 2. M. Malkin, J. N. Baskir, and J. Spooner, “Issues in Facility-Level Pollution Prevention Measurement,”

Environmental Progress, 14 (4), page No. 240, November 1995. 3. J. S. Bridges, and N. T. Hoagland, “Using Pollution Prevention Tools for Compliance in the Federal Community,”

Environmental Progress, 14 (4), page No. 273, November 1995. 4. J. J. Ferrada, et al., Preliminary Process Simulation and Analysis of GMODS: Processing of Plutonium Surplus

Materials, ORNLRM- 13 109, Oak Ridge National Laboratory, Oak Ridge, Tennessee, January 2,1996. 5. J. J. Ferrada, et al., Systemshalysis of Oak Ridge Reservation Mixed Waste Treatment Alternatives, OFWL/TM-

12842 (draft), Oak Ridge National Laboratory, Oak Ridge, Tennessee, 1994. 6. J. J. Ferrada, et al., T. D. Welch, I. W. Osborne-Lee, and J. W. Nehls, Jr., “Using Systems Analysis to Improve

Decision Making in Solving Mixed Waste Problems at the Oak Ridge National Laboratory,” Proc. VIP 52, May 10-12, 1995, Washington, D.C., Air & Waste Mgmt. Assoc., Pittsburgh, 1995.

7. J. J. Ferrada, J. R. Jackson, and V. L. Phuong, “Process Simulation in Waste Management,” hoc. Waste Management and Environmental Restoration Conference, San Juan, Puerto Rico, April 1992.