°000145

CanonieEnvironme: d.

ReportStabilization Design Study

Gould, Inc.Cercla SiteMultnomah CountyPortland, Oregon

Submitted To:

NL Industries, Inc.Hightstown, New Jersey

TABLE OF CONTENTS(Continued)

PAGE5.6 Other Tests 14

5.6.1 Slump Tests 14

5.6.2 Penetrometer Tests 146.0 QUALITY ASSURANCE/QUALITY CONTROL 16

7.0 SITE COMPARISON SAMPLE RESULTS 17

8.0 STABILIZATION PLANT DESIGN 18REFERENCES

TABLES

FIGURES

APPENDICES

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TABLE OF CONTENTS

PAGE

LIST OF TABLES 1

LIST OF FIGURES iii

LIST OF APPENDICES iv

1.0 INTRODUCTION 1

2.0 SUMMARY 2

3.0 SELECTION OF STABILIZATION TECHNOLOGY 4

4.0 SUMMARY OF PREVIOUS WORK 5

4.1 FS Stabilization Work 5

4.2 Bench-Scale Studies 6 vj

5.0 PILOT-SCALE TEST WORK 7

5.1 Materials to be Stabilized 85.2 Pilot Stabilization Program 85.3 Stabilization of Aggregate-Size Material 9

5.3.1 Results for Composite Materials 9

5.3.2 Results for Soils 10

5.4 Results of the Second Set of Tests 115.4.1 Formulations Tested 115.4.2 Results for Composites 115.4.3 Results for Soils 12

5.5 Physical and Chemical Test Results 125.5.1 Long-Term Leaching Tests 125.5.2 Permeability 135.5.3 Wet/Dry Test 135.5.4 Potential Reactivity of Aggregates Tests 14

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STABILIZATION DESIGN STUDY

1.0 INTRODUCTION

This report fulfills the requirements of the March 31, 1989 Consent Decreeand of the Stabilization Design Study described in the Work Plan Schedule(Task 6) for the Predesign Studies for the Gould site. This report hasbeen reissued to include long-term stabilization data not available inApril 1990. This report supersedes the Stabilization Report issued inApril 1990.

The studies have been performed on selected Site Reference Materials (SRM),which do not contain sufficient lead to be recycled, and do not pass theExtraction Procedure Toxicity Characteristics (EP Tox) test for lead.These materials include contaminated soils, which exist on the site, and

^s ebonite and other waste products from the treatment process that has beendeveloped to produce recyclable materials from the waste.

Screening, physical, and chemical tests have been performed on multiplemixes using locally available materials such as cement and fly ash. Thesetests have been performed at the bench and pilot scales to obtain a for-mulation that will meet the long-term requirements for on-site disposal ofthe waste below grade and in the existing water table.

This report contains a complete description of the test work conductedduring the stabilization program, including test data and interpretation oftest results. A binder formulation has been developed that will successfully stabilize the materials to meet and exceed the minimum physical andchemical criteria determined for on-site disposal and will improve withaging. Canonie recommends that the formulation be used to stabilize thematerials that do not pass the EP Tox test for lead and will remain on theGould site following remediation.

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2.0 SUMMARY

The site materials and the waste products from the treatment process at theGould site can be successfully stabilized using the standard cement/poz-zolan treatment methods normally used for the stabilization of metals insoils. The physical and chemical characteristics of the stabilizedmonolith are expected to improve with aging, such that the monolith can bedisposed on-site beneath the water table without creating an environmentalhazard.

The pilot test program demonstrated that a mix of about 14 percent PortlandCement Type l-II, 25 percent cement kiln dust, and 35 percent water will ,result in a solid matrix with an unconfined compressive strength of at ^least 250 pounds per square inch gauge (psig) and an EP Tox for lead ofless than 2 parts per million (ppm).

As shown in Table 1.1, the stabilized monolith will have a low permeability(10 to 10 cm/sec) so that ground water will not invade it. It isresistant to mechanical spall1ng and chemical breakdown and is stable inthe presence or absence of ground water. These characteristics will pre-serve the mechanical integrity of the monolith in the near and long term.

Leaching of lead from the monolith into the ground water, as shown onFigure 1, is initially small and will decline with time. Lead solubility .jwill decrease as the lime base is leached out by ground water moving overthe surface of the monolith. As shown in Table 2.1, the physical strengthof the monolith increased from 255 psig to 703 psig with time. The resultsindicate that the chemical and physical stability of the monolith willimprove with aging.

The suggested binder formulation can be used to stabilize any of the sitematerials (soils or waste), and no special materials handling or stockpil-ing procedures are required. The stabilized matrix has acceptable handlingcharacteristics and setting time such that it can be managed for disposalwithout special scheduling considerations.

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Canonie Environmental Services Corp. (Canonie) has reached these conclu-sions through the performance of bench- and pilot-scale test work. Thework was conducted on samples from the site, including soils and furnaceproducts, and materials from the process developed by Canonie to treat thesite wastes. The initial selection of binder formulations was based on thesuccessful results of the test work completed for the Feasibility Study(FS).

The successful formulation was reached by a sequential program of screeningand physical and chemical testing by which only the most promising mixeswere advanced to the next step. Bench-scale tests were conducted usingcement, cement kiln dust, and lime kiln dust binders with various mixratios and amounts of water added. The criterion used to select thesuccessful formulation to be advanced to the pilot studies was the EP Toxtest for lead.

In the pilot studies, the evaluation criteria were expanded to includeslump tests for mechanical handling characteristics, and unconfinedcompressive strength tests for physical strength, as well as the EP Toxtest for lead. Mixes containing fly ash, which are used commercially, werealso evaluated. This test work led to the final selection of a formulationcontaining cement and cement kiln dust, which can stabilize all of thewaste at the site. Final tests on long-term physical and chemicalstability were conducted using this formulation.

The stabilization process can be conducted using standard equipment andprocedures as described in the Site Investigation Report (Canonie, 1989a).All materials can be obtained locally, and no special problems are an-ticipated for the completion of site remediation.

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3.0 SELECTION OF STABILIZATION TECHNOLOGY

Stabilization of contaminated materials involves the immobilization ofcontaminants in a form which is physically and chemically compatible withthe disposal site. The stabilized material should have suitable charac-teristics for handling during processing and disposal and prevent themigration of contamination over the long term, if not In perpetuity.

Stabilization technology has been successfully applied to a variety ofwaste materials (Malone et al, 1980). As shown in Table 3.1 five cate-gories of processes have been used to stabilize a wide range of wastematerials, including metals, toxic organics, resins, and radioactivewastes. The technologies and procedures most applicable to the Gould siteare the cement and pozzolan-based systems used for stabilization of metalsin soils.

In the cement and pozzolan-based systems, the wastes are incorporated intothe cement matrix and, in some cases, undergo physical-chemical changesthat further reduce the mobility of contaminants in the waste-cement ma-trix. Typically, metal hydroxide precipitates are formed. Varying amountsof fly ash, kiln dust, sodium silicate, bentonite, or proprietary additivesare added to prevent contaminant migration by sorption and/or precipita-tion. These constituents are required because some metals such as nickel,lead, and zinc are amphoteric and dissolve at the high pH, which prevailsin the cement hydration reaction.

Formulations that have been used to stabilize lead-bearing soils at othersites are listed in Table 3.2. Because of this prior experience, and theprevious work conducted during the FS for the Gould site (Games & Moore,1988), cement/pozzolan-based technology was selected for development test-ing for the stabilization of waste materials at the Gould site.

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4.0 SUMMARY OF PREVIOUS WORK

During the FS (Dames 4 Moore, 1988) a preliminary set of tests was con-ducted on lead-contaminated soils and sediments from the Gould site, usingthe cement and pozzolan mixes normally used for the stabilization of metalsin soils. Successful formulations were selected on the basis of theirability to cause the stabilized material to pass the EP Tox test for lead.

The same formulations that were successful during the FS programs weretested on contaminated soils and furnace products, and waste productsgenerated during the bench-scale test work on the recycling treatmentprocess. Various combinations of binders and water additions were tried,and successful formulations were selected on the ability to pass the EP Toxtest for lead. The more successful formulations were advanced to the nextlevel of testing (pilot testing) for more detailed screening of physicaland chemical characteristics and long-term stability of the stabilizedwaste.

4.1 FS Stabilization Work

The results of the preliminary stabilization work conducted by WestonServices, Inc. (Weston) are summarized in Table 4.1. Further details onthis work can be found in the FS for the Gould project.

Weston conducted the work on samples of soil and sediment from the Gouldsite. The untreated materials had very high levels of EP Tox for lead (710ppm) for the untreated soils and moderate levels (24 ppm) for the sedi-ments. Successful binders for the soil included cement kiln dust (EP Toxfor lead of 3.5 ppm) and lime kiln dust (EP Tox for lead of 1.0 ppm). Bothbinders also were successful in stabilizing sediments (EP Tox for lead ofless than 1.0 ppm). Canonie used the binder formulations that were suc-cessful in the Weston studies as a starting point for the bench-scalestudies.

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- J4.2 Bench-Scale Studies

The primary evaluation criterion during the bench-scale test work was theEP Tox value for lead of the stabilized material. The binders investigated

F in this test work included cement, lime kiln dust, and cement kiln dust.Various mixes of these binders were tried on process waste products, fur-nace products, soils and sediments from the Gould site, and soils andsediments from the Rhone-Poulenc site. Test results are summarized inTable 4.2. Further details on the work are presented in the August 1989Bench-Scale Test Results report (Canonic, 1989b).

n The bench-scale test program demonstrated that all of the site materials iJ ~ and process wastes could be stabilized to pass the EP Tox test for lead^ • using cement/pozzolan-based technology. EP Tox values for lead of less.1 _ than 1 ppm were obtained for ebonite fines, furnace matte, Gould soils, and

Rhone-Poulenc soils. The soils from the Rhone-Poulenc site appear to beeasiest to treat, probably because of the bentonite content.

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5.0 PILOT-SCALE TEST WORK

The pilot level of testing was designed to collect the information neededto select a formulation for stabilization of the waste materials that w i l lbe left on the Gould site following remediation. Test work was conductedon the successful formulations developed during the bench-scale testprogram and on formulations used commercially to stabilize soils contami-nated with lead.

Previous tests used only the EP Tox test for lead as the criteria forselecting successful formulations. In the pilot test work an additionalscreening test (unconfirmed compressive strength) was used to verify thatthe mix meets the physical requirements for on-site disposal. Additionaltests were performed on the optimum mix to verify that the stabilizedmaterial has the characteristics that make it physically and chemicallystable in the long term.

The program demonstrated that a mix of approximately 14 percent PortlandCement Type 1-11, 25 percent cement kiln dust, and 35 percent water wassuccessful in stabilizing soils and waste products crushed to pass 1/8-inchtop size. As shown in Table 1.1, this formulation meets all the require-ments for physical strength and long-term stability for on-site disposal ofthe stabilized monolith. In two of these tests -- unconfined compressivestrength [American Society for Testing and Materials (ASTM) C39] and long-term leaching [American National Standards Institute (ANSI) 16.1] -- thedata indicate that the physical and chemical characteristics of the stabi-lized monolith will improve with time. A complete list of analytical datafrom the test program is presented in Appendix A.

The test data were collected on a composite mixture of site and processwastes and on samples of contaminated surface soils. Stabilization wassuccessfully achieved for each of these materials using the same binderformulations, indicating no special excavation or material-handling proce-dures will be required during site remediation.

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5.1 Materials to be Stabilized

The Bench-Scale Test Program defined the treatment process that can be usedto produce recyclable materials from the waste at the Gould site. Thisprogram identified the quantities and characteristics (size, moisturecontent, etc) of the SRM and the wastes produced by the treatment process.

It was assumed that the waste materials will be stabilized as they aregenerated during treatment operations and that the soils can be stockpiledand blended with the plant wastes or stored and handled separately. Thepilot test work was conducted on a composite of soil and treatment wastesand on separate samples of soil from the Gould and Rhone-Poulenc sites to idetermine if these materials should be stabilized together or handledseparately. The distribution of site materials described in the compositesample, shown in Table 5.1, was based on the distribution of materialsprojected in the Bench-Scale Test Report.

5.2 Pilot Stabilization Program

The objective of the pilot-scale test program was to select and demonstratesatisfactory performance of a binder formulation that can be used tostabilize the materials at the site. A detailed review of the programgoals, specifications, and quality assurance/quality control procedures arepresented in Protocol 13 in Appendix B. ^,

The first set of tests was conducted on aggregate-like material having a1/2-inch top size that was expected to be generated during the treatmentprocess. Following stabilization, this material was crushed to pass 3/8inch as required by the Environmental Protection Agency (EPA) test method#1310, paragraph 7.9. Because of the top size used in the EPA Test Proto-col, a second set of tests was conducted on materials crushed to pass 1/8-inch top size prior to stabilization. The amended test protocol describingthese tests is presented in Appendix C.

Chemical and physical evaluation tests were used to screen the results ofthe binder mixes used and to advance the successful formulations to the

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next level of testing. The principal screening tests were the unconfinedcompressive strength tests and the EP Tox test for lead. Subsequent testswere performed on successful formulations to evaluate the long-term chemi-cal ana chysical effects of stabilization and to evaluate the material -handling characteristics of the stabilized mass.

5.3 Stabilization of Aggregate-Size Material

Table 5.2 describes the waste materials to be stabilized. Of these mate-rials, the matte and the Gould surface soils are likely to be the mostdifficult to stabilize because of the high lead content and high leadEP Tox values. The Rhone-Poulenc surface soils do not requirestabilization.

5.3.1 Results for Composite Materials

Initial pilot tests on composite materials containing matte were run usingthe binder formulation, which had been successful in the bench-scale testson matte materials. The detailed results of these tests are compared withbench-scale results in Table 5.3.

Stabilization tests performed on composite materials using cement kiln dustand lime kiln dust binders did not meet the criterion of unconfined com-pressive strength. Strengths ranged from 11 to 23 psig compared to the 50psig requirement. Strengths achieved using cement kiln dust and lime kilndust binders were comparable. It is likely that the required compressivestrength would have been reached if cement had been added to the mix.

Triplicate analyses for EP Tox for lead were performed on one samplestabilized with lime kiln dust. This sample passed the EP Tox test forlead, having values between 2.5 and 4.0 ppm compared to the 5.0 ppmstandard. When the pilot data are compared with the bench-scale data onmatte stabilization, it becomes apparent that the particle size does nothave a significant effect on the ability to stabilize the compositematerial. Stabilized matte at -20 mesh had a lead EP Tox of 0.5 ppm andthe matte composite at 1/2 inch had an EP Tox of 2 to 4 ppm for lead. It

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appears that the matte material, which constitutes the majority of thematerial to be left on-site, will respond favorably to the stabilizationprocess without an excess amount of pre-preparation.

5.3.2 Results for Soils

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A similar set of tests was run on soil samples from the Gould and Rhone-Poulenc sites. Both soil samples contained large-size trash components(rocks, cement, etc) with the Rhone-Poulenc sample having more trash (70percent by weight) than the Gould sample (20 percent by weight). Theoversize was not screened out prior to conducting the pilot stabilizationtest work, and the entire sample was crushed to a top size of 1/2 inch.Details of the test results are shown in Table 5.4 for Gould soils and inTable 5.5 for Rhone-Poulenc Soils.

The stabilization tests performed on soils demonstrated that the unconfinedcompressive strength requirement was reached using a cement binder. Valuesbetween 480 and 2,000 psig were obtained compared to the 50 psig targetvalue. The mix of Gould soil and cement kiln dust fell apart when it wasextracted from the mold, whereas the mix of Rhone-Poulenc soil with cementkiln dust reached compressive strengths of 335 to 500 psig. The differencebetween the two soils may be caused by the larger amount of bentonite clayin the Rhone-Poulenc sample.

The EP Tox values for lead in the stabilized material were not significant-ly different from the feed materials. As shown in Table 5.4, the stabi-lized Gould soils had a lead EP Tox between 85 and 130 ppm compared to 140ppm for unstabilized material. The untreated Rhone-Poulenc surface soilshad a lead EP Tox of 1 ppm, which is significantly below the 5 ppm targetlevel.

The results of the tests on the soils indicate that a combination mix ofcement for strength and cement kiln dust for chemical immobility will berequired to stabilize the soil and wastes at the Gould site.

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5.4 Results of the Second Set of Tests

When stabilized material at 1/2-inch top size is crushed to 3/8 inch forthe EP Tox test, new waste surfaces are exposed at which leaching of thecontaminant can occur. To overcome this problem, Canonie conducted a finalset of tests on materials which had been crushed to 1/8-inch top size. Inthis test work, mixes of different binding agents were tried to develop oneformulation that will stabilize all the materials at the site, which isdesirable from an operations standpoint.

5.4.1 Formulations Tested

The first set of tests indicated that a combination of binder additiveswould be required to achieve the unconfined compressive strength and leadEP Tox values desired for the stabilization matrix. In the bench-scaletests, cement kiln dust had been successful in stabilizing matte, andcement had been successful in stabilizing Gould soils. It was anticipatedthat a combination of cement and cement kiln dust should be able to stabi-lize a composite of these materials.

Canonie contacted Peoria Disposal Company (PDC) in Peoria, Illinois, wherestabilization of lead-bearing wastes is conducted on a commercial basis.PDC recommended the addition of Type F fly ash to the mix, since thismaterial contains a high concentration of silica, which may immobilire thelead as lead silicate. It was also recommended that a small amount offerrous sulfate should be added to the water in the mix to assist in thechemical immobilization of lead. Canonie incorporated these recommenda-tions into the tests. A Type C fly ash, which has a lower silica content,was also tested for the sake of comparison. The chemical composition ofthese binders is presented in Table 5.6.

5.4.2 Results for Composites

Test results on mixes of composite materials made up with the new formula-tions are presented in Table 5.7. Of the three formulations tested all

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attained the required compressive strength, and one (cement plus cementkiln dust) met the EP Tox requirements for lead.

Compression strength increased from 255 psig to 740 psig by adding fly ashto the mix. The fly ash formulations, however, yielded EP Tox values forlead of between 11 and 90 ppm, with the high silica fly ash having thepoorer result. The cement plus cement kiln dust formulation had an EP Toxvalue for lead of 1.35 ppm and a compressive strength of 255 psig.

5.4.3 Results for Soils

Test results on soils are presented in Table 5.8. Of the three formula-tions tested, all passed the unconfined compressive strength criterion and s-Jtwo passed the EP Tox test for lead. The compressive strength resultsranged from 630 psig to 1,400 psig with the higher numbers, as before,being obtained with the fly ash mixes. The high silica fly ash mix failedthe EP Tox test for lead with a value of about 16 ppm. The low silica/highlime fly ash mix gave the best combination of compressive strength (1,400psig) and the EP Tox for lead (0.36 ppm). The cement/cement kiln dust mix,which was successful with the composite materials, had a compressivestrength of 630 psig and an EP Tox for lead of 1.16 ppm.

5.5 Physical and Chemical Test Results

The samples of composite materials and soils that were stabilized withcement and cement kiln dust were advanced to the final round of testing todetermine the long-term physical and chemical characteristics. A detaileddescription of the objectives and procedures for these tests is presentedin Protocol 13 in Appendix B.

5.5.1 Lono-Term Leaching Tests

The long-term leaching tests were performed on composite and soil materialsaccording to the test specifications presented in ANSI 16.1. The compositematerial was run in duplicate. Test results are provided in Tables 5.9 and5.10.

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The composite material had a significantly higher extraction of lead in thewater (3.6 ppm) than the stabilized soil (0.2 ppm). In both cases, how-ever, the concentration of lead in the water continued to decline as thealkalinity dropped below pH 11.0 after 48 hours. The implication is thatthe lead forms an amphoteric compound at high pH, which results in itsdissolution. The lead is likely to dissolve when the ground water firstreacts to the presence of the stabilized monolith. The amount dissolved,however, is not expected to exceed the EP Tox value for lead.

As shown on Figure 1, the solubility will decrease in the long term andlead will remain insoluble and immobile. This condition is expected toprevail as long as the monolith maintains its physical integrity and theground water permeation remains negligible.

5.5.2 Permeability

To restrict the flow of ground water through the monolith, the stabilizedmatrix should have a permeability of one or more orders of magnitude lessthan the surrounding soils. According to measurements made by Dames &Moore during the RI/FS, the permeability of soils in the area is between

-2 -310 and 10 centimeters per second (cm/sec) (Dames & Moore, 1988). Asshown in Table 5.11, all of the stabilized materials had permeabilities of

-410 cm/sec or less. Consequently, it is anticipated that ground waterwill flow more readily around the stabilized monolith, rather than throughit.

5.5.3 Wet/Drv Test

Wet/dry tests were carried out to determine if alternative drying andwetting of the stabilized monolith will lead to spall ing and physicalbreakdown. A sample will fail this test if the cumulative weight lossexceeds 30 percent.

The test results for the stabilized composite and soils are presented inTables 5.12 and 5.13. The data indicate that minimum weight loss (0.055percent for the composite and 0.019 percent for the soils) was encountered.

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In addition, as shown in Table 2.1, the unconfined compressive strength ofthe monolith increased significantly during the wet/dry tests, indicatingthat the mechanical strength of the monolith has been shown to improve withtime.

5.5.4 Potential Reactivity of Aggregates Tests

Potential reactivity tests were conducted according to ASTM C289-87. Thesetests are designed to determine if an aggregate material is innocuous,potentially deleterious, or deleterious to the environment. The classi-fications used in ASTM C289-87 to categorize materials are reproduced inFigure 2. As shown in Table 5.14 and Figure 2, the stabilized Gould mate-rials will be classified as innocuous and do not constitute a hazard to the jenvironment.

5.6 Other Tests

Other tests were conducted to investigate the material-handling charac-teristics of the stabilized waste and the rate of attainment of compressivestrength. These data are needed to define the operating conditions andtime available for handling and disposal of the stabilized matrix.

5.6.1 Slump Tests

Generally a slump of between 3 and 5 inches gives a stabilized matrix with ^/enough plasticity that it can be pumped and cast into blocks, or a slab,without draining off excess water. Slump tests were run on all the pilottest runs and are summarized in Table 5.15. The selected optimum composi-tion had a slump of 4.5 inches making it suitable for handling and disposalby the methods selected in the Site Investigation Report.

5.6.2 Penetrometer Tests

Penetrometer tests were conducted on each stabilized matrix to determinethe rate of setting of the cement to achieve a minimum compressive strength

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Jof 50 pounds per square inch (psi). Test results are presented in AppenaixA and summarized in Table 5.15.

The test results indicate that minimum compressive strength for the select-ed formulation occurs in 48 hours after preparation. This data w i l l beused during the remedial design phase of the project to schedule materialsinto and out of the stabilization area for final on-site disposal.

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