cognis - soil remediation investigation - … ii traatabhtty study cfrgnis * 'lomwny 'or...

C*GNISA Company for Biological and Environmental Technology

MlmMota PoRuHon Control AgancyArrowhaad Refinery

2^ UPDATE REPORTCOQNIS Twraftter Uad Extraction

Phaaa II TraatabHtty Study

CfrGNIS— ;L-i 0 2* 'lomwny 'or Sffiiogoi anfl Environmental

Minnesota Pollution Control AgencyArrowhead Refinery

2nd UPDATE REPORTCOGNIS TerraMet™ Lead Extraction

Phase II Treatability Study

COGNIS, Inc. • 2330 Circadian Way • Santa Rosa, CA 95407(707)575-7155 • Fax:(707)575-7833

C*GMS

SOIL REMEDIATION INVESTIGATION

PHASE II TREATABILITY STUDY

ARROWHEAD REFINERY

HERMANTOWN, MINNESOTA

REPORT

Prepared For:

Minnesota Pollution Control Agency520 Lafayette Road

St. Paul, MN 55155

August 31, 1993

William E. Fristad, Ph.D.Project Manager

C*GMS

TABLE OF CONTENTS

STATEMENT OF THE PROBLEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

CONCLUSIONS TO DATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

SCOPE OF WORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

PHASE I TREATABILITY STUDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Physical Characterization of Soil Sample . . . . . . . . . . . . . . . . . . . . 5

Magnetic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Soil Classification Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Lead Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Leaching Feasibility Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Pre-Leaching Lead and TPH Concentration in Soil . . . . . . . . . . . . . 7COGNIS Metal Leaching Process . . . . . . . . . . . . . . . . . . . . . . . . . 8

PHASE II TREATABILITY STUDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Physical Pretreatment of Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Soil Sieving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Attrition Scrubbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Larger Scale Continuous Leaching of Soil . . . . . . . . . . . . . . . . . . . 16Leaching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Post-Treatment Lead Concentration in Soil . . . . . . . . . . . . . . . . . . . 24

Material Balance On Lead And TPH . . . . . . . . . . . . . . . . . . . . . . . . 25Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

EIMCO Bioreactor Slurry with Subsurface S o i l . . . . . . . . . . . . . . . . 27Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Proposed Remediation Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Cleanup Level Attainable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Estimated Treatment Price . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

APPENDIX A Quality Assurance/Quality Control Data

APPENDIX B COGNIS Standard Operating Procedures Referenced

CfrGMS;CGNIS M«UI &draciKxi TraauoiiRy Studies. 2nO Wias* n upoau ftoport Arrown«ad

STATEMENT OF THE PROBLEM

COGNIS, Inc. (COGNIS) is to perform a Phase II Treatability Study on soil contaminatedwith lead from the Arrowhead Refinery site in Hermantown, MM. COGNIS is to determinewhether the proprietary COGNIS metals extraction process is amenable to removing orsignificantly lowering the lead concentration in the soil. The target level for residual leadwas established at the outset of the study to be < 500 ppm. Lead (Pb) is the onlyhazardous heavy metal known to be at the site, although considerable hydrocarbon (TPH)contamination is present and possibly polycyclic aromatic hydrocarbons (PAHs).

The company operated an oil recycling facility from 1945 -1977. Used oil was treatedwith sulfuric acid and filtered to give an acidic filter cake, sludge and oil. Contaminationat the site is known to be in the sludge, filter cake, and surrounding soil which was morelightly contaminated with oil and lead. Lead is a common contaminant of used oil frominternal combustion engines which ran on leaded gasoline.

COGNIS was requested to perform the Phase II Treatability Study for the MinnesotaPollution Control Agency based on a contract with a final signature on February 5,1993.The contract, initiated January 25, 1993, was signed by Dr. Kenneth MacKay, Presidentof COGNIS, Inc. on January 29, 1993. The Arrowhead Refinery site is on the MinnesotaSuperfund Permanent List of Priorities dated December 1991.

CfrGMS:O<3NIS M«tM Extracoon Trvaitttty StudlM. 2na Ptu** ll update Ftopon. ArrownMd

CONCLUSIONS TO DATE

Pretreatment and leaching of the subsurface soil reduced the lead concentration by overtwo thirds to < 200 ppm residual Pb (bench-scale unit, Phase I test) and < 300 ppm(continuous unit, Phase II test). On full-scale remediation, residual lead concentrationsafter complete treatment of < 500 ppm (cleanup standard) would be very achievable.The treated soil passes TCLP for lead (<5 ppm Pb). This is based on return of all treatedsoil to the site.

One additional set of duplicate runs with optimized soil washing conditions is yet to berun. These conditions should give even better lead leaching results. The lower residuallead levels expected should also give lower TCLP values on this optimally treated soil.

The surface soil sample was much higher in lead. Improved soil washing conditionshave led to acceptable lead removal. Currently, ca. 90% of the lead is readily leached,leaving < 1,000 ppm residual lead. Since this surface sample does not represent a largepercentage of the site soil (estimated to be < 5-10% this type of soil), this level ofremediation is considered acceptable.

The proposed processing scheme to date involves grizzly screening of gross oversize,attrition scrubbing of the soil with an oil emulsifying solution to somewhat reduce the TPHcontamination, particle size separation into a clean gravel fraction and contaminated sandand fines fractions, and leaching of the pretreated sand and fines. Particle sizeclassification alone, i.e. "soil washing" with the emulsifying solution, may generate a clean(<500 ppm) sand fraction from the majority, if not all of the sand at the site. If the sandis sufficiently clean, only the fines may need to be leached to remove lead. The treatedoversize, sand and fines are to be redeposited on-srte after treatment. The lead leachedsoil will still contain a substantial amount of the original oil. The recovered oil afterdeemulsification will have to be handled as a separate disposal issue. It should beconsidered for incineration as off-spec oil.

CfcGMSCOGNIS MMM Exlractton TreataCMMy StudWs. 2nd PTUM II UfXM* Report Airwn«aa Raflrwy

SCOPE OF WORK

The scope of the work described in the proposal and included in the contract signed byCOGNIS and the Minnesota Pollution Control Agency is as follows:

Phase II Treatabllity study: Lead RemovalFurther evaluation of the best option (s) identified in Phase IEvaluate feasibility of soil classification prior to lead removalEstablishment of parameters for process recyclabilrtyProcess optimization; physical handling, chemistry, and separationsProcess scale-up; physical treatment, leaching, and lead recoveryVerification of the remediation level to be expectedTCLP testing of the treated soilProvide basic distribution of the soil fractions; oversize, sand, finesSummary report containing all experimental data, estimated treatment cost

($/ton, ±20% confidence level) and time frame for remediation

Phase II Treatabllity Study: Organic Blodegradatlon• Perform "batch" bioslurry degradation of TPH• Document degree of biodegradation to be expected• Study effect of additives to the bioslurry reactor

The final set of Phase II lead leaching under optimized conditions are not yet available.These results will be reported in the Final Report.

CfrGMSCOGNIS MM« Extraction TmattUHy Studto*. 2nd ftMM ll UpdM* Report

PHASE I TREATABILITY STUDY

The original Phase I treatability study was performed on a 5 gallon sample (COGNISidentification IS #67). For the Phase II study additional material was supplied (COGNISidentification TS #204). In order to fully understand the behavior of this latter sample inthe Phase II study, a portion of the Phase I study was repeated on the TS #204 sample.The Phase I data on TS #204 is summarized in this section. The Phase I data on the TS#67 sample has been previously reported.

Physical Characterization of Soil Sample

The second sample (TS #204) was received in three five gallon pails. Two of thesesample buckets were taken from a 2 • 3 foot depth ("subsurface") on the site and the thirdwas taken to a 1 foot depth ("surface"). The surface sample was found to be more highlycontaminated with both organics and lead. The moisture content of the surface soil asreceived was 8% and the subsurface soil was 15%.

Magnetic Properties________________________________

Magnetic separations were not conducted on this soil. No significant amount of ferrousmetal was found in the sample, and the history of the site would not predict unusualamounts of magnetic material.

Soil Classification Potential____________________________

The presence of approximately 30% oversize (>2.00 mm) material in the soil would makethis an ideal candidate for soil washing (particle size classification), i.e. particle sizeseparation and further treatment of onty the fines fraction. Tables I and II summarize thesoil classification data for the surface and subsurface samples. The goal of soil washingwould be to separate the oversize as a clean fraction, free of lead. The sand fraction, aswill be seen later, may be considered dean after washing, or may require leaching inorder to further lower the lead level and to more comfortably pass TCLP for lead. Thefines will definitely require leaching as they hold most of the lead.

COGNIS M«UJ Extraction TrwiaCMlMy StuaM. 2nd RUM ll UpcUt* fltport A/rowTMM ftoflrwyC*GMS

Table I.Soil Classification, Surface Sample

SoilFraction(mesh)

> 4

4-140

<140

Total

SoilWeight

(g)3,264

3,450

2,480

9,194

SoilWeightFraction

(%)35

38

27

100

Table II.Soil Classification, Subsurface Sample

SoilFraction(mesh)

> 44-140

<140Total

SoilWeight

(9)2,695

4,208

2,730

9,633

SoilWeightFraction

{%)28

44

28

100

Lead Source

The most likely sources of lead contamination at this site are various lead salts/oxidesfrom combustion of leaded gasoline found in the used oil and lead sulfate from thesulfunc acid precipitation step in the used oil refining. Over time the lead sulfate mayhave been converted into other lead salts. Metallic lead is not expected to be present atthe site.

CfrGMS:OGNIS Mtnai Exiracuon TrMUDURy Studtas, 2nd RUM 11 uptuw Report. Arrwrwaa Rsflrwry

Leaching Feasibility Analysis

Pre-Leachlng Lead and TPH Concentration in Soil

Soil Washed Surface SampleThe soil washed surface fractions {sand and fines) were recombined and triplicatesamples subjected to EPA acid digestion and lead analysis. The values obtained were9,310 ppm, 10,60X3 ppm and 9,340 ppm, Average = 9,750 ppm total lead. The surfacesample had a much higher lead concentration than the TS #67 sample and thesubsurface sample. Duplicate TPH analysis on soil washed samples contained 3.47% and4.20% by gravimetric analysis and 4.15% and 4.83% by the infrared method.

Soil Washed Subsurface SampleThe soil washed subsurface sand and fines were analyzed separately. The sand fractiongave triplicate lead analyses of 236 ppm, 210 ppm, and 221 ppm, Avg = 222 ppm lead.The fines fraction gave triplicate measurements of 1670 ppm, 1670 ppm, and 1610 ppm,Avg = 1650 ppm total lead. Therefore, the subsurface soil used in the experimentsdescribed in this Report would be calculated to have total lead concentrations as below:

Cone. fpprrri Percentage (%) Contribution (ppm)Fines 1650 40 660Sand 222 60 133

Lead Concentration in sieved subsurface soil 793 ppm (ca. 800 ppm)

Duplicate TPH measurements by the infrared method found 7.8% and 8.0% TPH in thesoil washed fines and 0.90% and 0.96% TPH in the sand fraction.

Subsurface, BloremedlatedLead analyses were not taken before bioremediation of the sample. However, afterblending 1:1 with uncontaminated soil (Goldridge sandy loam) in. order to generateenough sample to load the bioreactor, the soil contained 426 ppm lead (by XRF). Thus,the original soil would have contained 852 ppm lead. TPH analysis prior tobioremediation, but after blending, gave 3.37% TPH (gravimetric analysis), or 6.74% in theoriginal soil. TPH measurement after bioremediation found 0.73% and 0.90% in duplicatesamples. Bioremediation in this sample had degraded almost 90% of the TPH.

CfcGMSCOGNIS M*tai Extraction TrMaDMVy Stuctttt. 2nd PhM* II UpdM ffeport Anowrwaa HMkwry

COGNIS Metal Leaching Process_________________________

Because a new sample was obtained (TS #204) additional Phase I leaching studies wereconducted in addition to the Phase II study. The Phase I results reported here are all onthe TS #204 sample. Phase I leaching results on TS #67 were reported previously.

The COGNIS Phase I bench-scale metal leaching process was conducted on small,duplicate or triplicate samples of the soil in order to determine leaching feasibility. Thisscale allowed the leaching and acid digestion data to be gathered on the exact same soilsample so that no sampling errors were introduced. In this way the amount of Pbleached from the soil plus the residual Pb remaining in the soil can be added together togive the amount of Pb initially in the soil sample and the percentage of teachable Pbcalculated with confidence.

A series of conditions were checked because teachability is a function of the soil type, Pbconcentration, form of Pb contamination, strength of the binding mechanisms, and otherunknown parameters at the outset of the investigation. The effectiveness of any leachantand optimum conditions of its use must be determined empirically.

The results in the following five Tables (III - VII) summarize the leaching results for the soilwashed surface sand plus fines (recombined) sample under five different conditions.Condition #2 employed a longer leaching time than #1 and #3 employed a higherleachant: soil ratio than #1. In these three cases the results are similar, only 40 - 50%of the total lead is leached. The reason for the difficulty in leaching is that the TPH levelin the soil washed surface sample was still high (4 - 5%), and leaching of suchhydrophobic soil was shown to be difficult in the Phase I Report. Lead is being slowly butsteadily leached, and with continued contacts, the lead level would be lowered. However,the TPH level must be further lowered by more efficient soil washing before lead leachingwill be successful.

Condition #4 employed a caustic wash step in the soil washing process in an attempt toincrease the efficiency of the TPH removal. Table VI shows that this wash step followedby standard leaching removes approximately 65% of the lead. Condition #5 differed from#4 in the inclusion of a wash additive to the caustic wash step. Table VII shows that upto 90% removal of lead was accomplished with this pretreatment followed by standardleaching.

The removal of ca. 90% of the lead leaving ca. 1,000 ppm residual lead was deemedacceptable since this surface sample represents a very small percentage of the total soilat the site. The lead contamination in the surface sample also starts at more than 10times (ca. 10,000 ppm vs ca. 800 ppm) the level found in the subsurface, or more normal,soil at the site.

In full-scale operation, this caustic wash could be incorporated into the soil washingintroducing no extra steps to the process.

8

COGNlS M«ai Extraction TmalatMWy SUxUw. 2nd F*UM ll Upon Rtgort. ArrowHMd FWInwyC*GMS

Table 111.Leaching1 of Soil Washed Surface Sand + Fines

Conditions

11

Cumulative % Pb LeachedLeaching Contact #

1

18

19

2

25

26

3

30

31

4

34

35

5

38

38

Initial2

[Pb](ppm)

10,600

10,100

Final3

[Pb](ppm)

6,640

6,280

1 Data Is from five consecutive contacts of soil samples with leachant.2Based upon the total Pb detected in leachant plus Pb retained in soil asdetermined by nitric acid digestion.3Based upon EPA acid digestion of treated soil.

Table IV.Leaching1 of Soil Washed Surface Sand + Fines

Conditions

2

2

2


1

18

21

20

2

27

30

30

3

33

36

35

4

37

41

40

5

41

46

45

Initial2

[Pb}(ppm)

12,300

10,900

10,800

Final3

[Pb](ppm)

7,230

5,840

5,910

'Data is from five consecutive contacts of soil samples with leachant.'Based upon the total Pb detected In leachant plus Pb retained in son asdetermined by nitric acid digestion.'Based upon EPA acid digestion of treated sol

C*GMSCOGNiS MMI Extraction Trttfautty Stud**, 2nd RUM n upom Mpon wwn«aa

Table V.Leaching1 of Soil Washed Surface Sand + Fines

Conditions

33


1

25

25

2

33

31

3

38

36

4

43

40

5

47

43

Initial2

[Pb}(ppm)

9,480

10,700

Final3

[Pb]

(ppm)

5,020

6,150

'Data is from five consecutive contacts of soil samples with teachant.2Based upon the total Pb detected in leacnant plus Pb retained in soil asdetermined by nitric acid digestion.3Based upon EPA acid digestion of treated soil.

Table VI.Leaching1 of Soil Washed Surface Sand + Fines

Conditions

4

4

4


126

2827

2

39

48

41

3

47

56

48

4

51

61

53

5

55

65

57

6

59

68

60

7

62

71

64

initial2

[Pb](ppm)

12,470

11,320

11,700

Final3

[Pb](ppm)

4,750

3,290

4,250

'Data to from seven consecutive contacts of soil samples with leacnant.*Baaed upon the total Pb detected In leacnant plus Pb retained In soil asdetermined by nitric acid digestion.'Based upon EPA add digestion of treated soil.

10

COGNIS hMM Extraction TrMUUHTy StucttM. 2nd RUM il updtf* Rvport *ro*fi«adC*GMS

Table VII.Leaching1 of Soil Washed Surface Sand + Fines

Conditions

5

5

5

Cumulative % Lead LeachedLeaching Contact #

1

45

49

46

2

72

77

72

3

78

85

82

4

81

88

86

5

83

90

89

6

84

92

92

7

85

92

93

Initial*

[PbJ(ppm)

11,040

11,430

14,510

Rnal3

[Pb](ppm)

1,640

861

968

'Datais from seven consecutive contacts of soil samples with leachant2Based upon the total Pb detected in leachant plus Pb retained In soil asdetermined by nitric acid digestion.'Based upon EPA acid digestion of treated soil.

11

C*GMSCOGNIS tMM extraction TrMUUHv StuoiM, 2nd RUM tl UpdM* ftoport MroMttMd Rrtlnwy

The soil washed subsurface sand and fines fractions were separately leached with theresults summarized in the following four tables (Table VII! - XI).

For the subsurface sample the efficiency of oil removal in the standard soil washing stage(classification) was sufficient to remove oil and allow satisfactory lead leaching. As shownin Table VIII, the sand fraction starts below the 500 ppm total lead limit; however leachingremoved an additional 60% of the lead. Approximately 60% of the lead present is alsoleached from the fines fraction, and the lead concentration in the fines fraction afterleaching is in the 650 - 700 ppm range. This is sufficient to give a satisfactory (< 500 ppmtotal lead) concentration in the composite soil when the sand and fines are remixed intheir normal ratio and returned to the site.

As demonstrated with the surface soil, even better results are obtained when a causticwash step with an additive is incorporated before leaching (condition #5, Table IX).Condition #6, Table X involved a shorter more realistic caustic washing time as well asa lower liquid to solid ratio. These conditions better mimic those that would be used inthe full-scale operation. As seen in Table X under these conditions the residual leadlevels are still very good. Conditions #7 and #8 mimic #6 but use different washadditives. Condition #9 was run at 50 °C to see if the addition of heat to the systemwould help free the oil from the fine soil particles. Clearly, the washing/leachingconditions #8 are the optimum conditions for room temperature treatment of the fines.Leaching at elevated temperature is even more effective.

In sum/nan/, the subsurface sand and tines are adequately leached under conditions #8(residual lead in sand is < 100 ppm, Ones is <450ppm) which could be readity seated-up to a full-scale remediation system. While leaching at 50 °C Is clearly superior toleaching at 22 °C (room temperature), the cost of the additional heat input may not bejustified on the full-scale remediation.

12

COGNIS MMM Extraction Traaaewy Stud***, 2nd Phw* ll UpdM* ftaport AmwvHMd R*fln«ryC*GMS

Table VIII.Leaching1 of Soil Washed Subsurface Fractions

Soft/Conditions

Sand/#1Sand/#1

Fines/#1Fines/#1Fines/* 1

Cumulative % Pb LeachedLeeching Contact #

142

38

37

35

35

2

51

48

50

48

49

3

55

53

57

55

56

4

58

55

60

59

59

5

59

57

62

61

61

Initial2

[Pb]

(ppm)

211

201

1,720

1,760

1,750

Final3

[Pb](ppm)

86

86

656

686

674

'Data Is from five consecutive contacts of soil samples with leachant.2Based upon the total Pb detected In leachant plus Pb retained In soil as determined bynitric acid digestion.3Based upon EPA acid digestion of treated soil.

Table IX.Leaching1 of Soil Washed Subsurface Fractions

SoU/Condftioos

Sand/#5

Sand/#5Rnes/#5Rnes/*5


149

57

55

54

2

59

67

70

69

3

62

71

73

72

4

64

73

75

74

5

65

74

76

75

6

67

76

77

76

7

68

78

77

76

Initial2

[Pb}(ppm)

250

199

1592

1633

FinaP[Pb]

(ppm)

80

43.5

359

388

'Datato from seven consecutive contacts of soil samples with leachant2Based upon the total Pb detected In leachant plus Pb retained In soil as determined bynitric add digestion.38ased upon EPA acid digestion of treated soil.

13

COGNlS Extraction TPMUCMWV StudM* 2nd RUM tl UptUM Report. AnowMM RrtnwyC*GMS

Table X.Leaching1 of Soil Washed Subsurface Fractions

Soil/Conditions

Sand/#6Sand/#6

Fines/#6Fines/#6


1

44

40

48

45

2

53

48

61

59

3

57

52

66

64

4

60

55

66

66

5

62

57

67

68

6

64

58

69

69

7

65

60

70

70

Initial2

[Pb](ppm)

221

255

1700

1666

RnaP

[Pb]

(ppm)

77

103

517

501

1 Data is from seven consecutive contacts of soil samples with leachant.28ased upon the total Pb detected in leachant plus Pb retained In soil as determined bynitric acid digestion.'Based upon EPA acid digestion of treated soil.

Table XI.Leaching1 of Soil Washed Subsurface Fines

Condition#7

#7

#8

#8

*9

#9

Cumulative % Pb LeachedLeeching Contact #

1

4545

51

51

52

52

2

56

57

66

66

69

69

3

61

61

70

71

76

75

4

67

67

75

75

79

78

5

68

69

76

76

81

81

6

69

69

76

77

83

82

7

—

—

—

—

83

83

Initial2

[Pb}(ppm)

1750

1706

1779

1749

1811

1780

Final*

[Pb](ppm}

551

531

424

409

311

311

'Data is from six or seven consecutive contacts of soil samples wtth leachant.2Based upon the total Pb detected in leachant plus Pb retained in soil as determined bynitric acid digestion.3Based upon EPA acid digestion of treated soil.

14

CfrGMSCOGNIS Extraction StudM* 2nd Rww u UpdMi ftoport. Rafln*ry

In addition to oil removal by soil washing techniques, bioremediation of the TPH andPAHs at the site was also investigated. The bioremediation results are reported in a latersection. A sample of bioremediated soil was subjected to leaching to verify that removalof substantial hydrocarbon loading would allow lead leaching to be effective. In Table XIIbelow are summarized the leaching results with subsurface soil (recombined sand plusfines). The percentage of lead removal was high (70%), and the final lead concentrationwas also low. This subsurface soil had been blended 1:1 with clean soil, so the resultsreally mean that the subsurface soil was leached from an initial 870 ppm lead to 260 ppmlead, i.e. multiply the lead concentrations in Table XII by two.

Table XII.Leaching1 of Bioremediated Subsurface Sand + Fines

Soil/Conditions

Sand+Fines/#10Sand+Fines/#10


150

49

2

64

62

3

68

66

4

71

68

5

72

69

Initial2

[Pb](ppm)434435

Final3

[Pb]

(Ppm)122134

'Data Is from five consecutive contacts of soil samples with leachant.'Based upon the total Pb detected In leachant plus Pb retained in soil as determined bynitric acid digestion.'Based upon ERA acid digestion of treated sod.

The final post-treatment lead levels after bioremediation and lead leaching were similar tothose after soil washing and lead leaching as shown below, assuming cleanup levels of90 ppm for sand (Table X, Cond. #6) and 420 ppm for fines (Table XI, Cond. #8).

Bioremediation/LeachSoil Wash/Leach 90 ppm (60%) + 420 ppm (40%)

= 260 ppm= 222 ppm

15

;OGNiS Metal Extraction Tr»«att«y stucttOT, 2nd UpcUM taped A/TOWTMMC*»GMS

PHASE II TREATABILITY STUDY

Physical Pretreatment of Soil

Soil Sieving

The soil sieving data on IS #204 was presented earlier. The relative amounts ofoversize, sand and fines has varied with each sample. A summary of the sieving data ispresented below in Table XIII. For calculations in the Cleanup Level Attainable sectionof this Report, the average ratio of oversize : sand : fines being used for the site is 30%: 45% : 25%.

Table XIII.Compilation of Sieving Data

SampleTS #204, Surface

TS #204, Subsurface

TS#67

Oversize352825

Sand3844

64

Rnes27

28

11

Attrition Scrubbing

In order to remove oil from the surface of the soil particles, the soil was vigorouslyagitated with the washing solution. The amount of agitation used can be achieved atfield-scale with a conventional trommel washer. A trommel is currently part of the soilwashing plant. If higher scrubbing intensity is found to be required to adequately removeoil from the surface soil, this would likely be accomplished by a commercial attritionscrubber. Further scrubbing of the surface soil could be investigated in a pilot study.

Larger Scale Continuous Leaching of Soil

Leaching_____________________________________

Larger scale teachings were conducted in order to verify the leaching results on a largerscale as well as identify physical handling problems. The Phase II leaching unit is a smallscale model of full-scale process equipment. It employs an agitated leaching vessel fromwhich a soil slurry is pumped into a darifier. The ctarifier separates the slurry into aclarified feed at the overflow and a thickened slurry at the underflow. The underflow slurryis continuously returned to the leaching vessel. The overflow is pumped into the metal

16

COGNIS M«w Extraction TrMUOMy Studta*. 2nd RUM ll llpdtt* ftoport. AmmffMKi FMrwcy C*GMS

recovery unit where the lead is removed from the leachant and the lead recovered assolid flakes/powder of metallic lead. The barren leachant after lead removal is returnedto the leaching vessel. After leaching is complete, the soil-leachant slurry is dewateredand neutralized. Thus, the entire leaching, clarification and metal recovery processoperates continuously on the batch of soil in the leaching vessel.

The Phase II leaching tests are run for a specified period of time with aliquots taken of thelead-loaded leachate before metal recovery and lead-depleted leachate after metalrecovery to ensure proper functioning of the metal recovery unit and to monitor the leadremoved from the soil. At the end of the leaching cycle, the soil-leachate slurry isneutralized, the soil dewatered and dried. The treated soil is sampled in replicate andanalyzed by EPA acid digestion to determine with reasonable confidence the residual leadconcentration in the remediated soil. A schematic drawing of the process is shown belowin Figure 1.

Continuous Leaching Scheme

regenerated leachant

sediment-leachantslurry

overflowclarified

feedunderflow slurry

RecoveredMetals

Figure 1.

In the first Phase II experiment (Table XIV), the soil washed surface sample was leached.The lead concentration was lowered by 50% to approximately 5,000 ppm. This was aslight improvement over the Phase I results under the same soil washing conditions.Phase I leaching removed on average 45% to ca. 6,000 ppm residual lead. Importantly,it demonstrated that the Phase I results were certainly reproducible at the Phase II level.The overall lead removal in this soil washed surface sample was not adequate, but thiscan be addressed further in the next few weeks.

The influent and effluent samples from metal recovery also indicate that the efficiency oflead recovery is high (a 95%). Therefore, the difficulty in reducing the lead concentrationis a leaching problem and not a result of inefficient metal recovery. This verifies that thestandard metal recovery process should remove lead satisfactorily from this particularleachate, i.e. no site-specific complications with lead recovery were observed.

17

CfrGMSCOGNlS MMM Extraction TrMttttwy StudM*. 2nd PTw* ll Updtf* Report. Anwn««a

Table XIV.Phase II Leaching of Soil Washed (Cond. #1) Surface Whole Soil*

Matrix

Soil (Avg)

Replicate 1Replicate 2

Replicate 3

LeachateSample 1Sample 2Sample 3Sample 4Sample 5Sample 6Sample 7

Lead Concentration ( g/mL orj/g/g)Pre-Leaching

9,750

10,600

9,310

9,340

Influent

6.4—

49.5

37.8

40.2

111°

90.8

Leached5,090

5,580

4,940

4,740

Effluent«

4.6

2.7

2.0

1.8

4.8

10.5

"Soil was neutralized after leaching with calcium carbonate. Recovered soil after drying (98% recovery).^The improvement in leaching at this point was due to improved mixing. Better mixing through the courseof the entire experiment should have given significantly better teaching results.

18

C*GMSCOGNIS M«tat Extraction Tr*ouoiwv StuOM*. 2na II UpOM Rtport. R*fln*rv

The next four runs were conducted on duplicate soil washed subsurface fines (Table XV& XVI) and soil washed subsurface sand (Table XVII & XVIII). The soil washingconditions were identical to the Phase I experiment, Table VIII, Cond. #1 (non-optimized).The results show that the fines can be leached down to 830 ppm residual lead (50%removal), while the sand can be leached down to 100 ppm lead (55% removal). Theseresults meet the cleanup criteria of < 500 ppm residual lead when the lead concentrationin the average soil (oversize, sand and fines) is calculated based on the leadconcentration in each fraction (see Cleanup Level Attainable section of this Report).

Thus, the subsurface soil can be washed and leached to betow the established cleanupcriteria of < 500 ppm residual lead.

In the fines run the metal recovery unit still removed >90% of the dissolved lead from theleachant on one pass through the unit. TOs is considered acceptable. The metalremoval efficiency on the sand run was somewhat less; however, the initial concentrationof lead to be removed is very low. The lead removal efficiency under these conditions isalso considered acceptable.

Table XV.Phase II Leaching of Soli Washed (Cond. #1) Subsurface Fines'

Matrix

Soil (Avg.)

Replicate 1

Replicate 2Replicate 3

LeachateSample 1

Sample2SampledSample 4Sample 5Sample 6

Lead Concentration fyg/mL or jug/g)Pre-Leaching

1,6501,610

. 1,6701,670

Influent51.5

30.2

46.3

26.4

14.8

11.5

Leached

830805

814

872

Effluent4.7

3.5

< 0.5

2.4

1.6

0.9

'Soil was neutralized after leaching with calcium carbonate. Recovered soil after drying (98% recovery).

19

C*GMSCOGNiS MMM Extrecdon TrMttcwy StudM. 2nd RWM II Updrt* Report. Airowfwad Artkwy

Table XVI.Phase II Leaching of Soil Washed (Cond. #1) Subsurface Rnes1 Duplicate

Matrix

Soil (Avg.)

Replicate 1Replicate 2Replicate 3

LeachateSample 1

Sample 2Sample 3Sample 4Sample 5

Lead Concentration (jug/mL orjug/g)Pre-Leaching

1,650

1,610

1,670

1,670

Influent50.138.5

18.9

10.9

7.7

Leached838

831

843

841

Effluent13.5

3.21.1

< 0.5

< 0.5

"Soil was neutralized after teaching wtth calcium carbonate. Recovered sol after drying (96.8% recovery).Table XVII.

Phase II Leaching of Soil Washed (Cond. #1) Subsurface Sand*

Matrix

Soil (Avg.)


LeachateSample 1Sample 2Sample 3Sample 4Sample 5

Lead Concentration (ug/mL or pg/g)Pre-Leaching

222

236

210

221

Influent8.6

—

4.8

4.8

2.6

Leached100

81.4

89.5

129

Effluent—

1.4

2.7

1.5

0.7

'Soil was neutralized after leaching with calcium carbonate. Recovered son after drying (98.3% recovery).

20

CfrGMSCOGNIS M«w Extraction TrvMCMy ShjOM*. 2nd RUM ll Updtf* Report.

Table XVlll.Phase II Leaching of Soil Washed (Cond. #1) Subsurface Sand* Duplicate

Matrix

Soil (Avg.)


LeachateSample 1Sample 2Sample 3Sample 4Sample 5

Sample 6

Lead Concentration (ug/mL or ug/g)Pre-Leaching

222

236

210

221

Influent8.1

—

4.8

1.5

1.3

1.5

Leached94

10187

-

Effluent1.41.2

< 0.7

< 0.7

< 0.7

«

"Soil was neutralized after leaching with calcium carbonate. Recovered soil after drying (99.4% recovery).

77)e Phase II results in Tables XV - XVH/ meet the cleanup criteria; hcwever, the soilwashing conditions (Conditions $1) used correspond to those shown in Phase Iexperiments and are dearly not optimal. Therefore, Phase II experiments will be repealedunder more favorable soil washing conditions, Conditions *& These results will bereported shortly.

21

C*GMSCOGNIS MMat Extraction TrMUMRy StudM. 2nd Run* H Updtf* Report, fWlrwy

Table XIX.Phase II Leaching of Soli Washed (Cond. #8) Subsurface Fines*

Matrix

Soil (Avg.)


LeachateSample 1Sample 2Sample 3Sample 4Sample 5Sample 6

Lead Concentration fcg/mL or g/g)Pre-Leaching

Influent

Leached

Effluent

"Soil was neutralized after leaching with calcium carbonate. Recovered soil after drying (_% recovery).

22

C*GMSCOGNiS MMM Extmcuon TrMUtMMy StudlM, 2nd il UpdW Report *nwn»aa Rcflrwry

Table XX.Phase II Leaching of Soil Washed (Cond. #8) Subsurface Fines'

Matrix

Soil (Avg.)


Leachate

Sample 1Sample 2Sample 3Sample 4

Sample 5Sample 6

Lead Concentration fcg/mL or pg/g)Pre-Leaching

Influent

Leached

Effluent

'Soil was neutralized after leaching with calcium carbonate. Recovered soil after drying (_% recovery).

23

CfrGMSCOGNIS M«UJ Extraction TrMtaoNRy StudMt. 2nd Rial* II UpcMM flvport

Post-Treatment Lead Concentration In Soil

Samples of the treated subsurface sand (from Table XI) and fines (from Table X) weresubmitted for TCLP testing (D & M Laboratories, Petaluma, CA). The results are shownin Table XXI.

Table XXI.TCLP Results (Lead) on Phase II Leached Soil Fractions

SoilSand

Fines

TCLPLimit5.0

5.0

DetectionLimit (mg/L)

0.15

0.15

Results(mg/L)

3.0

5.4

These TCLP results are disconcertingly high, although when the sand and fines arerecombined, the combined soil would pass TCLP (< 5 ppm). Because of these highTCLP results, Phase II teachings under the optimized soil washing conditions will still beconducted.

The above TCLP results are very surprising since they are not consistent with earlierTCLP tests which showed that untreated soil (TS #67) had a TCLP value of 1.84 ppmPb, and after Phase I leaching under three different conditions (reported in Phase IReport) TCLP values of non-detectable, 0.61, and 0.53 ppm Pb had been obtained. Thelarge discrepancy in TCLP results could be due to sample variability; however, thedifference is very large. COGNIS feels the only satisfactory resolution of the TCLPbehavior to expect from treated soil is to repeat the soil washing-lead leaching under theoptimum conditions as planned.

24

CfrGMSCOGNIS M«Uj Extractor TrMUtMWy StudM. 2nd (***• H UptUM Report. AmnwDMU R*fln*ry

Material Balance On Lead And TPH

In order to document the fate of the lead and TPH in the soil after soil washing, a carefulmass balance experiment was conducted. The goal was to account for all the lead andTPH which was initially present in the soil as ending up in either the washed soil, orremoved to one of the soil washing solutions.

Experimental Procedure_______________________________

Oven dried subsurface soil (200 g) from the site (TS # 204) was attrition washed with 145mL of soil washing solution (Cond. #1). Separate 2 gram samples (in duplicate) of thisstarting soil were submitted for Pb and TPH analysis. After attrition scrubbing the soil wasclassified into sand and sitt/clay fractions using a wet LaMotte classification method. Thesoil fractions were then oven dried and weighed before submitting for final analysis of Pband TPH. Both the attrition solution and classification water were submitted for Pb andTPH as well.

Results________________________________________

The mass balance was very good, 99.5% of the starting soil was recovered as either sandor fines. The mass balance on lead was within expected error. Actually, 2.7% more leadwas found in the soil fractions after soil washing than before. The TPH recovered aftersoil washing showed an unaccounted for loss of 12.6% based on the average initial TPHlevel. However, this is within the expected variation of TPH at the site.

Thus, the mass balance experiment showed that less than 2% of the total lead and lessthan 1% of the total petroleum hydrocarbons dissolved or were dispersed in the washingsolution.

25

CfrGMS:OGNIS M*«u Extraction T maturity SludMt. 2nd Phot ll UpdlM fitport, Amnvrwaa Refinery

Table XXII.Material Balance of Subsurface Soil

PROCESS

ScreenAttrition

Classify

SAMPLE

Starting SoilWash WaterClassification

WaterFines

Sand

LEAD

Cone.fr<g/g)666

14.2

ND

1,264

525

Mass(9)200

145

459

41

158

Pbfeg)

133,200

2,059

0

51,824

82,950

TPH

Cone.fcg/g)35,300

7

24

53,400

25,100

Mass(g)200

145

459

41

158

TPHW

7.06 X106

1,015

11,016

2.19 x 106

3.97 x106

TOTAL RECOVERED

LOSS/GAIN (+/-)

% LOSS/GAIN (+/•)

136,833

+ 3,633

+ 2.7%

6.17 x 106

-0.89 X106

-12.6%

26

CfcGMS:OGNiS M#at Extraction TrMUDHRy SludMs. 2nd RUM it updM Report. AJTOWPMO R«nn*ry

EIMCO Bioreactor Slurry with Subsurface Soil

Background_____________________________________

In anticipation of carrying out experiments in continuous operation of the EIMCO SoilSlurry Bioreactor units with a much larger quantity of soil, this "batch" slurry bioreactorexperiment was intended to demonstrate (1) that TPH could be degraded by theindigenous population in the EIMCO reactor; (2) that when the rate of biodegradation ofTPH by the indigenous population had slowed, addition of more microorganisms fromsewage sludge or commercial cultures could help to degrade the remaining TPH, and (3)assuming unlimited time to operate, what was the maximum possible level ofbiodegradation of the TPH? Because the single reactor was operated in a "batch*process that is typically less efficient than a continuous process using two or three linkedEIMCO bioreactors, the time required for biodegradation in a continuous process usingboth indigenous and commercial microorganisms would most likely be less than in thisexperiment. Several problems with sampling the slurry and measuring the slurry volumealso made the accuracy of some of the analysis at the midpoint of the experimentquestionable.

Setup________________________________________

EIMCO recommends that a soil be characterized by screening and determining itsparticular "hydraulic load"; that is the percentage of solids in a slurry that can prevent thecoarser soil fractions from rapidly settling out of the slurry. Rapid settling can quickly"crash" a bioreactor slurry by jamming the airlifts. Our initial survey indicated that at least35% solids would be needed to support the coarse fractions in screened subsurface soil.

The contents of a single five gallon bucket of subsurface soil (T.S. #204) were wetscreened through a 10 mesh screen for loading in the EIMCO reactor. Due to the largeamount of pebbles and cobbles in this sample, less than half the soil could be used in thebioreactor. To load the reactor at a high enough solids (>35%) level it was necessaryto add additional screened "Goldridge Sandy Loam" soil at about a 1:1 final ratio. ThisGoldridge soil typically contains less than 0.5% organics and more fines than thesubsurface soil sample. Although not previously exposed to petroleum hydrocarbons,one must assume that the Goldridge soil could have contributed to the microbialpopulation that grew up on the petroleum contaminants in the slurry. In spite of thedilution by Goldridge soil the final slurry mixture still contained greater than 33,000 mg/Kg(soil dry weight) of TPH (Table XXIII).

The reactor was run at ambient temperatures with an airflow of approximately 20 CubicFeet per Hour (CFH) to the diffusers. "Die diffuser airflow varied somewhat with changesin the airflow to the airiifters. Ca(OH)2 was added periodically to compensate for the acidpH drive and to keep the slurry within a pH range of 6.6 • 7.4. NH4NO3 and K,PO4 were

27

CfrGMSOGNIS M«<ai Extraction TrwiattWy Stuawt. 2nd PhaM II Updtt* Atpofl, Anowrwad Renn*ry

added at the beginning and after two weeks of operations.

Samples were drawn from the three ports at the bottom middle and top of the slurrybioreactor. The three 100 mL samples were combined, then ether extracted andtransferred to freon (COGNIS SOP020, Appendix B). Total Petroleum Hydrocarbons(TPH) were determined gravimetrically by EPA Method 413.1 (COGNIS SOP019, AppendixB). Total Recoverable Petroleum Hydrocarbons (TRPH) were determined from the non-polar fraction by EPA Method 418.1 (COGNIS SOP018, Appendix B). To determine thedry weight of the slurry, 100 mL samples from each of the three ports were separatelydried in an 80 °C oven until no further weight reduction was seen. Microbial enumeration,pH and nutrient determinations were carried out on samples drawn from the middlesampling port.

Results________________________________________

As can be seen in the second column of Table XXIII, the indigenous microbial populationgrew more than ten fold in the first three days of operation, in a continuous slurryoperation, this elevated population level needed to biodegrade the hydrocarbons wouldbe present from the start. In this batch mode the average TPH level had been reducedby more than 35% within seven days of operation (Table XXIII, third column). When theday 14 and day 21 analyses clearly showed that the initial rate of bioremediation haddrastically slowed down, the reactor was dosed at 21 days and 28 days with activatedsewage sludge, and then dosed at 36 days with a commercial microbial culture (MicroPro G, Microbe Masters, Inc.) to see if the more recalcitrant TPHs could be furtherbiodegraded.

Some problems were encountered by the third week with estimating the total volume ofthe slurry due to foaming. It became clear that the 28 and 36 day TPH analysis mostlikely were obtained from a more concentrated slurry (therefore contained more solids)than what was calculated. Most likely the numbers at 28 and 36 days are on the highside. In the last two samples obtained at 42 and 57 days the solids were determined bydrying and weighing the samples, and therefore these values are much more accurate.

In the absence of measurement of the CO2 evolution or O2 consumption, the viablemicrobial population enumeration and the magnitude of the daily change in slurry pH (the"pH drive") were the best indicators of significant biological activity. The pH drive hasespecially been proven to be a useful means of predicting the biodegradation inunbuffered soil slurry shake flasks typically used by COGNIS for Phase I investigations.Please note how the addition of the commercial culture Micro Pro G (Microbe Masters,Inc.) at 36 days seemed to greatly increase the pH drive in the slurry, while the slurry hada much smaller pH drive after the additions of activated sewage sludge. Possibly theMicro Pro G significantly affected the TPH levels and made large amounts of fatty acidsor other organic acid material from the available TPH. Based on the analytical results, thepH drive, and results from soil slurry shake flask experiments (not shown) it appeared thatthe Micro Pro G culture was able to continue to biodegrade TPH when the indigenousculture had faltered. TTie effect of adding Micro Pro G to the initial slurry or after the

28

CfrGMSCOGNIS M«Ul ExlracUon TrMtaDMRy Studies. 2nd Rwse II UpdaM Report. A/rowneaa Refinery

indigenous population had achieved peak growth cannot be predicted from this singlebioreactor experiment.

The EIMCO BL60 slurry bioreactor ran well for the entire two months of operation, withoutmuch evidence of settling of the coarser fractions to the bottom. Although the mechanicalfoam breaker did prevent serious buildup of backpressure from foaming of the slurry,enough pressure occasionally built up to force a small amount of the slurry up the rakedrive shaft into the gearbox. By the end of this extended (2 month) run there was some(1 Kg?) dried mud in the gearbox, but not enough to interfere with operations.

29

CfrGMS;OGNIS MMAI Exlractton TrMUCxHtv StudlM. 2nd Pnas* II UptUM RtQOrt. AfTOwrwaa R*fln«fY

Table XXIN.EIMCO BIOREACTOR DATA

Subsurface* Clean Soil (Goldrtdge)TIME(days)

01245

6

7

8

9

12

14

16

19

21

23

26

28

30

36

42

43

50

54

5557

61

cfu/mL'

0.170.65

1.07

2.23

2.44

2.84

2.81

4.48

6.4

5.65

NO

10.611.1

11.621.4

7

9.556.2

5.8

ND

NO

10.6

NO

9.25ND

ND

AcidpHdrive/day

0(.47)

(.11)

(.19)(.24)

(.02)

(.3)(.37)

(-2)

(-3)(.16)

(.23)

(.23)

(.21)

(.18)

(.17)

(.16)

(.11)

(-3)(.84)

(.78)

(.90)

(.17)

ND

(.18)

+ .01

TPH(ppm)

33,700

22,200

20,200

18,300

21,300®

20,300*10,800

7,800

Notes

Started 3/23/93

Add additional NH.NO3and KP04as nutrients

Foaming started day 18Added 1 L activated sludgeAdded 200 ml Poiyseed supernatant

Added 1 L activated Sludge

Added 1 L MP-G supernatant9,500 ppm IR

6,900 ppm IR

* = 1 X 10*@ = Estimated due to evaporation in reactor (volume decreased, slurry concentration increased, but wasnot measured)Note: GoJdridge soil was added to increase the percentage of fines In the slurry. This facilitated theoperation of the airltfts in keeping the slurry in suspension.

30

CfrGMSCOGNIS Mtui Exiracflon TrMauuiy SluatM. 2nd RUM il uodM Rtport AmnvriMd Rcflrwry

Proposed Remediation Process

Scheme______________________________________

The initial goal of reducing the total residual lead concentration to < 500 ppm has beenachieved. The treated soil appears visibly less contaminated with TPH and has very littlemotor oil odor. Additional work is being done to achieve still lower residual lead levelsand also to further lower the TCLP.

Proposed Remediation Option A combined soil washing-lead leaching process willreduce the total lead concentration to < 500 ppm in the whole soil returned to the site(oversize, sand and fines). The treated soil will also pass TCLP. This appears justifiablebased on the Phase II data to date. TPH removal was not specifically requested in thelead removal process; however, in order to effectively leach lead from the soil, a portionof the TPH may be removed in order to make the soil particle surfaces less hydrophobicand allow wetting by the aqueous leachant.

The proposed remediation process scheme is illustrated in Figure 2 as a block diagram.The percentages shown by each soil fraction represent roughly the weight percent ofeach fraction present at the end of the treatment process which must either be disposedof or returned to the site.

The site would first require that all vegetation be removed, primarily small trees andgrasses. The soil would then be excavated. It is assumed that a portion of the site wouldbe excavated before start of soil treatment and that excavation would continue throughoutthe remediation, providing soil on an as needed basis. The excavated soil is dryscreened to remove gross oversize debris, a reject gross oversize of +4" or +6" issuggested. If dry screening proves impossible, and this is quite possible because of themarshy nature of the site, screening could be performed wet. The reject oversize can bewater sprayed/rinsed to remove adhering fines. The gross oversize fraction is to bedeposited back on-srte. This material has not been tested for lead concentration or TCLPbehavior, but should fall under the debris classification.

The -4" (-6") material passes through a wet trommel containing a caustic solution toemulsify a portion of the oil. The trommel also cleans gravel of fines by rock-on-rockattrition and ejects rinsed oversize (+'/4N) and generates an aqueous slurry of -Vi" soil(sand, silt and clay) and emulsified oil in water. The + Vi" fraction exits the system at thispoint. It is free of fines, and will consist of gravel and wood.

The soil slurry (-%") then undergoes a separation of the sand from the soil fines. Theseparation is done in an upflow classifier which separates panicles based on settling ratesagainst an upflowing column of water. The fines are swept up and out of the classifier

31

CfrGMS:OGNIS Mew Extraction rreaiawiitv StuCW. 2nd Rias« it UpOM fttpon. A/rovm«a R»fln«fY

and are settled in a standard clarifier. The thickened fines are pumped to the finesleaching circuit. The sand settles down and out of the classifier and is subjected to aslight caustic rinse If it is not leached. The sand fraction may be clean enough for returnon-site after dewatering in a sand screw. If necessary, the sands are leached in acounter-current leaching circuit similarly to the fines.

The oil/water separation must be finalized at the pilot plant scale because on the smallscale operations to date the volume of solution is quite small. However, the current planwould be that the oil and water emulsion is broken and separated in a standard oil-waterseparator. The recovered washing solution is reused in the process. The recovered oilfraction is removed for disposal.

The fines are leached in a counter-current system and finally discharged as a thickenedsludge onto a conveyer for neutralization and remixing with sand and oversize. The metalloaded leachant after leaching contact passes through the metal recovery unit for removalof the dissolved lead. The metal recovery unit regenerates the leachant and the leachantis recycled into the process. The recovered lead is in the form of solid, metallic leadflakes/powder and will be sold as a lead product to a secondary lead smelter.

The cleaned oversize, sand, and fines fractions are neutralized in a pug mill after leaching.The neutralized soil is to be returned to the site. The recovered oil will require disposal.

A more detailed process flow for the BESCORP pretreatment steps and COGNISTerraMet* leaching can be supplied if a decision is made to remediate the site or to verifythe current scheme in a demonstration run.

32

lS M*>lal Fxlracllon Irpalahlllty SUifltes. ?ml Phase II Ufxlale Report. Arrowhead Hefkiery

'3 COGNIS-BESCORP Remediation ProcessPercent of Soil Fractions Through Process

Physical Separation Stage — Emulsif ier

r rrntamioaft.cjL _. _ _^j Screen L —— -^JTrommell ————— >- Particle ———— DSoil

Gross("IVPISI7P

-»4"

20%

Chemical Leaching St

Soil Finesfrom Separation Stnq^

Sandfrom Separation Stnq^

f if nerpqt;^! y)^ ' ' '

Oversize+ 1/4

10%

uiassny

Fines

^ De

age

HLeach I jDewaterma 25%Circuit j " Clarifier

H Leach ICircuit I

["lead"I Recovery

^ nirnHor I

~L

K Dewaterma I -_.. ISand Screw [ 45% |

Lmtestone

J

ewater| ——— »- Sandto Leaching urcun

(if necessary)

Clarifier ^ Finesemulsif ier to Leaching Circuit

/Recovered Oil—— ( for Disposal

/Dewatered \^.f N^iitra)i7Pd Soil J

\ ^^QO/ /x^ ^S^J /Q _s*

/^~~ ~~—-XLead Concentrate

^( lorecycler

Figure 2

33

C*GMSCOGNlS M«taf ExiraclKxi TrMiaDHfly StuOMa. 2na Pnaa* n Updai* fltport. Arrowneao flefliwy

Cleanup Level Attainable_____________________________

Phase II results on the subsurface sample show that residual lead in fully treated wholesoil can be < 500 ppm as stated in the original goal. This value should be reproduciblein the field. The data to date has actually been able to achieve a cleanup level of < 300ppm under the conditions tested, which include all the normal processing steps.

The cleanup levels attainable are calculated below based on the observed cleanup inPhase II experiments on sand (100 ppm) and fines (830 ppm) fractions (Tables XVII andXV) and Phase I data (Tables VIII and XI, Cond. #8). The calculation assumes a sitegradation of 30% oversize, 45% sand and 25% fines. The site gradation is a conservativeestimate based on the gradations listed in Table XIII. The lead content of the oversizefraction has not been measured and would be difficult to measure accurately in any case.A worst case assumption has been made that the oversize will still contain the sameamount of lead as the sand fraction. In all likelihood, the oversize lead concentration ismuch lower because of the much lower surface area of the oversize relative to the sand.

Calculation of Final Lead Concentration in Treated Whole Soil

SubsurfacePhase II Oversize Sand Fines TotalData (0.30)(100) + (0.45)(100) + (0.25)(830) = 283 ppm

SubsurfacePhase I Oversize Sand Fines TotalData (0.30)(86) + (0.45)(86) + (0.25)(417) = 169 ppm

Even lower cleanup levels should be attainable when the final results are in from thecurrently scheduled Phase II experiments using the optimized soil washing solution.

34

CfrGMS;OGNiS Meial Extracilon Tr«aia£Mlffy SUxMs. 2nd Www a upcUM fltoon. A/rownesa Refiner/

Estimated Treatment Price____________________________

The estimated treatment cost for the site is $170/ton ± 20%. This price includes loadingof previously excavated soil into the treatment train, complete treatment process, processanalytical, and sale of the recovered lead as a product of the process. The priceassumes the following:

Quantity: 40,00X3 cu. yds. of soil to be treated.Soil gradation: roughly 30% oversize, 45% sand, 25% fines.The two samples obtained are representative of the site, and that the subsurface

sample is most representative.Level "D" Protective Requirements with occasional times in "C".24 hr/day operation at 20 - 50 tons/hr.Mobilization/Demobilization Charges: $200,000

The price estimate does not include initial excavation, regulatory agency requiredanalytical and QA, or health and safety requirements (plan preparation and on-siteimplementation), although these could be performed by COGNIS/BESCORP as well. Ifthese were to be performed by COGNIS/BESCORP, the additional price estimates wouldbe as follows:

Health & Safety Plan Prep.: $50,000Excavation and Backfill: $12/yard

This treatment estimate can best be refined after completion of a demonstration scale runwhich will allow more accurate chemical consumption costs and cycle time. Otherquestions which control cost are permitting requirements, hours of operation and otherpossible restrictions which may be imposed by the MPCA, the RPs, or other localauthorities.

35

CfrGMSCOGNiS M«tai Extraction TreaatMtty StudMs. 2nd PhaM u UPON* n«pon. A^owrwaa R*An«ry

APPENDIX A

Quality Assurance/Quality Control Data

36

CfcGMS:OGNiS M«t» Exiractton rrMtattllty SluatM. 2nd RMM n updtt* Report. Arrowrwad

Table III. QA/QCDATA

T.S. # : 204

SampleNumber

051

052

053

054

055

056

061

062

063

064

065

066

pH

1.04

0.84

0.81

0.81

0.78

Soil

0.99

0.84

0.81

0.80

0.78

Metals: PbLeach

Contact

1

2

3

4

5

Residue

1

2

3

4

5

Soil Residue

AA(ug/g)

404

156

94.2

98.8

66.6

6640

388

136

97.6

85.9

59

6280

Leach Sample Wt.: 2 gramsLeachate

(g)9.27

10.32

10.32

10.28

10.08

9.86

10.34

10.32

10.25

10.29

Leach(ug)

3745

1610

972

1016

671

3826

1406

1007

880

607

Total(ug)

3745

5355

6327

7343

8014

3826

5232

3239

7120

7727

Total(ug/g)

1873

2678

3164

3671

4007

1913

2616

3120

3560

3863

Total(%)

18

25

30

34

38

19

26

31

35

38

QUAUTY CONTROL

Leachates:

SRM

Spike Recovery

101

108%(107, 109)

Spike Duplicate Recovery 105%(104, 106)

(Acceptable Range 96.36 -104.04)

(Acceptable Range 80 -120%)

RPD * 1.62%

(Acceptable Range 80 • 120%)

RPD = 1.78%

Soils:

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

< 26

< 26

234

229

(Detectable Level - 20)

(Detectable Level * 20)

Recovery - 93.6%

Recovery = 91.6%

RPD = 2.10

37

COGNIS Meta) Extraction TrvdaUMy StudtM. 2nd Chat* ll UpdJM R»poaC*»GMS

Tabto IV. QA/QC DATA

T.S. * ; 204

SampleNumber

041

042

043

044

045

046

051

052

053

054

055

056

061

062

063

064

065

066

PH

1.22

1.02

0.96

0.94

0.94

Soil

1.22

1.00

0.95

0.94

0.94

Soil

1.17

0.99

0.96

0.94

0.93

Metafr Fb

LeachContact

1

2

3

4

5

Residue

1

2

3

4

5

Reefdue

1

2

3

4

5

SollReeidue

AA(ug/g)455

209

127

104

99.3

7230

462

185

123

103

112

5840

440

186

111

103

105

5910

Leach Sampto Wt: 2 grams

Leachat*(g)

9.92

10.41

10.36

10.5

10.52

9.92

10.47

10.32

10.43

10.45

9.92

10.92

10.41

10.4

10.44

Leach(ug)

4514

2176

1316

1092

1045

4583

1938

1269

1074

1170

4365

2031

1156

1071

1096

Total(ug)

4514

6689

8005

9097

10142

4583

6521

7790

8864

10035

4365

6396

7551

8623

9719

Total(ug/g)2257

3345

4003

4549

5071

2292

3260

3895

4432

5017

2182

3196

3776

4311

4859

Total(%)

18

27

33

37

41

21

30

36

41

46

20

30

35

40

45

QUALTTY CONTROL

Leachaltt:

045

061

Duplicate

Duplicate

SRM

102

442

101.3

Soil*:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Oup.

103.5

<20

<20

528

521

RPD - 2.38%

RPD - 0.45%


(Acceptable Range 96.36 - 104.04)

(Detectable Level - 20}


Recovery - 105.2%

Recovery » 104.2%

RPD - 0.95%

38

CfcGMSCOGNIS M«w Extraction TrwtaDONy Studta*. 2nO ffias* II UfXUM R*oort. AmmrtMd FWInwy

Tibia V. QA/QC DATA

T.S. # : 204

SampleNumber

051

052

053

054

055

056

021

022

23

024

025

026

PH

0.94

0.91

0.91

0.90

0.90

Soil

Metals: Pb

LeachContact

1

2

3

4

5

Residue

1

2

3

4

5

Soil Residue

AA(ug/g)

119

39.3

23

22.6

20.1

5020

127

40.3

23.7

20.6

16.9

6150

Leach Sample Wt: 2 grams

Leachate(g)

39.5

40.3

40

40.5

39.9

42.7

31.7

40

40.4

40

Leach(ug)

4701

1584

920

915

802

5423

1278

948

832

676

Total(ug)4701

6284

7204

8120

8922

5423

6700

7648

8481

9157

Total(ug/g)2350

3142

3602

4060

4461

2711

3350

3824

4240

4578

Total(%)

25

33

38

43

47

25

31

36

40

43

QUALITY CONTROL

Leachates:

Spike Recovery 107% (Acceptable Range 80 -120%)

RPD = 3.15%

Soils:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

103.5

< 20

< 20

526

521




Recovery = 105.2%

Recovery - 104.2%

RPD = 0.95%

39

Ejdraaioo Stuowr 2nd RUM H UpaaU flwort. Arnxwrwao C*GMS

TabteVf. QA/QCDATA

T.S. # : 204

SampleNumber

012

013

014

015

016

017

018

019

022

023

024

025

026

027

028

029

032

033

034

035

036

037

036

039

pH

1.3

1,05

1.01

0.98

0.96

0.97

0.97

Soil

.

-

-

.

-

.

-

Soil

.

.

-

-

-

-

.

Matate Pb

Acid LaachContact

i

2

3

4

5

6

7

Ratidua

1

2

3

4

5

6

7

Rasidua

1

2

3

4

5

6

7

SoURMUlM

AA(ug/g)

558

322

177

112

89

79.6

81.1

4750

613

394

170

109

77.8

64.6

66.9

3290

547

323

160

106

89.8

7^875.2

4280

Laach Sampt* V*.: 2 grama

Laachata0)

10.61

10.50

10.34

10.48

10.56

10.60

10.31

10.38

10.48

10.27

10.60

10.32

10.42

10.39

10.52

10.50

10.33

10.47

10.41

10.42

10.37

Laach(ug)

5920

3381

1830

1174

940

844

836

6363

4129

1746

1155

803

673

716

5754

3992

1653

1131

935

759

780

Total<ug)

6430

9811

11640

12815

13755

14599

15435

6838

10967

12713

13666

14671

15344

16060

6254

9646

11299

12430

13365

14124

14904

Total(ug/g)

3215

4906

5820

6408

6878

7300

7718

3489

5484

6457

6394

7336

7672

8030

3127

4823

5650

6215

6683

7062

7452

Total(*)

26

39

47

51

55

59

62

28

46

56

61

65

68

71

27

41

48

53

57

60

64

OUAUTY CONTROL

Laacnataa3pika nacovary

Soils: SRM

Blank

Soil Blank

Soil Spika

Soil Splka Oup.

101%

101.0

< 20

< 20

454

464

(Aooaptabla Ranga 80 -120%)

RPO - 0.44%

(Aocaptabta Ranga 96.36 • 104.04)

(Datactabla Uva< - 20)

(Datactabia Lava! - 20)

Racovary • 90.8%

Raoovary » 92.8%

RPO • 2.07

40

C*GMS

COGNIS M»ut Extract**! Tra«MU«y Studta. 2nd RWM ll Update Mport.

TabtoW. QA/OC DATA

T,S. #: 204

SamplaNumb«r

012

013

014

015

016

017

018

019

022

023

024

025

026

027

028

029

pH

1.45

1.10

1.01

1.00

0.98

0.98

0.98

Soil

.

-

-

-

-

-

-

Mrtato: Pb

Acid LaachContact

1

2

3

4

5

6

7

Rasidut

1

2

3

4

5

6

7

Soil RMidut

AA(ug/o)

792

577

142

61.9

38.9

25.3

19.0

1640

824

640

175

72.9

40.9

284

20.7

861

Uach Sarapl* WL: Zgrama

LaachAt*(g)

10.46

10.31

10.49

'10.52

10.29

10.42

10.67

10.67

10.09

10.39

10.47

10.37

10.16

10.52

Laach(ug)

8284

5948

1489

651

380

263

203

8792

6458

1818

763

424

286

218

Total(ug)

9864

15812

17301

17952

18332

13596

18798

11177

17635

19463

20216

20640

20928

21146

Total(ug/g)

4932

7906

8661

8976

9166

9298

9399

5586

8818

9727

10108

10320

10464

10573

Total(%)

45

72

78

81

83

84

85

49

77

85

88

90

92

92

41

C*GMS

COGNIS M«w Extraction TrMtatoMy SludiM, 2nd Phat* u update Report. Anuwrwad

TabteVII. QA/QCDATA

T.S. #: 204

Sampl*Mum bar

032

033

034

035

036

037

038

039

pH

.

-

•

-

.

-

-

MMate Pb

Acid LaachContact

1

2

3

4

5

6

7

Soil Raaidu*

AAWO)

899

737

267

128

82.2

59.9

49.3

968

Laach Sampl* Wt: 2 grama

Laachat*(9)

10.65

10.24

10.51

10.40

10.38

10.30

10.49

Laach(ug)

9574

7546

2806

1331

853

617

517

Total(ug)

13414

20960

23766

25097

25950

26567

27064

Total(ug/g)6707

10480

11883

12549

12975

13284

13542

Total(%)

46

72

82

86

89

92

93

QUAUTY CONTROL

Laachataa:

025

038

Duplicate

Duplicate

SRM

Spikt Racovtry

Soils: SRM

Soils: Blank

Soil Blank

Soil Spik*

Soil Spike Dup.

72.349.6

102.0

104.0%

101.0

< 20

<20

484

464

RPD - 0.82%

RPO - 0.61%

(Aeoaptabla Rang* 96.36 - 104.04)

(Aeoaptabla Rang* 80 -120%)

(Aooaptabi* Rang* 96.36 • 104.04)

(Datactabla Laval - 20)

(Oataetabla Lav»i . 20)

Raoovary « 90.8%

Raeovery - 92.8%

RPO • 2.07%

42

CfrGMSCOGNiS Extraction Tr*aiao«iy SludiM. 2nd mas* II Upd«« fitpoct R*fln«ry

Tabto VIII. QA/QC DATA

T.S. # : 204

SampleNumber

011

012

013

014

015

016

021

022

023

024

025

026

031

032

033

034

035

036

PH

1.14

0.99

0.97

0.94

0.94

SoU

1.13

0.99

0.96

0.93

0.93

Soil

1.13

1.00

0.97

0.94

0.94

Metals: Pb

LeachContact

1

2

3

4

5

Residue

1

2

3

4

5

Residue

1

2

3

4

5

Soil Residue

AA(ufl/0)

133

43.9

21.2

10.3

6.8

656

130

45.8

24.1

11.2

7.7

686

129

48.4

23.7

11.6

7.2

674

Leach Sample Wt.: 2 grams

Leachate(g)

9.47

10.56

10.51

10.50

10.54

9.42

10.44

10.45

10.40

10.41

9.35

10.2

10.39

10.39

10.41

Leach(ug)

1260

464

223

108

72

1225

478

252

116

80

1206

494

246

121

75

Total(ug)

1260

1723

1946

2054

2126

1225

1703

1955

2071

2151

1206

1700

1946

2067

2142

Total(ug/g)

630

862

973

1027

1063

612

851

977

1036

1076

603

850

973

1033

1071

Total(%)

37

50

57

60

62

35

48

55

59

61

35

49

56

59

61

43

CfcGMSCOGMIS MM* Exlmcdon ShjdtM, 2nd RUM II UpdM ftoport.

TabteVIII. QA/QCDATA

T.S. # : 204

SampleNumber

a HHal051

052

053

054

055

056

061

062

063

064

065

066

PH

^^m1.00

0.95

0.94

0.92

0.92

SOU

-

-

-

-

-

Metals: PbLeach

Contact•ala M

12

3

4

5

Residue

1

2

3

4

5

Soil Residue

AA(ug/Q)

a^aVM18

3.6

1.7

0.9

< 0.7

85.5

15.9

4.2

1.8

1.0

0.7

66

Leach Sample Wt: 2 gramsLeachate

(g)a^a^Hal

9.9

10.4

10.46

10.24

10.55

9.7

9.1

10.53

10.34

10.44

Leach(ug)

••••178

37

18

9

7

154

38

19

10

7

Total(ug)

mmmm178

216

233

243

250

154

192

211

222

229

Total(ug/g)aMHaV

89

108

117

121

125

77

96

106

111

115

Total(%)

•alBH42

51

55

58

59

38

48

53

55

57

QUALITY CONTROL

Leachates:

Spike Recovery 101%

Spike Duplicate Recovery 98.5%

(Acceptable Range 80 - 120%)

RPD - 1.48%


RPD - 2.62%

Soils:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

103.5

< 20

<20

526

521

(Acceptable flange 96.36 - 104.04)



Recovery = 105.2%

Recovery = 104.2%

RPD = 0.95%

44

CfrGMS

COGNIS MMal Extraction TrMUOWty 9udto>. 2nd RUM H Updrt* Rtport,

TabtolX. QA/QCDATA

T.S. # : 204

SampleNumber

012

013

014

015

016

017

018

019

022

023

024

025

026

027

028

029

032

033

034

035

036

037

038

039

PH

1.7

1.13

1.04

1.02

1.00

0.98

1.01

SOD1.65

1.12

1.04

1.01

0.98

0.99

0.97

SOU

1.15

1.01

0.99

0.99

0.96

0.97

0.96

Metals: PbAcid Leach

Contact

1

2

3

4

5

6

7

Residue

1

2

3

4

5

6

7

Residue

1

2

3

4

5

6

7

SoN Residue

AA(ug/g)

167

46.1

10.6

5.1

3.0

2.5

1.8

359

170

45.9

10.8

5.7

3.2

2.4

1.9

388

21.4

4.5

2

0.8

<0.7

<0.7

<0.7

80

Leach Sample Wl: 2 grams

Leachate ,(g)

10.23

10.27

10.26

10.32

10.26

10.33

10.32

10.08

10.45

10.26

10.35

10.28

10.17

10.37

10.30

10.33

10.29

10.33

10.14

10.28

10.50

Leach(ug)

1708

473

109

53

31

26

18.6

1713

479

111

60

33

24

20

220.4

46.5

20.6

8.3

7.1

7.2

7.4

Total(ug)

1757

2231

2339

2391

2422

2449

2467

1762

2242

2352

2413

2446

2470

2490

242.9

289.4

310

318.3

325.4

332.6

340

Total(ug/g)

879

1115

1170

1196

1211

1224

1234

881

1121

1177

1207

1223

1235

1245

121.5

144.7

155

159.2

162.7

166.3

170

Total(%)

55

70

73

75

76

77

77

54

69

72

74

75

76

76

49

59

62

64

65

67

68

45

COGNIS Mew Extraction Tn*ici«y StudkM. 2nd RMM II Updtf* Report. Arrowrwwi Mflnwy

CfrGMS

Tab* IX QA/QCDATA

T.S. # : 204

SampleNumber

042

043

044

045

046

047

048

049

pH

1.16

1.00

0.98

0.96

0.98

0.96

0.96

Metals: PbAcid Leach

Contact

1

2

3

4

5

6

7

Sou Residue

AA(ug/g)19.9

3.8

1.5

0.7

0.7

<0.7

<0.7

43.5

Leach Sample Wt: 2 grams

Leachate(9)

10.15

10.44

10.17

10.49

10.36

10.20

10.36

Leach(ug)

202

39.7

15.3

7.32

7.3

7.1

7.3

Total(ug)

226.2

265.9

281.2

288.5

295.8

302.9

310.2

Total(ug/g)

113.1

133

140.6

144.3

147.9

151.5

155.1

Total(%)57

67

71

73

74

76

78

QUALITY CONTROL

Leachates:

Spike Recovery 111%

Duplicate Spike Recovery 110%


RPD = 0%


RPD - 4.46%

Soils:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

98.6

< 20

< 20

475

487


(Detectable Level = 20)


Recovery = 95%

Recovery = 97.4%

RPD - 2.49%

46

COGNIS MM Erfracikxi TrMUUtty StudlM. 2nd Phtt* II UpdlM Rtport. ArrownMd FMtrwry

C*GMS

TabtoX. QA/QCDATA

T.S. * : 204

SampleNumber

032

033

034

035

036

037

038

039

042

043

044

045

046

047

046

049

012

013

014

015

016

017

016

019

PH

-

-

-

-

-

-

-

Soil

-

-

-

-

-

-

-

SON

-------

Metals: Pb

Acid LeachContact

1

2

3

4

5

6

7

Residue

1

2

3

4

5

6

7

Residue

1

2

3

4

5

6

7

Sol Residue

AA(ug/g)

149

43.8

15.7

8.9

5.2

3.9

3.4

517

140

42.6

15.3

8.4

5.0

3.8

3.3

501

18.7

3.9

1.8

1.2

1.0

0.7

0.6

76.9

teach Sampto Wt.: 2 grams

Leachate(g)

9.85

10.42

10.34

10.26

10.39

10.36

10.40

9.80

10.43

10.42

10.37

10.41

10.39

10.37

10.36

10.35

10.2

10.32

10.31

10.44

10.48

Leach(ug)

1468

456

162

91.3

54.03

40.4

35.36

1372

444.3

159.4

87.1

52.1

39.5

34.2

193.8

40.4

18.36

12.4

10.3

7.3

6.3

Total(ug)

1618

2074

2236

2328

2382

2422

2458

1514

1958

2117.4

2204.5

2256.6

2296.1

2330.3

193.7

234.1

252.5

264.8

275.2

282.5

288.8

Total(ug/g)

809

1037

1118

1164

1191

1211

1229

757

979

1058.7

1102.3

1128.3

1148

1165

96.8

117.1

126.3

132.4

137.6

141.2

144.4

Total(%)

46

59

64

67

68

69

70

45

59

64

66

68

69

70

44

53

57

60

62

64

65

47

CfcGMSCOGNIS Extraction TrMUDWy SludtM, 2nd RWM ii UpdM Report, ArrowhMd FWtn*ry

Tabto X. QA/QC DATA

T.S. * : 204

SampleNumber

022

023

024

025

026

027

022

029

PH

-

-

-

-

-

-

-

Metals: Pb

Acid LeachContact

1

2

3

4

5

6

7

SoU Residue

AA(ug/g)19.9

3.9

1.9

1.3

1.0

0.8

0.7

103


Leachate(9)

10.32

10.26

10.33

10.24

10.33

10.38

10.46

Leach Total(ug) (ug)

205.4 245.4

40.0 265.0

19.6 278.3

13.3 288.7

10.3 297

8.3 304.3

7.3

Total Total(ug/g) (%)102.7 40

122.7 48

132.5 52

139.2 55

144.3 57

148.5 58

152.1 60

QUALITY CONTROL

Leachatas:

012

022

034

043

Duplicate

Duplicate

Duplicate

Duplicate

SRM

Spike Recovery

18.3

19.9

15.6

42.1

102.6

82.8%

RPD = 1.89%

RPD = 0.00%

RPD - 0.64%

RPD - 1.18%

(Acceptable Range 96.36 -104.04)(Acceptable Range 80 -120%)

Soils:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

< 26

< 26

476

496




Recovery - 95.2%

Recovery * 99.2%

RPD = 4.22

48

CfrGMSCOGNIS MMM Exiracuon Studtot. 2nd RUM II UpdcU fltport, AmwttMd

Table XI. QA/QCDATA

T.S. # : 204

SampleNumber

PH

Metals: Pb

Acid LeachContact

AA(ug/g)


Leachate(g)

Leach(ug)

Total(ug)

Total(ug/g)

Total(%)

Condition #7

031 (7)

032 (7)

033 (7)

034 (7)

035 (7)

036 (7)

037 (7)

038 (7)

041 (7)

042 (7)

043 (7)

044(7)

045 (7)

046(7)

047 (7)

048 (7) }

-

-

-

-

-

-

-

Soil

.

-

-

-

-

-

-

1

2

3

4

5

6

7

Residue

1

2

3

4

5

6

7

Soil Residue

29.8

125

26.6

15.7

20.1

5.6

3.3

551

30.0

123

36.7

14.7

19.4

5.3

3.10

531

8.94

10.39

10.25

10.33

10.16

10.36

10.33

9.04

10.29

10.32

10.29

10.14

10.37

10.30

266.4

1298.8

375.2

162.2

204.2

58.0

34.1

271.2

1265.7

378.7

151.3

196.7

55

31.9

266.4

1565.2

19403

2102.5

2306.7

2364.7

2399

271.2

1536.9

1915.6

2066.9

2263.6

2318.6

2350.5

133.2

782.6

970.2

1051.3

1153.4

1182.4

1199.4

135.6

768.4

957.8

1033.4

1131.8

1159.3

1175.2

8

45

56

61

67

68

69

8

45

57

61

67

69

69

Condition #8

012 (8)

013(8)

014 (8)

015(8)

016 (8)

017 (8)

018 (8)

-

-

-

-

-

-

1

2

3

4

5

6

Sou Residue

177

54.5

15.9

15.7

3.9

2.0

424

10.05

10.25

10.27

10.18

10.27

10.38

1778.9

527.9

163.3

159.8

40.1

20.8

1798.2

2326.1

2489.4

2649.2

2689.2

2710

899.1

1163.0

1244.7

1324.6

1344.6

1355

51

66

70

75

76

76

49

COGNIS MMM Extracdon TPMttOHty Stuotot, 2nd RUM II Updtf* Report. ArrowrwM

C*GMS

TabtoXI. QA/QCDATA

T.S. # : 204

SampleNumber

022 (8)

023 (8)

024 (8)

025 (8)

026 (8)

027 (8)

028 (8)

011 (9)

012 (9)

013 (9)

014 (9)

015 (9)

016 (9)

017(9)

018 (9)

021 (9)

022 (9)

023 (9)

024 (9)

025 (9)

026 (9)

027 (9)

028 (9)

PH

-

-

-

-

-

-

Soil

-

-

-

-

-

-

-

Metals: Pb

Acid LeachContact

1

2

3

4

5

6

Residue

1

2

3

4

5

6

7

Residual Soil

.

-

-

-

-

-

-

1

2

3

4

5

6

7

Restdual Soil

AA(ug/g)

177

51.2

15.7

15.7

3.9

2.0

409

255

61.2

21.4

10.9

8.1

5.3

4.2

311

241

56.6

18.2

10.6

8.3

5.7

3.9

311


Leachate(g)

9.94

10.24

10.41

10.21

10.20

10.31

7.24

10.35

10.34

10.34

10.27

10.67

11.08

7.56

10.82

10.8

10.64

10.89

10.98

10.66

Leachtug)

1759.4

524.3

163.4

160.3

39.8

20.6

1846

633

221

113

83

57

47

1822

612

197

113

90

63

42

Total<ug)

1772.4

2296.7

2460.1

2620.4

2660.2

2680.8

1846

2480

2701

2814

2897

2953

3000

1822

2434

2631

2744

2834

2897

2938

Total(ug/g)

886.2

1148.3

1230

1310.2

1330.1

1340.4

923

1240

1350

1407

1448

1477

1500

911

1217

1315

1372

1417

1448

1469

Total(%)

51

66

71

75

76

77

52

69

76

79

81

83

83

52

69

75

78

81

82

83

50

CfrGMS

COGNIS Extraction TrMUOWty StudM. 2nd RUM II UpdM Report. A/rawftMd

T.S. * : 204

SampleNumber

Leachates:

034(7)

042 (7)

023 (8)

014(9)

022 (9)

SRM (8)

TabtoXl. QA/QCDATA

Metals: PbpH Acid Leach

ContactAA

(ug/g)

Leach Sample Wtr 2 grams

Leachate Leach Total Total Total(9) (ug) (ug) (ug/g) (%)

QUALITY CONTROL

Duplicate

Duplicate

Duplicate

Duplicate

Duplicate

Spike Recovery (8)

Spike Recovery (9)

15.3

123

50.6

10.9

58.2

103

88.9%

90.9%

RPD - 0.33%

RPD = 0.16%

RPD = 1.18%

RPD = 0.46%

RPD = 2.76%




Soils:

SRM (7) (8)

Blank (7) (8)

Blank (9)

Soil Blank (7) (8)

Soil Blank (9)

Soil Spike (7) (8)

Soil Spike Oup. (7) (8)

101.2

< 20

< 26

< 20

< 26

514

519

Soil Spike (9)

Soil Spike Dup (9)

478

468





(Detectable Level = 20)Recovery = 102.8%

Recovery - 103.8%

RPD - 1.9%

Recovery = 95.6%

Recovery = 93.6%

RPD - 2.03%

51

CfrGMS

COGNIS M*W ExlracOor TrMMHMy StuOtM. 2nd RUM II UptMM ftoport. Rtfkwy

T.S. # : 204

SampleNumber

071

072

073

074

075

076

081

082

083

084

085

086

PH

1.14

0.98

0.97

0.94

0.94

Soil

-

-

-

-

-

Tabl« XII. QA/QC DATA

Metals: Pb

LeachContact

1

2

3

4

5

Residue

1

2

3

4

5

Soil Residue

AA(ug/g)46.6

11.5

4

1.7

1.1

122

45.6

11

3.6

1.6

1.0

134


Leachate(g)

9.31

10.37

10.28

10.52

10.39

9.26

10.45

10.25

10.65

10.17

Leach(ug)

434

119

41

18

11

422

115

37

17

10

Total(ug)

434

553

594

612

624

422

537

574

591

601

Total(ug/g)

217

277

297

306

312

211

269

287

296

301

Total(%)

50

64

68

71

72

49

62

66

68

69

QUAUTY CONTROL

Leachates:

Spike Recovery 101% (Acceptable Range 80 -120%)

RPD = 1.48%

Soils:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

103.5

< 20

< 20

526

521




Recovery = 105.2%

Recovery = 104.2%

RPD - 0.95%

52

C*GMS

COGNIS M«W Extmcflon TrNtabMy Studtac. 2nd PhM* H Updttt Rtport AmnwrtMd Mttwy

TabteXIV. QA/QCDATA

QUALITY CONTROL

Leachates:SRM

Spike Recovery

101

108%(108, 109)

Spike Duplicate Recovery 105%(104, 106)



RPO = 1.62%


RPD = 1.78%

Soils:

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

< 26

< 26

234

229



Recovery = 93.6%

Recovery = 91.6%

RPD = 2.10%

53

CfcGMSCOGNIS hMM extraction TrMttDWy Sludln. 2nd PhBM II UpdM Report. ArrownMd fltflrwry

Tabto XV. QA/QC DATA

QUAUTY CONTROL

Leachatet:

Duplicate [3 Influent]


Spike Recovery

46.6

11.5

97.6%

RPD = 0.64%

RPD - 0.00%


Soils:

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

< 26

< 26

473

475

(Detectable Level =

(Detectable Level =

20)

20)

Recovery = 92.4%

Recovery = 92.8%

RPD * 3.09%

54

C*GMSCOGNIS M«d Extraction TrMtaUMy SIUOM. 2nd RWM 11 upon ftoport. A/rowtwea

TabteXVl. QA/QCDATA

QUAUTY CONTROL

Leacnater


SRM

Spike Recovery

19.1 RPD = 1.31%

101.7 (Acceptable Range

93.9% (Acceptable Range

96.36 • 104.04)

80-120%)

Soils:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

101.0 (Acceptable Range

< 20 (Detectable Level -

< 20 (Detectable Level =

96.36 - 104.04)

20)

20)

454 Recovery = 90.8%

464 Recovery = 92.8%

RPD = 2.07%

55

Ct>GMS

COGNIS MMal Extraction TrwiabWy StudlM, 2nd Ria»t II Update Report Arrowrwad Heflnwy

Table XVII. QA/QC DATA

QUAUTY CONTROL

Leachatet:

Duplicate [influent 1 ]

Spike Recovery

8.6

90.9%

RPD = 0.0%


Soil*:

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

< 26

< 26

473

475



Recovery = 92.4%

Recovery - 92.8%

RPD = 3.09%

56

CfcGMS

COGNiS M«UI Extraction TruiaotMty stud**, 2nd RUM n Updau ftoport AmwrtMd Rvfinwy

Tabta XVIII. QA/QC DATA

QUAUTY CONTROL

Leachater

Duplicate (6 Influent]

SRM

Spike Recovery

Spike Duplicate Recovery

1.5

97.3

101%

102%

RPD = 13.13%




Soils:

SRM

Blank

Soil Blank

Soil Spike

Soil Spike Dup.

101.0

< 20

< 20

454

464



(Detectable Level * 20)

Recovery - 90.8%

Recovery = 92.8%

RPD - 2.07%

57

C*GMSCOGNIS hWal Extraction TrMUOHty SudlM, 2nd Rmt II UpdM Ftopon ArrawrtMd

APPENDIX B

COGNIS Standard Operating Procedures Referenced

58

C*GNIS

COGNIS, INC.ANALYTICAL TECHNOLOGY

Page 1 of 4SOP01 8.001

STANDARD OPERATING PROCEDURES

EFFECTIVE: 12-04-92

SUPERSEDES: NONE

TITLE: TOTAL PETROLEUM HYDROCARBONS BY FTIR

APPROVAL: fa^ /?2<*/4^ DATE;

APPROVAL: L T). **7£j£z/. tfd rtL^ DATE: V - /———— ' ™

1.0 PURPOSE AND SCOPE

1.1 This Standard Operating Procedure (SOP) describes a method for themeasurement of extractabte matter from soil and shake flasks, it is applicable tothe determination of hydrocarbons, vegetable oils, animal fats, waxes, soaps,greases and related matter. The method is also applicable to the measurementof most light petroleum fuels, although some loss of any gasoline present duringthe extraction manipulations can be expected.

1.2 The scope of this method includes organic components having a concentration inthe soil of >100 mg/Kg (estimated).

2.0 SUMMARY OF METHOD

2.1 The sample is extracted using the procedure for Shake Flasks SOP020, orUltrasonic Extraction SOP016. TTie extract is diluted and subjected to silica geltreatment before infrared analysis. The petroleum hydrocarbons are determinedby comparison of the infrared absorbance of the sample extract with standards.

3.0 SAFETY HIGHLIGHTS

3.1 ETHYL ETHER (ether) is an extremely flammable liquid, highly volatile, harmful ifswallowed or inhaled, use with adequate ventilation.

3.2 FREON 113 is harmful if inhaled, has anesthetic properties, may cause irritation.

C*GMS

SOP NUMBER SOP018.001 Page 2 of 4

4.0 APPARATUS

4.1 Infrared spectrophotometer, Digitab FTS-60 or equivalent.

4.2 10 mm quartz cell.

4.3 Volumetric flasks, 100, 50, and 25 ml.

4.4 Pipets, 1, 2, 5, 10 ml.

4.5 Sample filter, Prep-Disc BIO-RAD 343-0001 or equivalent.

5.0 REAGENTS

5.1 Freon 113 (l.i^-trichloro-i^-trifluoroethane), pesticide quality or equivalent.

5.2 Sodium sulfate, anhydrous crystals.

5.3 Silica gel, 70-230 mesh, Aldrich catalog # 28,862-4.

5.4 Calibration mixtures:a. Reference oil: Pipet 15.0 ml n-hexadecane, 15.0 ml isooctane, and 10.0 ml

chtorobenzene into a 50 ml glass stoppered bottle.

b. Stock standard: Pipet 1.0 ml reference oil into a tared 200 ml volumetricflask and immediately stopper. Weigh and dilute to volume with freon-113/

c. Working standards: Pipet 1, 2, 4, 5, and 10 ml volumes of stock standardinto 100 ml volumetric flasks to make working standards for the calibrationcurve.

6.0 PROCEDURE

6.1 Pipet 1.0 ml of the extract solution from either the Ultrasonic extraction procedure(COGNIS AT SOP016) or the Shake Flask extraction proceaure (COGNIS ATSOP020) into a 25 ml volumetric flask. Dilute to the mark with freon 113.

6.2 Discard 3-4 ml solution from the volumetric flask. Add 3 g silica gel, stopper andshake for a few seconds every minute for 5 minutes. It is not necessary to addsilica gel to the working standards.

C*GNIS


6.3 Calibrate the instrument using the 10 mm cell and the working standards.Determine the absordance at the peak near 2930 cm"1 for each solution. Preparea calibration plot of absorbance vs. mg petroleum hydrocarbon 100 ml solution.This 5 point calibration must be done on a monthly basis.

6.4 After the silica gel has settled in the sample extract, fill a clean cell with solutionand determine the absorbance of the extract. If the absorbance exceeds 0.8prepare an appropriate dilution. The possibility of the absorptive capacity of thesilica gel has been exceeded can be tested at this point by adding another 3 gsilica gel to the extract and repeating the treatment and determination.

6.5 Calculations:

a. Calculate the petroleum hydrocarbons in the sample using the formula:

mg/kg Petroleum Hydrocarbon - R X D X 1000S

where:

R = mg of petroleum hydrocarbons as determined from thecalibration plot.D = extract dilution factor, if used.S = weight of sample in grams.

6.6 Precision and Accuracy:a. Precision data is not available at this time. Duplicates and triplicates have

been used as part of the pnase 1 measurements, Accuracy measurementsusing spiked soil samples are underway.

7.0 METHOD QC

7.1 For each analytical batch (1-7 samples):

a. Blank. To check method for contamination.

b. Duplicate. To check precision (relative percent difference).

c. Spike. To check accuracy (percent recovery)

d. Laboratory control sample. A secondary standard to check for methodcontrol.

C*GMS

SOP NUMBER SOP018.001 pagt 4 0( 4

3.0 REFERENCES

8.1 Petroleum Hydrocarbon, Total Recoverable. Method 418.1 Storet No. 45501.

8.2 Procedure for glassware cleaning is found in "Chemical Technicians ReadyReference Handbook" (COGNISt Inc. library reference number HTC QD 61.S58).

8.3 Procedure for operation of an analytical balance is found in COGNIS, Inc.Analytical Technology standard operating procedure COGAT-4A and in operatingmanuals of individual balances.

CfrGMS

COGNIS, INC.ANALYTICAL TECHNOLOGY

Page 1 of 3SOP01 9.001


EFFECTIVE: 12-04-92

SUPERSEDES: NONE

TITLE: TOTAL EXTBACTABLES. GRAVIMETRIC METHOD

APPROVAL: -»~ _______ DATE: A -*~f 2~

APPROVAL: >- *ZZ ^A aJ" DATE: /2 - ? '^


1.1 This Standard Operating Procedure (SOP) describes a method that includes themeasurement of extractadle matter from soil samples. It is applicable to thedetermination of hydrocarbons, vegetable oils, animal fats, waxes, soaps, greases,and related matter. The method is applicable to measurement of most lightpetroleum fuels, although some loss of any gasoline present during the extractionmanipulation can be expected.

1.2 Applicable to organic components having a concentration in the soil of >100mg/kg (ppm).


2.1 The sample is extracted using the procedure for Shake Flasks (SOP020) orUltrasonic Extraction (SOP016). An aliquot of the extract is weighed and theamount of total extractables is calculated.


3.1 Ethyl Ether (ether) is an extremely flammable liquid, highly volatile, harmful ifswallowed or inhaled, use with adequate ventilation.

3.2 Freon 113 is harmful if inhaled, has anesthetic properties, and may cause irritation.

C*GMS


4.0 APPARATUS

4.1 Balance, capable of accurately weighing to the nearest 0.1 mg.

4.2 Pipet, 15 ml.

4.3 6 dram glass vials.

5.0 PROCEDURE

5.1 Pipet 15 mi of the extract solution from either the ultrasonic extraction procedure(SOP016) or the Shake Flask extraction procedure (SOP020) into a tared 6 dramglass vial.

5.2 Pipet 15 ml of the extraction solvent into another tared 6 dram vial.

5.3 Remove the solvent on a steam bath under a stream of clean, dry nitrogen.

5.4 Cool down vials to room temperature in a desiccator.

5.5 Determine weight of residue to the nearest 0.1 mg.

6.0 CALCULATIONS

6.1 Calculate the total extractabtes using the following formula:

mg/kg total extractables = (R - m x 3.3333 x 1000W

where:R » weight of residue in mg.8 - weight of blank in mg.3.3333 » 15 of 50 ml used in determination.1000 = g/kg.W = weight of sample in g

C*GNIS


7.0 METHOD QC

7.1 For each analytical batch (1-7 samples):

a. One blank. To check method for contamination.

b. One duplicate. To check precision (relative percent difference).

c. One spike. To check accuracy (percent recovery).

d. One laboratory control samcle. A secondary standard to check for methodcontrol (control chart).

8.0 REFERENCES

8.1 Oil and Grease, Total Recoverable. Method 413.1 Storet No. 00556.

8.2 Procedures for glassware cleaning and use of pipet are described in "ChemicalTechnicians' Ready Reference Handbook" (COGNIS, Inc. library reference numberHTCQD61.S58).


CfrGMS

COGNIS. INC.ANALYTICAL TECHNOLOGY

Page 1 of 4SOP020.001


EFFECTIVE: 12-04-92

SUPERSEDES: NONE

TITLE: SHAKE FM*SK EXTRACTION PROCEDURE

APPROVAL ik6^'/fy£w*~*_______ DATE: / 2. "^ ~^

APPROVAL: /. 2). fZZl. OA aJ^^ DATE: /j? - /-— "


1.1 This Standard Operating Procedure (SOP) describes a method for extractingnonvolatile and semi-volatile organic compounds from shake flasks generallycontaining approximately 30% water and 20 % soil with a total volume ofapproximately 100 ml.

1.2 This method is applicable to organic components having a concentration in the soilof >100 mg/Kg.


2.1 The entire contents of the shake flask is extracted with ethyl ether at least threetimes. The extract is separated from the sample by decanting after centrifugation.The extract is ready for cleanup and/or analysis following concentration. Forinfrared analysis following extraction, a solvent exchange must be performed.


3.1 ETHYL ETHER (ether) is an extremely flammable liquid, highly volatile, harmful ifswallowed or inhaled, and should be used with adequate ventilation.

C*GMS

SOP NUMBER SOP020.001 Page 2 ol 4

4.0 APPARATUS

4.1 250 ml Naigene centrifuge bottles.

4.2 Sorvall Instruments RC5C centrifuge or equivalent.

4.3 Disposable Serological pipets.

4.4 Portable pipet aid filler and dispenser.

4.5 Heated water bath with concentric rings.

4.6 Beakers - 400 ml.

4.7 Boiling chips • silicon carbide.

4.8 Volumetric flasks, 50 ml.

4.9 Millipore pressure filter with 0.5 micron filter membranes.

5.0 REAGENTS

5.1 Sodium sulfate, anhydrous crystals.

5.2 Ethyl Ether, Pesticide quality or equivalent.

5.3 Hydrochloric acid, reagent grade, diluted 1:3 in water.

5.4 Goldridge reference soil.

5.5 Matrix spiking standard mixture (1:1 by weight mixture of Mazola corn oil and n-Hexadecane.

6.0 PROCEDURE

6.1 Sample handling At time of submission all samples are placed in a refrigeratoroperating at approximately 4 °C. and stored until analysis.

C*GMS

SOP NUMBER SOP020.001 Pagt 3 of 4

6.2 Extraction procedure

a. Transfer contents of shake flask into a 250 ml centrifuge bottle. Rinse theshake flask first wrth three 5 ml portions of water followed by three 5 mlportions of ether. Add 3 ml hydrochloric acid solution.

b. To prepare matrix spike; weigh accurately approximately 20 g Gofdridgereference soil into a centrifuge bottle, add 150 mg spiking standard mixture.Record weights to nearest 0.1 mg. Add 80 ml water and approximately 40ml ether and close the bottle.

c. Shake vigorously for two minutes. Release pressure slowly. Recap bottleand centrifuge at 10,000 RPM for 5 minutes to break the emulsion.

d. Decant extract into a 400 ml beaker. Serological pipets and a pipet aidfiller/dispenser may be used.

e. Repeat the extraction two or more times wrth additional portions of solvent.Decant the solvent after each extraction. If the sample is expected tocontain more than 10% total recoverables, two additional extractions arenecessary. After the final extraction, rinse the pipet into the beaker with afew ml extraction solvent.

f. Add one or two boiling chips and concentrate on the water bath under agentle stream of clean, dry nitrogen to a volume of about 30 ml.

g. Pressure filter into a 50 ml volumetric flask through a Millipore filter equippedwith a 0.5 micron pore membrane. Five grams of anhydrous sodium sulfateis added to the filter assembly to remove any water that has been collected.5 psi is generally used, more pressure may be used if necessary (up to 45psi).

h. Rinse the filter flask and the Millipore filter three times with 3 to 4 ml etherDilute to mark wrth and stopper.

C*GMS

SOP NUMBER SOP020.001 Pag. 4 of 4

7.0 REFERENCES

7.1 Method 3550B. Test Methods for Evaluating Solid Wastes Physical/ChemicaiMethods SW856

7.2 Procedures for glassware cleaning and use of votumetric glassware are describedin "Chemical Technicians' Ready Reference Handbook" (COGNIS, Inc. libraryreference number HTC QD 61.S58).


L-f-'.

, jU/t *f

. /5

V~£r~ **<--, (

/^v A I ^^

f trSz^^-^-e^-^ <3'oi

u/i rt\

UUT

Si/*e>

tv'itlUfc,t

ex

Minnesota Pollution Control Agency Technical Support Memo,

From : Rodolphe Cramail, Engineer AJI** (n ~P-cAndrew Streitz, Hydrogeologist Arz<;

To : Ted Smith, EPA Project ManagerTom Kelley, MPCA Project Leader

Re : Arrowhead Site: Soil Washing Benchscale ResultsDate : 9/2/93

Introduction: highlights on soil washingSection 121b of CERCLA recommends/prefers remedial actions in which treatment"permanently and significantly reduces the volume, toxicity or mobility of hazardoussubstances, pollutants and contaminants" as a principal element. Further, "The offsitetransport and disposal of hazardous substances or contaminated materials without suchtreatment should be the least favored alternative remedial action where practicable treatmenttechnologies are available." Soil washing satisfies these requirements through the reductionof the volume of contaminated soils and the resulting placement of cleaned soils back on thesite.

Soil washing is a liquid-based {often water) process that mechanically separates the differentparticle size classes of a soil, transferring and concentrating the contamination from thewhole soil into the fine fractions which can then be recovered. Therefore it generatescontaminated fines and clean sandy and oversize fractions. This can lead to a considerablereduction in the volume of contaminated material depending on the original fraction of thefines in the total soil because the efficiency of the soil washing process is driven mainly bythe particle size distribution of the soil to be processed as well as by the mobility of thecompounds to be treated.

Status of Soil Washing as Remedial Alternative:Soil washing is an innovative technology which was chosen for remediation (as of August1991) for 16 Super-fund sites and that has been demonstrated under the EPA SITE program(US EPA. "The Superfund Innovative Technology Evaluation (SITE) program : TechnologyProfiles, Fourth Edition."). Though not widely used in the US, at least five remediationcompanies use it regularly in the Netherlands.

Suitability of the Arrowhead site contaminated soils to soil washing treatment:According to EPA guidance (US-EPA, Engineering Bulletin: "Soil washing treatment."EPA/540/2-90/017, September 90) aa it applies to the particle size distribution datagenerated at the Arrowhead site, the soils are amenable to soil washing. The percentage offines observed at the Arrowhead site range from 9 to 28% (table 1), resulting potentially ina volume reduction of 72 to 90%.

Table 1: Currently available particle size distribution dataSource :

Fines %Upper Mesh

EcovaBiostudy:26/7/8/9

<200

BARR/ABBBiostudv:

18<140

CognisPhase 1a:

9<270

CognisPhase 1b:

12Lamotte cl.

CognisPhase 227/28<140

The Arrowhead soils are essentially fill, and therefore primarily sands and gravels with debrisand gross oversize particles also present. For this type of soil, washing is considered agood choice for lead contamination treatment. Vendor and data base information (US-EPAV.I.S.I.T.T. Data Base) is supportive:• Observed particle size distribution of the site soils fits the basic requirements of soil

washing.• TPH, PAH and Lead contamination in soils can be effectively remediated by soil washing

in the range of concentration observed at Arrowhead and down to levels below sitecleanup levels.

As soil washing efficiency is mainly driven by the fines content, it is reasonable to assumethat this process will be rather insensitive to contaminate concentration variation.

Existing data on soil washing efficiency at the Arrowhead site :Within the framework of the lead removal treatability study phase 2, COGNIS performed asoil washing step on a batch scale sample {5 - 6 kg) of Arrowhead soils. The contaminantconcentrations appear to be representative of the fill soils for the entire process area with aTPH content of 4-6%, and a lead content of 1000-2000 ppm. COGNIS was able to achievea 75% volume reduction through emulsifier enhanced soil washing, corresponding to anobserved average particle size distribution of oversize/sand/fines of 30/45/25% respectively.The soil washing step of the benchscale was performed by the Alaskan company BESCORP,whose soil washing process was demonstrated under the EPA SITE program at the AlaskanBattery Enterprises Site in the summer of 1992.

Table 2: Soil Wash results COGNIS phase IISoil Fraction

Total Pb (ppm)TCLP Pb (mg/l)

TPH (%)

Oversizenot analyzednot analyzednot analyzed

Sand222

pass « 1 }0.93

Fines1650

fail (>5)7.9

Oversized was not analyzed because: 1) it is assumed the wash is both more efficient forthis sized particle and because contaminants correlate with available surface area, and 2) ofthe difficulty in sampling and submitting this matrix to analysis.

An oil phase was recovered, but the volume (on the order of 0.01 liter) was too small tosubmit to analysis. COGNIS considers the oil recovered from the large scale remediation ofthe soils to be classed as an off-specification oil. Depending on the final concentration ofPb, a BIF unit can either be paid to burn or given the oil as an alternate fuel.

Wash water was recycled during the process, reaching a TPH concentration at the end ofthe Benchscale of less than 24 ppm.

Full Scale ImplementationBESCORP/COGNIS is currently carrying on a full scale remedial action on Pb contaminatedsoils utilizing this technology at TCAAP (Twin Cities Army Ammunition Plant), an NPLSuperfund Site in Minneapolis.

Relationship with other treatment trains:The selection of soil washing does not preclude the use of any other treatment such as solidphase bioremediation or Pb removal {acid extraction and precipitation of Lead), where soilwashing would be a pretreatment for further remediation. It can also function as the soletreatment prior to landfilling.

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