Performance assessment of S/S Performance assessment of S/S wastewaste--forms: initial results from site forms: initial results from site

characterisationcharacterisation, sampling and testing, sampling and testing

Aurora Antemir

Centre for Contaminated Land RemediationUniversity of Greenwich

a.antemir@gre.ac.uk

Talk outlinesTalk outlines

•• PASSiFyPASSiFy aims and objectivesaims and objectives

•• PASSiFyPASSiFy testing testing programmeprogramme

•• Sites available in the USASites available in the USA

•• Pepper Steel, FloridaPepper Steel, Florida

•• Site historySite history

•• Leaching testsLeaching tests

•• Compliance physical testsCompliance physical tests

•• ConclusionsConclusions

•• AcknowledgementsAcknowledgements

PASSiFy aims and objectives

Aim

TO ADD KNOWLEDGE about the performance over time of S/S wastes by

Examining samples taken from full-scale applications of S/S technology in 3 countries (UK, USA, France)

Identifying critical performance indicators in a detailed chemical, physical and microstructural testing programme

Development of a risk management toolbox for improved stake-holder confidence in S/S

Testing programmeTesting Testing programmeprogramme

REMEDIAL WORKS

In-situ Ex-situ

. . .n YEARSn YEARSSAMPLING

INITIAL TESTINGCompliance tests

Physical Chemical

TESTSagainst

acceptance criteria (IAC)

“transversal”TESTS

e.g.Physical, chemical

microstructurale.g.

leaching testse.g.

UCS, porosity, permeability

Sites available for the PASSiFy project in United States

Sites available for the Sites available for the PASSiFyPASSiFy project in United Statesproject in United States

Sites available in the United States

Site name Date of the remediation Contaminants Stabilising mix Degree of

exposure

Pepper Steel, FloridaFlorida 19881988 PCB, Pb, As 60/40 OPC/PFA(*)

GCL and crushed stone

American Creosote, TennesseeTennessee 1999

Creosote, PAH, PCP, Dioxins

5% OPC, 4.5% PFA, 1.3% powdered carbon (*)

No linerGCL and soil soil capcap

Columbus, Georgia MGP Site, GeorgiaGeorgia 1992 PAHs, BTEX,

cyanideunknown mix2525 % ratio to soil

To be confirmed

Selma Pressure Treating Company 1993

OrganicsOrganics, As, Cr, and Cu

silicate mineral reagents, cement (*)

To be confirmed

Network Underground Quarry (NQ) 1994 TPH

cement 1212% ratio to soil

To be confirmed

90th South Battery Dump 20012001 PbPb, As, As cement + cement

kiln dust (*)To be confirmed

South 8th Street, ArkansasArkansas 2000 Pb, Organics Step 1 – CaCO3

Step 2 – cement (*)No linerNo linerGCL and soil cap

* * 20 % cement ratio to soil 20 % cement ratio to soil ((w/ww/w))

Sites overviewSites overviewSites overview

Sites of different agedifferent age ranging between 5 to 17 years

Different types of contaminantsDifferent types of contaminants

inorganics

organics

Sites located in different geographical regionsdifferent geographical regions, of different geologydifferent geology

Sites having different remediation treatmentsdifferent remediation treatments

Sites with different degrees of exposuredifferent degrees of exposure: capped or exposed

Pepper Steel (PS) site, Florida

SUPERFUND siteCourtesy E. Bates – US EPA

Location and Location and dimensionsdimensions

Former land Former land useuse

ContaminationContaminationDate and type Date and type of remediationof remediation

As, As, PbPb, PCB, PCB19891989

ExEx--situ S/Ssitu S/S

Stabilising mixStabilising mix

FloridaFlorida11 acres11 acres

22--12 feet deep12 feet deep

Steel and Steel and alloy factoryalloy factory

60/40 60/40 OPC/PFAOPC/PFA

(20% ratio to (20% ratio to soil)soil)

Source US EPASource US EPA

PS remedial worksPS remedial works

ContaminantContaminant Concentration in Concentration in prepre--treated soil (treated soil (ppmppm))

Remedial Remedial action levels (action levels (ppmppm))

Pb >> 1000 0.05As >> 5 0.05

CementitiousCementitiousmaterialsmaterials

GCLGCL

CrushedCrushedstonestone

soilsoilPb

PbPb AsPbAsPb

PbPbPb Pb PbPb

PbPb

PbPb PbAsPbPb PbPbAs Pb Treated soilTreated soil

Leaching results at PS Leaching results at PS (IAC)(IAC)University New Hampshire, USAUniversity New Hampshire, USA

Analyte Average (ppm)Arsenic 23.2Barium 128Cadmium 4.58Chromium 25.6Lead 1728Selenium 4Silver 3.18

2003 Total metal concentration Total metal concentration

in treated soil before in treated soil before leaching testsleaching tests

Toxicity Characteristic Toxicity Characteristic Leaching Procedure (TPLP)Leaching Procedure (TPLP) Multiple Multiple ExtractionExtraction Procedure (MEP)Procedure (MEP)

0

1.6

0.20

1

2

3

4

5

1993 2000 2003

Pb c

once

ntra

tion

(ppm

)

Pb threshold (TCLP)

00.1

0.6

00.20.40.60.8

11.2

1993 2000 2003

Pb c

once

ntra

tion

(ppm

)

Pb threshold (MEP)

Levels of As < Detection Limit in TCLP and MEPLevels of As < Detection Limit in TCLP and MEP

Compliance tests at PSCompliance tests at PSUnconfined compressive strengthUnconfined compressive strength

Sample Results (psi)2004 in-situ readings

PS-01 (5 reps) > 600

2003 (ASTM D1633)

PS-01 15.9 *

2000 (ASTM D1633) 7781989 treatment > 20.8

PS-02 679.8PS-03 421.9PS-03 347.2PS-04 149.7

* Fractures were observed when sampling

Compliance tests at PSCompliance tests at PSPermeabilityPermeability

Sample Results

2003 (ASTM D5084) 5 tests

Average 2.5 x 10 -8 m/s

1989 Design target 1 x 10 -7 - 1 x 10 -8 m/s

Range 1 x 10 -7 - 3.6 x 10 -9 m/s

Conclusions & future workConclusions & future work

UndertakeUndertake

After 15 years of service materials still meet the acceptance criteria

showed by the preliminary testing (leaching tests TCLP, MEP and physical

tests)

TRANSVERSAL TESTS

Microstructural Leaching Geotechnical

AcknowledgementsAcknowledgements

Supervisors: Dr. Colin Hills and Dr. Paula CareySupervisors: Dr. Colin Hills and Dr. Paula Carey

And the And the PASSiFyPASSiFy consortiumconsortium

Environmental Geotechnics