HEAVY METALS REMEDIATION DESIGN- TEMPORARY OR LONG...
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WWW.CERESCORPORATION.COM 1 PRESENTED BY: LOWELL KESSEL EMAIL: [email protected] Heavy Metals Remediation Design: Temporary or Long Term Solutions?
Transcript of HEAVY METALS REMEDIATION DESIGN- TEMPORARY OR LONG...
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PRESENTEDBY:LOWELLKESSELEMAIL : [email protected]
HeavyMetalsRemediationDesign:TemporaryorLongTermSolutions?
Whatismetalsstabilization?Addchemicalreagentstoformmineralsinsoilandaquiferstoreduce:◦ Leachingfromsoil◦ Groundwaterconcentrations◦ Toxicity
Reagentsaretypically:◦ Commonagriculturalandindustrialchemistriescombinedinproprietaryblends
◦ Poselittletonohazardtotheenvironment
◦ Requiressimple(lowtech)equipmentthatislowincost
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StabilizationisaGreenRemediationAlternativeTRADITIONALAPPROACH GREENALTERNATIVE
Excavationofmetals-contaminatedsoilfromsite
Backfillsitewithcleanfill
Disposeashazardouswaste
Haulhazardousmaterialstolimitedlandfilllocations(increasedcarbonfootprint)
Chemicallystabilizemetalstorendernon-hazardous
Potentiallyreuse stabilizedsoil
Disposeasnon-hazmaterial
Moredisposaloptionslocallyforsolidwastemanagement(non-hazardous)
StabilizationChemistryIn-HouseChemicalEngineering+LeachabilityLaboratory:◦ Demonstrateshort- andlong-termstability
◦ Supportreuseofremediatedsoilon-site
◦ Resolvesourceandgroundwaterplumeimpacts
◦ Guidefieldimplementationanddesign
QuickOverviewofProcess1. SiteCharacterization2. TreatmentGoalsIdentification/Establishment3. Treatabilitystudies4. RemedyDesign5. PerformanceTesting/VerificationImplement!
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TestingforRemedyDesignStabilizationdesign◦ Sitecharacterization◦ Treatabilitystudies◦ Enduseevaluation
RemediationgoalsExposurerisksCostimplications
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StabilizationObjectivesDevelopmentSoil/Waste
Off-SiteDisposal On-SiteReuse
Non-hazardousHazardous Covered
/LeachingDirect
exposure
$$$ ReagentSelection*
ReagentSelection*
ReagentSelection*
* Reagent selection based on appropriate leaching lab test procedure, and the best performing, most cost-effective chemistry.
TreatabilityStudyProgram1. Prepareaworkplan2. Collecttestsamples3. CharacterizetheInitialSample
1. HomogenizerawmaterialsoPerformphysicaltesting2. Performchemicaltesting
4. Performtreatabilitytesting1. Identifyappropriatereagents2. Conducttestingbymixingreagentswithcontaminatedmaterialandprepare
formulationsforfurthertesting3. Optimizemixdesign4. SelectionofmixdesignverificationphaseoPreparefinalmixdesignandtest
5. Analyze,AssessandValidateData6. Preparetreatabilitystudyreport
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ApplicationApproachesMethods◦ Injection◦ Mechanicalmixing◦ Permeablereactivebarriers
Reagentscanbeappliedinsitu orexsitu in◦ Dry,granularform◦ Asasolution,orslurry
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TestMethodsvToxicityCharacteristicLeachingProcedure(TCLP).USEPA,SW-846Method1311
vState-specificprocedures(i.e.,CAWET)
vSyntheticPrecipitationLeachingProcedure(SPLP).USEPA,SW-846Method1312
vMultipleExtractionProcedure(MEP).USEPA,SW-846Method1320
vSite-specificleachingprocedures(e.g.SSLPwithgroundwater,wastewater)
vInvitroBioaccessibility (IVBA,EPA9200.2-86,April2012)
vParallelBatchExtractionProcedures(PBEP).USEPA,SW-846Pre-Methods1313,1314,and1315(L:SpartitioningasafunctionofpH)
vASTMMethods.e.g.D3987-85(neutralleaching),D4842-89(monolithleaching),D6234-98(miningwastes)
TestMethodsandTreatmentGoalsToxicityCharacteristicLeachingProcedure(TCLP)SyntheticPrecipitationLeachingProcedure(SPLP)Site-specificleachingprocedures(SSLP)ParallelBatchExtractionProcedures(PBEP)MultipleExtractionProcedure(MEP)- 1,000yrsPhysiologicallyBasedExtractionTest(PBET)
LandDisposal
Usedwhenstabilizedsoilisplacedabovethewatertable
SSLPandPBEPmaybeusedforPRBs/GWorwastewater
PBEBusedinresiliencedesign
Long-termstabilization(1,000yearsorlonger)
Risktohumangastro-intestinaltract
DesignPlanningfortheFutureLongtermsustainabledesignincludesevaluationofpossiblescenarios.v Howwellhaveyoucharacterizedthesite?v Howlikelyareconditionstochange?vWhataboutunforeseencatastrophicevents?v Areyouconsideringresilienceinyourdesign?
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Genericbehaviorsofseveralinorganiccontaminanttypesshowinggeneralizedminima/maximaasafunctionofpH
B-7
Figure B-3. Generic behaviors of several inorganic contaminant types showing generalized minima/maxima as a function of pH.
For organic contaminants, measured LSP concentrations are associated with partitioning between organic and aqueous phases, as well as complexation with dissolved carbon in the aqueous phase. The organic-aqueous partitioning of a contaminant is described in the literature using the octanol-water partitioning coefficient, Kow. This partitioning is relatively tolerant of changes in pH; however, the dissolution of organic carbon, and hence the complexation with organic contaminants, are strongly dependent on pH, especially in the alkaline range. In Figure B-4, the relative concentrations of DOC and total PAHs in a leachate are shown before and after removal of the organic carbon through flocculation.
Figure B-4. pH-dependent leaching of DOC and associated PAH concentrations from contaminated sediment. Source: After Roskam and Comans 2003.
B.4.2 PreMethod 1314
This percolation column method (EPA 2010b) is designed to provide the LSP of constituents as a function of L/S under conditions where water percolates through the solid material.
0 2 4 6 8 10 12 14
Con
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n (lo
g sc
ale)
pH
CationicOxyanionic
Amphoteric
Highly Soluble
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DOC
DOC after flocculation
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s[µ
g/L]
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PAH after flocculation
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DOC after flocculation
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s[µ
g/L]
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ParallelBatchExtractionProcedure(Arsenicinpre-treated(a)andpost-treated(b)coalflyash
TreatedUntreated
by the Missouri University of Science & Technology (CTIS News, vol. 7, no. 2).
LessonsLearnedPOORCSMDEVELOPMENT◦ Lowresolutionsampling◦ Spatialandverticaldelineation
◦ Wronglaboratorytestingprocedures
◦ Sampleintegrity◦ Impropergoalsetting◦ Baselinevsconfirmationsamplingdesign
◦ Materialpropertiesnotconsidered
POORIMPLEMENTATION◦ Notreatabilitystudyorpoorlyperformed◦ Samplecollectionmethod◦ Sampleintegrity
◦ Wrongchemistryorproduct◦ Onesizefitsallsolutionshavehigherfailurerates
◦ PoorMixingDesign/Equipment
◦ PerformanceSamplingandsamplingprocedure
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CaseStudyReviewSustainablelongtermheavymetalsdesign.Goal:ManyhundredsofyearsHeavyMetal:ZincResult:Success!Immediatetreatmentgoalsachieved
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CaseStudy:BrownfieldsRedevelopment - ZincFormerlargeindustrialsiteredevelopedintoresidentialusePetroleumhydrocarbon,chlorinatedsolvent,andzinccontaminationinsoilandgroundwaterNofurtheractionforsoil,continuedgroundwaterandsurfacewatermonitoringPost-development,surfacewaterexceededdischargestandardsforzincInsituremedydevelopedforsaturatedsoilandgroundwater
CaseStudy:BrownfieldsRedevelopment- ZincBench- scaletestswereperformedtodecreasezincfrom30mg/Lto:◦ <0.020mg/Linthebenchstudy
Demonstratedstabilityequivalenttoover400yearswithmodifiedmultipleextractionprocedure(MEP)
MultipleExtractionProcedurePermeableReactiveBarrier.Goalof2mg/Lfrom20mg/L.
Represents480yearsofgroundwaterflow
CaseStudy:BrownfieldsRedevelopment- ZincPilotTesting(6injections,5borings,3monitoringwells)◦ Visualobservationsofreagentdistributioninsoilcores◦ SoilpHandSPLPmeasurementsincores◦ Monitoringwellsgroundwatersamplestoassess“integrated”effectofheterogeneousreagentdistribution
Only2-daysallowedforreagenteffectstopermeatetheinjectionzoneRESULTS- 0.61mg/Linthepilotstudy
CaseStudy:BrownfieldsRedevelopment– ZincPilotstudydeterminationofreagentdistribution
pH in soil
Visual reagent observation
CaseStudy:BrownfieldsRedevelopment - Zinc
CaseStudy:BrownfieldsRedevelopment- ZincFull-scaleimplementationof45,000gallonsofdilutedreagentinjectedin63locationsovera4-weekperiodWithin1yearsurfacewaterzincconcentrationsdecreasedby50to70percentandwithin3yearssurfacewatergoalachieved
LessonsLearned:BrownfieldsRedevelopment- ZincSoilsamples:◦ pH“halos”aroundtheheterogeneousreagentdistribution
◦ 83percentofpost-injectionsoilsamplesSPLP<0.020mg/Lofzinc
Groundwatersamples2of3noted>97percentreductioninzincconcentration1of3notednoconcentrationreduction
ConclusionsSignificantcostsavingscanbeachievedthroughmetalsstabilizationOptionsareavailableforrecyclingandreuseofsoilDesigncanconsiderlongtermsustainabilitySite-specificchemistriesandappropriatetestmethodsmayberequiredtocreategreaterprojectdesignflexibility
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ObrigadoLowellKessel
President
CERESCorporation
714.709.3683
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