Full-Scale Electrokinetic-Enhanced Bioremediation (EK-BIO) of a PCE Source in Low Permeability...

FULL-SCALE EK-BIO OF A PCE DNAPL IN CLAY TILL

- RESULTS AFTER YEAR 1½

[email protected] Martin Bymose, NIRAS Uppsala, Oct 15 2014

MARTIN BYMOSE, NIRAS EK-BIO FULL SCALE – RESULTS FROM YEAR 1½ UPPSALA OCT 15 2014 2

EK-BIO TEAM

– NIRAS A/S• Martin Bymose• Charlotte Riis• Dorte Pade

– Geosyntec Consultants, US• Evan Cox• James Wang

– US Army Engineer R&D Center• David Gent

– The Capital Region• Mads Terkelsen

– Contractor• Arkil A/S Miljøteknik• Jes-Tec

3

ELECTROKINETICALLY-ENHANCED BIOREMEDIATION (EK-BIO)

• The challenge of low permeability materials is that most contaminants migrate/diffuse into the low K soils

• Distribution of bioremediation amendments is poor and non-uniform in low K materials

• Non-uniform distribution will prolong remediation and increase costs

• EK-BIO is an approach to meet the challenge of distributing reactants in low-permeable materials

• EK transport is independent on Kh

MARTIN BYMOSE, NIRAS EK-BIO FULL SCALE – RESULTS FROM YEAR 1½ UPPSALA OCT 15 2014

ELECTROKINETIC TRANSPORT

4

An electrical field (DC) is induced in the subsurface

Primary EK-BIO transport mechanisms in clay and silt:

• Electro migration (EM) – migration of charged ions – transport of donor

• Elektro osmosis (EO) – bulk movement of water – transport of biomass


5

THE SITE

Treatment area: Hot Spot IV

PCE DNAPL

10.000-100.000 µg CVOC/L

1.000-10.000 µg CVOC/L

100-1.000 µg CVOC/L

AREA A

AREA B

Natural flow direction

MARTIN BYMOSE, NIRAS

Area 150 m2, depth 8 m

EK-BIO FULL SCALE – RESULTS FROM YEAR 1½ UPPSALA OCT 15 2014

6

PROJECT SCHEDULE

Stage 2

Stage 9

Stage 3

Stage 1

Stage 4

Stage 7

Stage 6

Stage 8

Stage 10

Stage 11

Stage 12

Stage 5

Cycle 1:2012-2014 Cycle 2:2014-2015 Cycle 3:2016-2017

Status today

Injection of biomass in area A

Injection of biomass in area B


• Two treatment areas: alternating active-passive phase of 90 days/ area

• Duration estimated at 3-5 years


7

ELECTRICAL FIELDAREA A – STAGE 1 + 3

Anodes (+)

Cathodes (-)

Injectionwells

Monitoring wells

Electromigra-tion: Donortransport

Elektro-Osmosis: Biomass transport

Stage 1: Operation period dec. 2012 – apr. 2013 Stage 3: Operation period sep. 2013 – dec. 2013


8

ELECTRICAL FIELDAREA B – STAGE 2 + 4

Anodes (+)

Cathodes (-)

Injectionwells

Monitoringwells

Electromigra-tion: Donortransport

Elektro-Osmosis:Biomass transport

Stage 2: Operation period juni. 2013 – aug. 2013 Stage 4: Operation period jan. 2014 – apr. 2014


9

FULL-SCALE EK-BIO - PHOTOS

Katode

Lactate tanks

Lactic acid

NaOH

Injektionsboring

Anode

CathodeInjection well


10

PERFORMANCE MONITORING

Ground waterEach stage: 4 monitoring events• Week 2, 4, and 8: Field

measurements, NVOC• Week 12: Field measurements, NVOC,

VFA, CVOC, methane, ethene, ethane, vcrA, chloride and redoxparameters

Electrode wells

Injection wells

Monitoring wells

Soil coresAfter each cycle Documentation of effect in clay till


11

A

B

A

B

DISTRIBUTION OF DONOR (AS NVOC)- High donor conc in treated areas- Partial depletion during passive stages in cycle 1

STAGE 1 STAGE 3

A

B


BASELINE

A

B

A

B

STAGE 4STAGE 2

STAGE 5

A

B


12

CONTAMINANT COMPOSITION- Dechlorination to VC & ethene in all wells- PCE only present in few wells after stage 5


BASELINE

STAGE 3

STAGE 2

STAGE 1

STAGE 4

Mol

ar fr

actio

nM

olar

frac

tion

STAGE 5


13

DEGREE OF DECHLORINATION- Increasing DOD through stages 1-5

STAGE 1 STAGE 3


BASELINE STAGE 4STAGE 2

A

B

A

B

A

B

A

B

A

B

STAGE 5

A

B


14

CVOC CONCENTRATIONS- Initial cDCE increase + ongoing dechlorination: - PCE release by desorption and dissolution – possible PCE exhaustion

AREA A

AREA B


15EK-BIO FULL SCALE – RESULTS FROM YEAR 1½ BRUXELLES OCT 21 2014

SOIL CORE SAMPLES vs GROUNDWATER- Confirm dechlorination in clay till

- Decrease in total CVOC- Decrease in PCE- Production of cDCE, VC and

ethene- Increase in vcrA in clay samples

from 103/gram to 106/gram- Production of chloride- Soil results support gw results


B: Baseline C1: After cycle 1

B B B

B B B

C1 C1 C1

C1 C1 C1ADJACENT MONITORING WELL

16

KEY CONCLUSIONS 1½ YEAR OF EK-BIO OPERATION• Lactate distribution across the treatment area• VcrA numbers have increased in groundwater and clay across

the treatment area.• Complete dechlorination of PCE to ethene• PCE mass declining• Soil data confirm that dechlorination is occurring in the clay till• 1½ year of full-scale EK-BIO operation show that donor and

biomass are effectively distributed throughout the treatment area enabling complete degradation of PCE DNAPL


17

THANKS FOR YOUR ATTENTION


QUESTIONS?


18

SITE BACKGROUND:EK-BIO TESTING – KEY CONCLUSIONS


Start: 100 mg PCE/kg Day 100:

All PCE degraded to ethene

2009 ERD bench-scale• BIO works, also for

DNAPL• 100% PCE DNAPL

degradation via ERD possible with Dehalococcoides (Dhc) bioaugmentation

2010 EK-BIO lab test• Lactate transport

rate 3.2 cm/day• Increase in vcrA

numbers• PCE dechlorination

to VC and ethene

2011 EK-BIO field pilot test• Lactate transport rate

2.5-5 cm/day• Increase in vcrA in

groundwater and clay• PCE dechlorination to

VC and ethene• PCE desorption and

dissolutionEK-BIO FULL SCALE – RESULTS FROM YEAR 1½ UPPSALA OCT 15 2014

19

REDOX CONDITIONS AND BIOMASS


REDOX CONDITIONS

• pH neutral in monitoring wells

• Strongly reducing conditions: sulfate reduction & methanogenesis

DECHLORINATING BIOMASS (vcrA)

• Increasing and high levels of vcrA (108 -109 /L) in all wells

• A few wells have taken some time to reach high vrcA levels


20

PROCESS MONITORING

SCADA: (Daily)• pH in electrode wells• Recirculation flow• Timer control• Fast reactions on operation failures

Site visits: (bi-weekly)• Visual inspection of system• Refilling of tanks• Current measurements• Measurement of redox parameters


Full-Scale Electrokinetic-Enhanced Bioremediation (EK-BIO) of a PCE Source in Low Permeability...

Science

Transcript of Full-Scale Electrokinetic-Enhanced Bioremediation (EK-BIO) of a PCE Source in Low Permeability...