results from a bench scale passive treatment system

Results from a Bench Scale Passive Treatment System Designed for Removing Sulfate at a Site on Vancouver Island, BC

Presented by,Eric Blumenstein, PE, Golder Associates Inc.

Presentation Overview

Site Location / Background Desires / Needs of Site Traditional Sulfate Removal Technologies Biological Sulfate Removal Bench Testing Construction (March 2011) Bench Testing Results (Summer 2011) Consideration for Demonstration System Design Demonstration System Design Overview Path Forward

Site Location / Background / Needs Underground coal mine

(not hard rock) Active workings Inactive workings Seep into freshwater lake Mining influenced water:

Sulfate Iron Arsenic

Desire for: Low long-term operating

and maintenance costs Operate in cool weather Fit on available land

SULFATE REMOVALTECHNOLOGIES

Traditional Sulfate Removal Technologies

Reverse Osmosis (RO) Membrane Filtration: Proven technology Capital cost Operating and

maintenance cost Labor Chemicals Power Equipment

maintenance Brine production /

disposal

Traditional Sulfate Removal Technologies Chemical Precipitation

Barium chloride Lime Proven technology Capital cost Operating and

maintenance cost Labor Chemicals Power Equipment

maintenance Sludge production /

disposal

Potential New Sulfate Removal Technology

Biological sulfate removal: Active or passive Not a new concept Biochemical reactors (BCR):

Sulfate reducing bioreactors (SRBR)

Succesive alkalinity producing systems (SAPS)

Reducing alkalinity producing sytsems (RAPS)

Limitations: Sulfate reduction is limited

by carbon availability Need to sequester reduced

sulfate

WATER SURFACE

DISCHARGE

DRAINAGE SYSTEM

ORGANIC MATTER &LIMESTONE MIX

(SUBSTRATE)

INFLOW


Sulfate biologically reduced to sulfide: Some sulfide forms metal precipitates (metal sulfides) Some adsorbs to surface area on substrate Some sulfide leaves the BCR as sulfide anion or hydrogen sulfide

Excess sulfide in BCR effluent can: Cause health and safety

issue and Convert back to sulfate

upon leaving cell and being re-oxidized

Brock Biology of Microorganisms, 10th Edition


Options for “sequestering” excess sulfide: Harvest reduced sulfate in BCR effluent (difficult to design and

extensive O&M) Add source of sacrificial iron (sulfide anion binds to iron cation and

form iron sulfide precipitate): Add iron prior to BCR Mix iron into BCR substrate Add iron to BCR effluent

BENCH SCALE BIOCHEMICAL REACTOR CONSTRUCTIONMarch 2011

Bench Scale Design / Construction

CELL MIXTURES ON AN AS RECEIVED BASISMaterial Cell 1 Cell 2 Cell 3 Cell 4 Cell 5

Wood Chips 74.7% 59.7% 53.7% 50.7% 74.7%Sawdust 0% 15% 0% 0% 0%

Hay 10% 10% 10% 10% 10%Limestone Chips 15% 15% 10% 7% 15%Natural Iron Ore 0% 0% 0% 32% 0%

Hedin Iron 0% 0% 26% 0% 0%Animal Manure

(Inoculum) 0.3% 0.3% 0.3% 0.3% 0.3%

Total 100% 100% 100% 100% 100%

Logic Baseline 1Woodchips

Baseline 2Woodchips +

Sawdust

Hedin IronFe(OH3)

Natural Iron Ore40% Iron

Baseline 1Woodchips


BCR1BCR2 BCR3

BCR4BCR5 BCR6

BENCH SCALE BIOCHEMICAL REACTOR RESULTSMarch – September 2011

Bench Scale Testing Periods Initial Incubation Period (31 March – 6 April) Primary Start-up Period (7 April – 12 May) Second Incubation Period (13 May – 8 June) Second Start-up Period (9 June – approximately 7 July) Steady-State Operations (approximately 7 July – 1 September)

Bench Scale Results – Temperature

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-112.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

22.0

BCR INFBCR1 EFFBCR2 EFFBCR3 EFFBCR4 EFFBCR5 EFF

Date

deg.

C

Bench Scale Results – pH

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-114.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0


Date

Stan

dard

Uni

ts

Bench Scale Results – ORP

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11-400

-300

-200

-100

0

100

200

300


Date

mV

Bench Scale Results – Flow Rate

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-110

2

4

6

8

10

12

14


Date

L/da

y

Bench Scale Results – Alkalinity

7-Apr

-11

16-A

pr-11

25-A

pr-11

4-May-1

1

13-M

ay-1

1

22-M

ay-1

1

31-M

ay-1

1

9-Jun

-11

18-Ju

n-11

27-Ju

n-11

6-Ju

l-11

15-Ju

l-11

24-Ju

l-11

2-Aug

-11

11-A

ug-11

20-A

ug-11

29-A

ug-1

1

7-Sep-

11

16-S

ep-11

25-S

ep-11

0

200

400

600

800

1,000

1,200

1,400

1,600


Date

mg/

L

Bench Scale Results – Sulfate (full test)

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11

22-Sep-110

500

1,000

1,500

2,000

2,500

3,000


Date

mg/

L

Bench Scale Results – Sulfate (steady state)

9-Jun-11

23-Jun-117-Jul-11

21-Jul-11

4-Aug-11

18-Aug-11

1-Sep-11

15-Sep-11

29-Sep-110

200

400

600

800

1,000

1,200


Date

mg/

L

Bench Scale Results – Sulfate Reduction (full)

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11-1.000

-0.800

-0.600

-0.400

-0.200

0.000

0.200

0.400

0.600

BCR1BCR2BCR3BCR4BCR5

Date

mg/

L

Bench Scale Results – Sulfate Reduction (steady state)

9-Jun-11

15-Jun-11

21-Jun-11

27-Jun-113-Jul-11

9-Jul-11

15-Jul-11

21-Jul-11

27-Jul-11

2-Aug-11

8-Aug-11

14-Aug-11

20-Aug-11

26-Aug-11

1-Sep-11

7-Sep-11-0.300

-0.200

-0.100

0.000

0.100

0.200

0.300

0.400

0.500

0.600

BCR1BCR2BCR3BCR4BCR5

Date

mg/

L

Bench Scale Results – Sulfide

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11

22-Sep-110.001

0.010

0.100

1.000

10.000

100.000

1,000.000


Date

mg/

L

Bench Scale Results – Biochemical Oxygen Demand (BOD)

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11

22-Sep-110

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000


Date

mg/

L

Bench Scale Results – Pore Volumes Treated

Bench Scale Results – Arsenic

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11

22-Sep-110.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70


Date

mg/

L

Bench Scale Results – Iron

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11

22-Sep-110.0

0.1

1.0

10.0

100.0

1,000.0


Date

mg/

L

Bench Scale Results – Manganese

7-Apr-11

21-Apr-11

5-May-11

19-May-11

2-Jun-11

16-Jun-11

30-Jun-11

14-Jul-11

28-Jul-11

11-Aug-11

25-Aug-11

8-Sep-11

22-Sep-110.00

0.00

0.01

0.10

1.00

10.00

100.00

1,000.00


Date

mg/

L

Bench Testing Conclusions Each of the five BCR cells demonstrated that sulfate can be removed to

the levels desired (>50% removal) Each of the five BCR cells demonstrated sulfate removal at the

maximum possible rate (0.20 mol/m3/day) When flow rate sent to BCR3 and BCR4 was doubled, sulfate removal

also doubled (0.40 mol/m3/day) While BCR3 and BCR4 provided acceptable sulfide sequestration in

situ, iron levels dropped throughout testing, leading to concerns about iron longevity (6 months – 3 years)

Because of a variety of nuisance parameters present in BCR effluent (BOD, TOC, arsenic, manganese, etc.), it is necessary to include an aerobic polishing step in a demonstration/full-scale system

Arsenic and manganese levels may increase in BCR cell, another reason why an aerobic polishing step is required

Maximum operational flexibility must be included (bypass piping)

DEMONSTRATION SYSTEM DESIGNFall 2011

Demonstration System – Flow Schematic

Demonstration System – General Piping Arrangement

Demonstration System – BCR Cell

Demonstration System – Aerobic Polishing System

Demonstration System – Path Forward

Construction to begin in late April, complete in June Incubation for two weeks during June Begin minimum of one year demonstration testing period Move forward to full-scale system (incorporating demonstration system) Looking into testing / developing biological sulfate reduction process:

Fully passive system (no pumping, passive aeration) Hybrid system (minimal power and O&M requirement) Fully active system (ICB fixed-film media with carbon/nutrient

dosing)

Future of Biological Sulfate Removal

THANK YOU!Co-author Jim Gusek

[email protected]

results from a bench scale passive treatment system

Documents

sulfate reduction

bcr substrateadd iron

substratesome sulfide

form iron sulfide precipitate

iron cation

bcrmix iron

bench testing results

bcr effluent difficult