Transcript
Page 1: Bugs Can Do Anything

Bioremediation

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Presentation Authors

Caren Caldwell

Leslie Thompson

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Pintail Systems, Inc. was founded in 1987 by Leslie Thompson

Primary focus was on cyanide detoxification in gold and silver heap leach pads using native bacteria cultures.

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Bioremediation is not new. Traditionally, nutrients are added to the contamination site and everyone hopes for the best. This is very slow if it works at all.

What Makes PSI’s bioremediation process

successful where others fail?

WE OPTIMIZE THE PROCESS

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PSI’s Bio-Augmentation Process Traditional Bio-Stimulation

Active Process Passive Process

Use bacteria cultures isolated from the contaminated site.

Assume that there are effective bacteria colonies at the site

Isolated cultures are tested for treatment efficiency in the lab before application at the site. Nutrients are also optimized for culture growth.

Nutrients are added to the site and the assumption is that those nutrients will stimulate the growth of effective bacteria cultures.

Effective cultures are grown to high concentrations using optimized nutrient formulations and applied to the contaminated site.

Added nutrients stimulate growth of both potentially effective bacteria colonies as well as ineffective colonies. That causes competition for nutrients and limits the growth of effective colonies.

New cultures are added to the site on a regular basis improving treatment efficiency.

Fast and highly efficient Slow if it works at all

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38.4 40.3 32.4 38.424

38.4

0.110.08

0.01

0.1

1

10

100

0.1 0.3 0.5 0.6 0.7

MG

/L T

ota

l C

ya

nid

e

Tons of Solution per Ton of Ore

Nutrient Stimulation PSI's BioAugmentation

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In microbial detoxification of heap leach pads, cultures can be applied directly to the heap in the same way cyanide was added during production.

The cultures are set up in a staged culturing system located at the site

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Staged culturing systeminside the “Bug Ranch” at the Yellow Pine Mine

Cultures are monitored on a regular basis for culture health and effectiveness. Adjustmentsare made as necessary.

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05

101520253035404550

1

29

25

50

59

71

85

94

107

114

121

128

136

146

155

WA

D C

ya

nid

e

Time, Days

Heap Bio-DetoxWAD Cyanide in Heap Effluent Solutions

1.3 million ton heap detox at the Yellow Pine Mine. WAD cyanideLocated in Idaho with Alpine Conditions. Environmentally sensitive area.

1.2 million ton heap detox at Cyprus Copperstone. WAD cyanide and total cyanide.Located in the Arizona desert.

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Treatment Type

Ionic Cyanide

WAD Cyanide

Ferro Cyanide

Thiocyanate

Alkaline Chlorination

Yes Partial No Partial

Peroxide Yes Yes Partial No

Ion Exchange No Yes Yes Possible

Natural Degradation

Yes Partial No No

PSI Bio-Processes

Yes Yes Yes Yes

Sulfur Dioxide

Yes Yes Partial No

Ref. Cyanide From Mineral ProcessingJ.L. Huiatt, ET AL. Editors

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Volunteer revegetation on the Ortiz waste rock dump after bio-treatmentDesert climate

Volunteer revegetation on the sides of the Yellow Pine Mine after bio-treatment.Alpine climate.

Bugs the Ultimate Solution

Bioremediation in Mining: Remediation

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0.622

0.398

0.105

0.488

0.005

0.2470.046 0.054

0

0.2

0.4

0.6

0.8

Cadmium Chromium Selenium Silver

MG

/L

Before Treatment

After Treatment

0.978

2.07

0.1860.005

0

0.5

1

1.5

2

2.5

Iron Mercury

MG

/L

9.15

4.16

0.334 0.0070

5

10

Copper Zinc

MG

/L

Reduction of metals in heap leachate solution in a 2.5 million ton heap before and afterBio-treatment.

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0.35

0.12 0.18

0.0003

0.059 0.07

0

0.1

0.2

0.3

0.4

Mercury Arsenic Copper

MG

/L

Before Treatment

After Treatment

0.94

2.44

0.70.38

0.01 0.120

0.5

1

1.5

2

2.5

3

Zinc Silver Selenium

MG

/L

Reduction in metals in heap leachate solution from a 140,000 ton heap near Gabbs, Nevada

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In analytical work done by Dr. Jeffrey Steiner at City College of New York, it was found that bacteria cultures catalyze the formation of minerals in Bio-treated heaps or process solutions. Mineral formation “locks up” leachable metals. Dr. Steiner’s work was done on Bio-treated ore from the Summitville Mine. This explains the reduction in leachable metal from heaps treated with PSI’s Bio-Processes.

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23

6.31.27 0.30

10

20

30

Nitrate Flouride

MG

/L

100,000 ton heap located in South Dakota. Leachate solution before and after Bio-treatment

420

120

2.5 0.520

100

200

300

400

500

Arsenic Copper

MG

/L

17.9

14.6

3.740.11 0.050.01

0

5

10

15

20

Total Cyanide WAD Cyanide Mercury

MG

/L

Before Treatment

After Treatment

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1800 TON PILOT HEAP

CYANIDE IN HEAP LEACHATE SOLUTIONS

Total CN WAD CN

time, days

0

7

14

21

28

35

41

53

63

74

84

95

105

116

127

137

0.01

0.1

1

10

100

1000

1800 Ton Test HeapNitrates vs Time

nitrate

time, days

0

7

14

21

28

35

41

53

63

74

84

95

105

116

127

0

20

40

60

80

100

120

140

1800 Ton Test Heap

Copper in Leachate Solutions

copper

time, days

0

7

14

21

28

35

41

53

63

74

84

95

105

116

127

137

00.5

11.5

22.5

33.5

44.5

5

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The McCoy Cove Mine was used as an EPA/MWTPP test site to demonstrate the removal of cyanide and leachable metals from mine water using a filtration system with immobilized bacteria.

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Pintail

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332

179255

882

46.8 5.184.9

15.40

200

400

600

800

1000

Arsenic Mercury Selenium Silver

UG

/L

Untreated Influent

Treated Effluent

233

25

0

100

200

300

WAD Cyanide

MG

/L

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Simultaneous Denitrification and Cyanide Detoxification of process solution in a bio-reactor

246 254

33

0

50

100

150

200

250

300

WAD Cyanide

MG

/L W

AD

Cy

an

ide

Influent Preg Solution Untreated Preg Control

Treated Preg Solution

30.4 30.5

1.63

0

5

10

15

20

25

30

35

Nitrate

MG

/L N

itra

te

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All of the data in this presentation is the result of using bacteria native to the contaminated site. By using native bacteria adapted to the conditions at the site, we have been able to conduct successful bioremediation projects located in a wide variety climates, from alpine to desert.

We have also been able to remediate a wide range of contaminants with one treatment, saving time and money.


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