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Bioremediation
Presentation Authors
Caren Caldwell
Leslie Thompson
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.
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
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
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
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
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.
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.
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
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
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.
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
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.
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
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
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.
Pintail
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
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
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.
