ELECTROCOAGULATION TREATMENT OF HEAVY METALS FROM MINE IMPACTED - - PowerPoint PPT Presentation

▶
electrocoagulation treatment of heavy metals from mine
SMART_READER_LITE
LIVE PREVIEW

ELECTROCOAGULATION TREATMENT OF HEAVY METALS FROM MINE IMPACTED - - PowerPoint PPT Presentation

Jun 16, 2023 102 likes •346 views

ELECTROCOAGULATION TREATMENT OF HEAVY METALS FROM MINE IMPACTED WATER Denney Eames, P.E. & Jacob Aylesworth, EIT IWC 16-45 I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6 Executive Summary

slide-1
SLIDE 1

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

ELECTROCOAGULATION TREATMENT OF HEAVY METALS FROM MINE IMPACTED WATER

Denney Eames, P.E. & Jacob Aylesworth, EIT IWC 16-45

slide-2
SLIDE 2

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Executive Summary

  • Electrocoagulation (EC) introduction
  • History of the technology
  • Overview of the science of electrochemistry
  • Review three mine water treatment case studies for EC treated water
  • Underground mine dewatering
  • Tailings stormwater runoff
  • Smelter environmental cleanup water
  • Review the capital and operational costs associated with these

treatment process

slide-3
SLIDE 3

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Introduction to Electrocoagulation

  • First patented in 1906 by A. E.

Dietrich

  • Original patent was used to treat

bilge water from ships

  • Multiple attempts have been

made to commercialize the technology with varying degrees

  • f success
slide-4
SLIDE 4

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Electrocoagulation Today

  • Electrocoagulation is used in many

industries today

  • Stormwater treatment
  • Environmental remediation
  • Marine Pollution prevention
  • Automotive cleaning
  • Food and beverage
  • Mining
  • Oil & gas
slide-5
SLIDE 5

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Electrocoagulation Process

  • The electrical current releases

positively charged metal ions that attract a disproportionate quantity

  • f negatively charged

contaminants

  • Small particles agglomerate into

larger particles through precipitation and absorption

  • Gas generated at the cathode

assists in separating the lighter coagulated particles and forming a stable floc

slide-6
SLIDE 6

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Fe3+

CL

  • Fe3

+

CL

  • CL
  • CL
  • CL
  • CL
  • CL
  • CL
  • CL
  • Fe3

+

HM HM HM OH

  • OH
  • OH
  • OH
  • OH
  • OH
  • OH
  • OH
slide-7
SLIDE 7

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Fe3+

Less Competition, Higher Potential Energy

Fe3

+

Fe3

+

HM HM HM

Anode + Cathode

OH

  • H

2

H

2

H

2

OH

  • OH
  • OH
  • OH
  • OH
slide-8
SLIDE 8

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Electrocoagulation

Electrocoagulation Effects

slide-9
SLIDE 9

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Electrocoagulation

Electrocoagulation Effects

Gravity/Floatation Separation

Electrocoagulation Makes Particles Larger

slide-10
SLIDE 10

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Electrocoagulation Targets

1. Coagulation of suspended solids 2. Precipitation and agglomeration of dissolved metals 3. De-emulsification

  • f oil and grease

from water

slide-11
SLIDE 11

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Literature

Chemical Treatment

“Alum, lime and/or polymers…tend to generate large volumes of sludge with high bound water content that can be slow to filter and difficult to dewater. These treatment processes also tend to increase the total dissolved solids (TDS) content of the effluent, making it unacceptable for reuse within industrial applications.”*

Electrocoagulation

“The characteristics of the electrocoagulated floc differ dramatically from those generated by chemical coagulation. An electrocoagulated floc tends to contain less bound water, is more shear resistant and is more readily filterable”**

*Benefield, Larry D.; Judkins, Joseph F.; Weand, Barron L. (1982). Process Chemistry for Water and Wastewater Treatment. Englewood Cliffs, NJ: Prentice-Hall. P. 212. **Woytowich, David L.; Dalrymple, C.W.; Britton, M.G. (Spring 1993). “Electrocoagulation (CURE) Treatment of Ship Bilge Water for the US Coast Guard in Alaska”. Marine Technology Society Journal (Columbia, MD: Marine Technology Society, Inc.) 27(1):92.

slide-12
SLIDE 12

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Project Process Flow

slide-13
SLIDE 13

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Mine Water Underground Mine Dewatering

  • Treated at mine

surface

  • 30 days @ 250 gpm
  • Elevated cadmium,

copper, arsenic, lead

slide-14
SLIDE 14

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Data: Underground Mine Dewatering

Analytical Parameter

Average ug/L Standard Deviation ug/L Max/Min ug/L INF EFF % Reduced INF EFF INF EFF Cd 2.1 0.54 74.5% 0.54 0.44 3.7/1.4 1.7/0.14 Cu 22 1.7 92.6% 3.5 1.3 32/16 6.3/0.10 Pb 105 1.4 98.6% 15 1.1 141/60 5.4/0.55 Zn 531 70 86.9% 73 62 660/390 244/10 pH 8.1 8.1 0.0% 0.2 0.2 8.3/7.9 8.3/7.9

# of Samples

27 27 Total Treated Volume: 2,628,600 gallons

slide-15
SLIDE 15

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Tailings Stormwater Runoff

  • Mine water storage

pond

  • 25 days @ 250 gpm
  • Elevated cadmium,

copper, arsenic, lead

slide-16
SLIDE 16

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Data: Tailings Stormwater Runoff

Analytical Parameter

Average ug/L Standard Deviation ug/L Max/Min ug/L INF EFF % Reduced INF EFF INF EFF

Cd

0.44 0.20 55.5% 0.33 0.15 1.3/0.13 0.61/0.03

Cu

4.4 1.6 64.3% 1.6 0.29 9.3/2.8 2.1/1.1

Pb

27 0.48 98.2% 14 0.40 58/12 2.3/0.18

Zn

130 14 89.1% 32 6.9 242/104 37/5.6

pH

8.0 8.0 0.0% 0.2 0.2 8.2/7.8 8.2/7.8

# of Samples

23 23 Total Treated Volume: 1,930,200 gallons

slide-17
SLIDE 17

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Smelter Site Environmental Cleanup Water

  • Mine water storage pond
  • 12 days @ 100 gpm
  • Elevated cadmium,

copper, arsenic, lead

  • pH treatment (raised to 8.6

after EC)

slide-18
SLIDE 18

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Data: Smelter Environmental Cleanup Water

Analytical Parameter

Average ug/L Standard Deviation ug/L Max/Min ug/L INF EFF % Reduced INF EFF INF EFF Cd 2,654 12 99.5% 1,755 9.1 7,107/864 34/6 Cu 216 3.8 98.2% 211 1.0 772/34 6/3 Pb 39,932 37 99.9% 40,594 27 147,959/ 3,341 105/6 Zn 10,472 36 99.7% 5,465 17 22,981/ 2,212 58/15 pH 7.6 8.6

  • 13.1%

0.3 0.3 7.9/7.3 8.9/8.3

# of Samples

10 10 Total Treated Volume: 375,900 gallons

slide-19
SLIDE 19

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Capital Costs 6,000 gpm: Water Treatment Plant

Capital Cost Item Cost Engineering $425,000 Process Equipment $8,624,000 Facility, Infrastructure & Installation $2,493,000 Management, Supervision & Commissioning $357,000 Total $11,899,000

slide-20
SLIDE 20

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Operational Costs for a 6,000 gpm: EC Water Treatment Plant

Operational Cost Item $/1000 gallon Annual Cost*

Consumables (EC Cells, UF Membranes, Misc.) $1.252 $3,255,200 Power ($0.07/KWH) $0.272 $707,200 Operations Labor $0.162 $421,200 Total $1.686 $4,383,600

* Estimated annual cost based on treating 2.6 billion gallons per year

slide-21
SLIDE 21

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Operational Costs for a 6,000 gpm: Chemical Water Treatment Plant*

Note: Capital cost range was estimated at $10,300,000 to $15,700,000 * Estimated annual cost based on treating 2.6 billion gallons per year

Operational Cost Item $/1000 gallon Annual Cost*

Consumables (Chemicals, Filters, Misc.) $0.879 $2,285,400 Power ($0.07/kWh) $0.215 $559,000 Operations Labor $0.162 $421,200 Total $1.256 $3,265,600

slide-22
SLIDE 22

I N T E T E R N R N A T I T I O N A L W A T E R C O N F E R E N C E E 2 0 1 6 0 1 6

Conclusions

  • Capital cost for an EC and chemical plant were equivalent
  • EC advantages
  • Full compliance demonstrated in heavy metal reduction
  • Passed all aquatic toxicity testing
  • Reduced sludge/tailings production
  • EC disadvantage cell cost
  • 34% higher operational cost compared to chemical
  • The cost of the EC cell was the majority of the cost
  • Designing a less expensive EC cell is the key to lowering operational costs