1. Selenium Removal from Mine Waters
Raymond J. Lovett, Ph.D.
Environmental Chemist
ShipShaper, LLP
Morgantown, WV

2. SUPPORT
National Mine Land Reclamation Center, West Virginia University
United States Office of Surface Mining
Magnum Coal Company
Catenary Coal

3. Typical Southern West Virginia Mine Water
[Se] = 13 ug/L
[Fe] = 0.15 mg/L
[SO4-2] = 980 mg/L
Alkalinity = 235 mg/L as CaCO3
pH = 7.1

4. Problems Overriding Concern Specific Problems for Treatment
Regulatory limit near 5 ug/L
Specific Problems for Treatment
Low level of Se
Differing chemistries
Selenate, SeO4-2, Se(VI)
Selenite, SeO3-2, Se(IV)

5. Selenium Removal Difficulties
Different dissolved species
No direct precipitation chemistries
Reduction of selenate is difficult (slow)
Sulfate may interfere

6. Treatment System Objectives
Effluent maximally 5 ug/L Se
Low installation cost
Low operating cost
Passive

7. Demonstrated Chemistries
Adsorption or co-precipitation by Fe(III) hydroxides
Biological (bacterial reduction)
Reverse osmosis
Reduction by Fe(0)

8. Reduction with Iron Metal
SeO4-2 +Fe(0) => Fe(II,III) +Se(0)
SeO3-2 +Fe(0) => Fe(II,III) +Se(0)

9. Selenium Species on Iron

10. Field Trial Catenary Coal
Test in a real setting
Real, variable input chemistry
Continuous Se Input

11. Field Trial System

12. Field Trial System

18. Catenary Post Trial 1

19. Catenary Post Trial 2

20. Catenary Post Trial 3

21. Catenary Post Trial 4

22. Catenary Post Trial 5

23. Reduction with Iron Metal
Potential
Removal of selenate and selenite
Passive
Problems
Iron Oxides/ Dissolved Fe, Mn
Exhaustion
Passivation
Expense (surface area)

24. Bacterial Estimated Cost
Flow = 285 gpm
Capital Cost = $7.2 to $10 million
O&M = Unknown

25. Reverse Osmosis Estimated Cost
Flow = 200 gpm
Capital Costs = $1.2 million
O&M = $5.85 million/year

26. Iron Hydroxide Estimated Cost
Flow = 200 gpm
Capital Cost = $0.69 to 1.03 million
O&M = $1.39 million/year

27. Zerovalent Iron Estimated Cost
Flow = 250 gpm*
Capital costs = $478,000
O&M = $150,000 to $300,000
* Gravity flow, includes surge

28. Conclusions
Iron metal removes selenate and selenite, but currently requires long contact times
Manganese and iron generated
Temperature sensitive (?)
Less expensive than other methods