Microganisms in the formation of Acid mine drainage and solution of the problem

1. Application of biotechnology for the
management of acid mine drainage
problem in mining sector
Dr. Kamlesh Choure
Associate Professor & Head
Department of Biotechnology
Faculty of Life Sciences and Technology
AKS University, Satna (M.P.)

8. • Mining produces mineral wealth.
• Unscientific exploitation of earth’s resources degrade
land, water and forest cover.
Mining

15. We have shown our intelligence smartly

16. • There are several areas of
environmental concerns in Indian
mining such as cyanide discharge,
disposal of metal containing waste,
organic-ladden effluents and acid
mine drainage (Natrajan, 2008).

17. ACID MINE DRAINAGE

18. Acid mine drainage (AMD)
• Abandoned mines and tailing dumps containing millions of
tonnes of sulfide mineral containing wastes.
• Sulfite bearing metalliferous ores such as Pyrite (FeS2),
Chalcopyrite (CuFeS2), Pyrrhotite (FeS), Arsenopyrite
(FeAsS), Galena (PbS), Sphalerite (ZnS), Pentlantite (FeNiS),
and Cobaltite (CoS) are the serious hazardous minerals present
in deposits and tailing dumps.
• The role of microbe in the AMD is now well established.
• Acidthibacillus group of bacteria are responsible.

19. Effects of AMD
• Biological resources
– Low pH and oxygen content ⇒ water unsuitable for
aquatic life
– Precipitation of Fe(OH)3
• Increased turbidity and decreased photosynthesis
• Gill-clogging, smothering of bottom dwellers and
food supply, and direct toxicity (benthic algae,
invertebrates, and fish)
• Clogging of interstitial pore space in coars aquatic
substrate habitat

20. Effects of AMD (cont’d)
• Biological resources
– Elimination of aquatic plants ⇒ change in channel
hydraulics
– Stress on other biota associated with aquatic habitats
– Low pH Limits species diversity and richness.
– Many plants cannot tolerate high metal concentrations
• Human resources
– Corrosion of pipes, pumps, bridges, etc.
– Degradation of drinking water supplies
– Harm to fisheries

21. OxygenOxygen WaterWater Acid Mine DrainageAcid Mine Drainage
PyritePyrite
Basically, AMD formation is an oxidation processBasically, AMD formation is an oxidation process
Overall Reaction
4FeS2 + 15O2 + 14H2O → 4Fe(OH)3 + 8H2SO4

22. Bacterial Catalization of Oxidation
Sulfur oxidizing microorganisms
 Sulfur exists in different forms of varying redox state
 Microbes can use many of them as substrate, using O2, NO3
-
, Fe3+
as electron
acceptors

23. Objective
• Major objective of this research was isolation of
acidophilic microorganisms that are capable of
oxidizing sulfur and iron usually produce sulfuric
acid resulting into the formation of Acid Rock
Drainage (ARD) or Acid Mine Drainage (AMD)
systems.

24. Materials and methods
• The present study was undertaken to explore the microbial diversity of
acidophilic bacteria in one such AMD samples of coal mine area of
Singrouli, Madhya Pradesh, India
The following solid media were prepared:
• Inorganic media
• Enriched medium
• 10 mM ferrous sulfate–0.02% (wt/vol) yeast extract–basal salts liquid
medium
Medium pH was adjusted initially to pH 2.0. Incubated at 30°C for 7 days.

25. Results
• Several colonies of mesophilic
sulphur oxidizing bacteria and
acidophilic
chemolithoaurotrophic
bacteria were isolated from
sampling sites that were
capable of growing in ferrous
iron as well as elemental sulfur
and various reduced sulfur
compounds
Photoplate 1:
Colonies of mesophilic sulphur oxidizing bacteria and
acidophilic chemolithoaurotrophic bacteria (arrow)

26. Main Treatment Methods
• Preventative measures best approach.
• Altering mine site hydrology.
• Application of organic wastes.
• Application of alkaline materials (Limestone).
• Wetlands.

27. Research Needed
 A low percentage of AMDs have been studied in India.
 Recovery methods can be expensive and time consuming.
 AMDs continue to grow in number even though mining is in
decline.
 Many effects of AMD may yet to be identified and understood.
 Biocontrol of AMDs may be great biotechnological treatment
tool.

28. Sulfate reducing bacteria
• Good method for treatment.
• Require anaerobic conditions which may be limited in well
mixed lakes.
• Increase alkalinity and help eliminate Fe and sulfate.
• Most are heterotrophs which require and may be limited
by organic carbon.

29. Iron Reducers
• Eat Organics, ‘breathe’ Fe3+
, yielding Fe2+
– Iron reducers use organics called
siderophores to solubilize Fe3+
and
bring it inside the cell
– Also use special organics as shuttles,
which actually carry the electron
between the microbe and the solid.

30. Future objective
• To develop a effective technology based on
microbial consortium of sulphate reducing bacteria
and Iron-III reducing bacteria for controlling of
population of acidophiles and bioremediation of
AMD.

31. Conclusions
• AMD is an environmental problem results from the oxidation of pyrite by
bacteria air, and water.
• Oxidation of pyrite decrease pH and increase concentrations of dissolve
metals in water.
• The latter results in the pollution of water, which can be harmful for the
environment and living species.
• Several methods such as wetlands have been done to increase pH and
decrease metal concentrations in water.
• AMD research continues in order to find better ways to mitigate pollution
and reduce the overall effects in the environment such as global warming.

32. Department of
Biotechnology
Faculty of Life Science &
Technology

33. Innovative steps taken for Academic Excellence
•Developed Bioinformatics Facility

34. Innovative steps taken for Academic Excellence
•Maximum practical approach to study any subject has been adopted.

35. Innovative steps taken for Academic Excellence
•Hands on training programs for skill development.
•Regular student seminars and Student minor projects during the
course

36. Symposium/Conferences/Hands-on Workshops

37. Industrial Training

38. Innovative steps taken for Academic Excellence

39. Creation of Facilities in the
Departmental Laboratories
•Microscopes with
•image analysis system
•UV-Visible Spectrophotometer
•Cooling Centrifuge
•Incubators
•Incubator Shaker
•Leminar Air flow
•Oven
•Deep Freeze –200
C
•Freeze 40
C
•Thermocycler
•pH Meter
•Electrophoresis Units
•Water bath
•Electronic balance
•ELISA Reader
•Tissue Culture Racks
•Thermocycler
•UV-Transilluminator
•Semi Automatic Autoclaves
•TDS/Salinity Meter
• Elecrophoresis equipments

41. • Thank you
• AKS University, Satna is gratefully acknowledged for financial
assistance and infrastructure facility.