What is in news : With an aim to “speed-up” the process of clearing the Ghazipur landfill site, the East Delhi Municipal Corporation on Monday passed a proposal to implement the bio-mining of “50 lakh tonnes” of legacy waste.

MAHITI FOR PRELIMS

BIOMINING

• What – extraction of minerals from ores by using microorganisms.
• The microorganisms actually facilitate the extraction of metals from sulfide or iron-containing ores.
• Process is involved in biomining and it is a combination of microbiology and chemistry.
• Common metals: Metals for which this technique is employed included Copper, Nickel, Zinc, Uranium, Gold and Silver
• Bioremediation is the use of microorganisms (bacteria and fungi) to degrade the environmental contaminants into less toxic or nontoxic forms
• Methods of biomining
  • Bioleaching: Low-grade ore is dumped into a heap called leach pile and then soaked with a weak sulfuric acid wash. Then acid reacts with the ores sulfide matrix and encourages the growth of bacterial strain which starts to degrade ore and releases minerals or metals in fluid form.
  • Bio-oxidation: it is widely used for the extraction of gold from ores. This process involves exposing the ore to bacterial oxidation which degrades the insoluble pyrite and arsenic components as it is a precious metal only removal of interfering metal sulfides from ore. Actually, bio-oxidation leaves metal in solid phase and solution is discarded.