Method for biologically treating acidic mine wastewater and recovering iron ions and system thereof

Abstract

The invention provides a method and a system for biologically treating acidic mine wastewater and simultaneously recovering iron ions. The method comprises the following steps: (1) carrying out biomineralization on the acidic mine wastewater by acidophilic iron-oxidizing bacteria, carrying out cyclic biological reduction treatment by acidophilic iron-reducing bacteria, introducing the wastewater into an alkali regulating tank, circularly regulating the pH value, and circulating an effluent to a biomineralization treatment unit for cyclic treatment; and (2) after reaction for a period of time,leading the wastewater out from the tail end of the water collecting tank and can be subsequently connected with a lime neutralization treatment system, and recycling jarosite minerals or schwertmannite minerals in the biological mineralization unit. The screened bacteria are indigenous strains existing in the actual mine environment and can be completely suitable for mine wastewater treatment. According to the invention, the precipitation amount of iron in the acid wastewater is increased by adopting circular treatment, and the mine wastewater can completely reach the standard by subsequentlyconnecting lime for neutralizing treatment.

Description

technical field [0001] The invention belongs to the field of waste water treatment, and relates to a method and a system for biologically treating acidic mine waste water and simultaneously recovering iron ions. Background technique [0002] Acid mine drainage (AMD) is a challenging environmental issue currently facing the global mining industry. It is a type of drainage with low pH and high iron ions produced after biological and chemical reactions occur in the mining or waste slag accumulation process of mines. Extremely acidic (pH: 2.0-3.5), rich in sulfate (SO 4 2- : 2000-6000mg / L), high iron content (Fe 2+ or Fe 3+ : 500-4500mg / L), toxic metals (As, Cd, Cu, Pb, Ni, etc.) are typical characteristics of AMD. The direct discharge of AMD seriously threatens the safety of the water and soil environment and the ecosystem around the mining area, causing huge losses to people's production and life. [0003] The neutralization precipitation method is a relatively mature me...

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Problems solved by technology

But this method still has many problems in use: (1) a large amount of iron ions and sulfuric acid that exist in AMD are easy to form precipitation to wrap on lime surface in neutralization process, reduce neutralization efficiency, thereby cause the raising of alkali neutralization reagent dosage (2) A large amount of iron and sulfate ions in AMD are directly precipitated, which is difficult to recycle, resulting in waste of resources; (3) The amount of neutralized waste residue after treatment is large, and the content of toxic metals contained is low, which cannot be recycled, resulting in pollution Difficulty in safe disposal of mud

This method uses acidophilic Thiobacillus ferrooxidans, which can realize the mineralization process under in-situ conditions, but the disadvantages are that the efficiency of biomineralization treatment is low, and the microorganisms are directly applied to wastewater treatment, and there is a problem that microorganisms are easy to lose problems, it is difficult to fully apply to the actual mine wastewater treatment process

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