Conversion of inorganic ions to metal sulfides by microorganisms
OwnerNathaniel W. Revis, Tanya R. Osborne +1inventors
InventorsNathaniel W. Revis, Tanya R. Osborne, Charles T. Hadden
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Abstract
This invention relates to a process for reducing the concentration of heavy metal ions in an aqueous waste solution, comprising the steps of: (a) contacting the aqueous waste solution with a mixed culture of Citrobacter freundii and a dissimulatory sulfate reducer, in the presence of nutrient sufficient to satisfy the nutritional requirements of the mixed culture, for a time sufficient to produce sulfide ions from a sulfide-ion precursor in the aqueous waste solution or nutrient and to precipitate the heavy metal ions in the form of corresponding sulfides and (b) removing the thus-precipitated sulfides from the waste solution.
Claims23
A process for reducing the concentration of heavy metal ions in an aqueous waste solution, comprising the steps of:
- (a) contacting the aqueous waste solution with a mixed culture of Citrobacter freundii and a dissimulatory sulfate reducer in the presence of nutrient sufficient to satisfy the nutritional requirements of the mixed culture for a time sufficient to produce sulfide ions from sulfide-ion precursors in the aqueous waste solution or the nutrient and to precipitate the heavy metal ions in the form of corresponding sulfides and
- (b) removing the thus-precipitated sulfides from the waste solution.
A process for removing heavy metal, sulfur dioxide or sulfur trioxide contaminants from stack gases comprising the steps of
- (a) passing the stack gases into a mixed culture of Citrobacter freundii and a dissimulatory sulfate reducer, in the presence of nutrients sufficient to satisfy the nutritional requirements of the mixed culture;
- (b) contacting the thus-produced mixture of culture and dissolved or entrained stack gas components for a time sufficient to convert sulfur dioxide, sulfur trioxide or other sulfide precursors in the stack gases or the nutrient to sulfide;
- (c) precipitating heavy metals as corresponding sulfides;
- and
- (d) removing the thus-precipitated metal sulfides from the mixture of culture and dissolved or entrained stack gas components.
Dependencies are inferred from the claim text.