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Biodesulfurization of Flue Gases and Other Sulfate/Sulfite Waste Streams Using Immobilized Mixed Sulfate‐Reducing Bacteria
Author(s) -
Selvaraj Punjai T.,
Little Mark H.,
Kaufman Eric N.
Publication year - 1997
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp970073v
Subject(s) - sulfite , sulfate , sulfate reducing bacteria , flue gas , chemistry , environmental chemistry , streams , waste management , bacteria , sulfur , environmental science , inorganic chemistry , biology , organic chemistry , engineering , computer network , computer science , genetics
Sulfur dioxide (SO 2 ) is one of the major pollutants in the atmosphere that cause acid rain. Microbial processes for reducing SO 2 to hydrogen sulfide (H 2 S) have previously been demonstrated by utilizing mixed cultures of sulfate‐reducing bacteria (SRB) with municipal sewage digest as the carbon and energy source. To maximize the productivity of the bioreactor for SO 2 reduction in this study, various immobilized cell bioreactors were investigated: a stirred tank with SRB flocs and columnar reactors with cells immobilized in either κ‐carrageenan gel matrix or polymeric porous BIO‐SEP beads. The maximum volumetric productivity for SO 2 reduction in the continuous stirred‐tank reactor (CSTR) with SRB flocs was 2.1 mmol of SO 2 /(h·L) . The κ‐carrageenan gel matrix used for cell immobilization was not durable at feed sulfite concentrations greater than 2000 mg/L (1.7 mmol/(h·L) ) . A columnar reactor with mixed SRB cells that had been allowed to grow into highly stable BIO‐SEP polymeric beads exhibited the highest sulfite conversion rates, in the range 16.5 mmol/(h·L) (with 100% conversion) to 20 mmol/(h·L) (with 95% conversion) . The average specific activity for sulfite reduction in the column, in terms of dry weight of SRB biomass, was 9.5 mmol of sulfite/(h·g) . In addition to flue gas desulfurization, potential applications of this microbial process include the treatment of sulfate/sulfite‐laden wastewater from the pulp and paper, petroleum, mining, and chemical industries.