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Effective bioremediation of Cu(II) contaminated waters with immobilized sulfate‐reducing bacteria‐microalgae beads in a continuous treatment system and mechanism analysis
Author(s) -
Li Yongchao,
Yang Xiaoyan,
Geng Bing,
Liu Xue
Publication year - 2018
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5513
Subject(s) - sulfate reducing bacteria , bioremediation , chemical oxygen demand , sulfate , chemistry , wastewater , bioreactor , effluent , biochemical oxygen demand , environmental chemistry , pulp and paper industry , contamination , environmental engineering , environmental science , organic chemistry , ecology , engineering , biology
BACKGROUND Microalgae which have greater biodegradable fractions than other organics were chosen as a carbon source for sulfate‐reducing bacteria (SRB). Immobilized SRB–microalgae beads were then prepared and used for bioremediation of synthetic copper mine wastewater. RESULTS Hydrolysis fermentation of the microalgae was observed and it was noted that the microalgae were first degraded to volatile fatty acids by co‐existing fermentative bacteria; they then served as a carbon source for SRB. Freshly prepared immobilized SRB beads not only possessed high mechanical strength and mass transfer ability, but also showed better sulfate reduction than that of suspended SRB. Immobilized SRB ‐ Scenedesmus obliquus beads packed in the upflow bioreactor were suitable for the treatment of copper mine wastewater, as shown by the high removal efficiency of their sulfate (182.17 mg SO 4 2‐ g ‐1 microalgae day ‐1 ) and copper ions (45.28 mg Cu 2+ g ‐1 microalgae day ‐1 ), and low discharge of chemical oxygen demand. After the reaction, metal sulfides were not produced on the bead surfaces, but likely within them. CONCLUSIONS The anaerobic bioreactor, filled with immobilized SRB‐ Scenedesmus obliquus beads, demonstrated excellent removal efficiency and low discharge of chemical oxygen demand, which may provide a promising strategy for dealing with heavy metal pollution in water. © 2017 Society of Chemical Industry