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Calcium removal from industrial wastewater by bio‐catalytic CaCO 3 precipitation
Author(s) -
Hammes Frederik,
Seka Arsène,
Van Hege Kris,
Van de Wiele Tom,
Vanderdeelen Jan,
Siciliano Steven D,
Verstraete Willy
Publication year - 2003
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.840
Subject(s) - effluent , wastewater , chemistry , calcium carbonate , calcium , urea , precipitation , industrial wastewater treatment , calcareous , pulp and paper industry , sedimentation , hydraulic retention time , environmental chemistry , waste management , environmental science , environmental engineering , biochemistry , geology , organic chemistry , paleontology , physics , sediment , meteorology , engineering
High concentrations of soluble calcium in industrial wastewater present problems due to the calcification of downstream processing. The current trend towards circuit closure and increased water re‐use will escalate this problem. We investigated ureolytic microbial carbonate precipitation as a novel process for removing excess calcium from industrial effluents. Two laboratory‐scale reactors, both with a hydraulic retention time of 8 h, were fed with 1.8 dm 3 of anaerobic effluent (about 11 m M Ca 2+ ) from a paper recycling plant. Both reactors were inoculated with pre‐cultivated calcareous sludge and the treatment reactor was additionally dosed with urea to a final concentration of 8.3 m M . Even though the anaerobic wastewater was saturated as such with respect to CaCO 3 , urea addition and hydrolysis was shown to be a pre‐requisite for precipitation. Almost all (85–90% w/v) of the soluble calcium was precipitated as CaCO 3 and removed through sedimentation in the treatment reactor. This bio‐catalytic process presents an uncomplicated and efficient method for the removal of calcium from industrial wastewater. Copyright © 2003 Society of Chemical Industry