Calcium removal from industrial wastewater by bio-catalytic CaCO3 precipitation

✍ Scribed by Frederik Hammes; Arsène Seka; Kris Van Hege; Tom Van de Wiele; Jan Vanderdeelen; Steven D Siciliano; Willy Verstraete

• Book ID: 102326540
• Publisher: Wiley (John Wiley & Sons)
• Year: 2003
• Tongue: English
• Weight: 242 KB
• Volume: 78
• Category: Article
• ISSN: 0268-2575
• DOI: 10.1002/jctb.840

✦ Synopsis

Abstract

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 mM 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 mM. 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