Biotreatment of acidic zinc- and copper-containing wastewater using ethanol-fed sulfidogenic anaerobic baffled reactor


ŞAHİNKAYA E., Yücesoy z.

BIOPROCESS AND BIOSYSTEMS ENGINEERING, vol.33, no.8, pp.989-997, 2010 (Peer-Reviewed Journal) identifier

  • Publication Type: Article / Article
  • Volume: 33 Issue: 8
  • Publication Date: 2010
  • Doi Number: 10.1007/s00449-010-0423-9
  • Journal Name: BIOPROCESS AND BIOSYSTEMS ENGINEERING
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.989-997

Abstract

The treatment of acidic (pH 6.5-3), sulfate- (2-3 g/L), Zn- and Cu- (total metal 0-500 mg/L) containing wastewater was studied in a four-stage anaerobic baffled reactor (ABR) at 35 A degrees C for 250 days. Ethanol was supplemented (COD/SO(4) (2-) = 0.67) as carbon and electron source for sulfate reducing bacteria. Sulfate reduction, COD oxidation and metal precipitation efficiencies were 70-92, 80-94 and > 99%, respectively. The alkalinity produced from sulfidogenic ethanol oxidation increased the wastewater pH from 3.0 to 7.0-8.0. The electron flow from organic oxidation to sulfate averaged 87%. Decreasing feed pH to 3 and increasing total metal concentrations to 500 mg/L did not adversely affect the performance of ABR and sufficient alkalinity was produced to increase the effluent pH to neutral values. More than 99% of metals were precipitated in the form of metal-sulfides. Accumulation of precipitated metals in the first compartment allowed metal recovery without disturbing reactor performance seriously.