A dicyclic-type electrode-based biofilm reactor for simultaneous nitrate and Cr(VI) reduction

Bioprocess Biosyst Eng. 2019 Jan;42(1):167-172. doi: 10.1007/s00449-018-2020-2. Epub 2018 Oct 5.

Abstract

A dicyclic-type electrode-based biofilm-electrode reactor (BER) was investigated for simultaneous removal of nitrate and Cr(VI). In the absence of Cr(VI), almost complete denitrification of 50 mg/L NO3--N was achieved at a very low C/N ratio of 0.8 with the optimal current of 50 mA. Cr(VI) was removed by biological reduction and co-precipitation when Cr(VI) was taken as the only electron acceptor, and the removal efficiencies of Cr(VI) were 99.8%. In the coexistent system of nitrate and Cr(VI), nitrate removal was the result of the cooperation of hydrogenotrophic denitrification and heterotrophic denitrification. The methanol and H2 were also used as electron donors for biological reduction Cr(VI). The denitrification process was slightly inhibited by 1.00 mg/L Cr(VI) and 94.15% removal efficiency was achieved at current = 50 mA and HRT = 8 h. The present results show that the biofilm-electrode reactor is an effective way to simultaneous remove co-contaminants.

Keywords: Biofilm-electrode reactor; Cr(VI) reduction; Denitricfication; Mechanism.

MeSH terms

  • Biofilms*
  • Bioreactors*
  • Biotechnology / methods*
  • Chromates / chemistry
  • Chromium / chemistry*
  • Denitrification
  • Electrodes*
  • Equipment Design
  • Groundwater
  • Heterotrophic Processes
  • Nitrates / chemistry*
  • Nitrogen / chemistry
  • Sewage
  • Water Pollutants, Chemical
  • Water Purification

Substances

  • Chromates
  • Nitrates
  • Sewage
  • Water Pollutants, Chemical
  • Chromium
  • chromium hexavalent ion
  • Nitrogen