Simultaneous removal of nitrate and heavy metals in a continuous flow nitrate-dependent ferrous iron oxidation (NDFO) bioreactor

Kazuki Jokai, Tomomi Nakamura, Satoshi Okabe, Satoshi Ishii

Research output: Contribution to journalArticlepeer-review

Abstract

Nitrogen and heavy metals can co-occur in various industrial wastewaters such as coke-oven wastewater. Removal of these contaminants is important, but cost-efficient removal technology is limited. In this study, we examined the usefulness of nitrate-dependent ferrous iron oxidation (NDFO) for the simultaneous removal of nitrate and heavy metals (iron and zinc), by using an NDFO strain Pseudogulbenkiania sp. NH8B. Based on the batch culture assays, nitrate, Fe, and Zn were successfully removed from a basal medium as well as coke-oven wastewater containing 5 mM nitrate, 10 mM Fe(II), and 10 mg/L Zn. Zinc in the water was most likely co-precipitated with Fe(III) oxides produced during the NDFO reaction. Simultaneous removal of nitrate, Fe, and Zn was also achieved in a continuous-flow reactor fed with a basal medium containing 10 mM nitrate, 5 mM Fe(II), 4 mM acetate, and 10 mg/L Zn. However, when the reactor is fed with coke-oven wastewater supplemented with 10 mM nitrate, 5 mM Fe(II), 4 mM acetate, and 10 mg/L ZnCl2, the reactor performance significantly decreased, most likely due to the inhibition of bacterial growth by thiocyanate or organic contaminants present in the coke-oven wastewater. Use of mixed culture of NDFO bacteria and thiocyanate/organic-degrading denitrifiers should help improve the reactor performance.

Original languageEnglish (US)
Article number127838
JournalChemosphere
Volume262
DOIs
StatePublished - Jan 2021

Bibliographical note

Funding Information:
This work was supported, in part, by Steel Foundation for Environmental Protection Technology, Japan, and by the Minnesota's Discovery, Research and InnoVation Economy (MnDRIVE) initiative of the University of Minnesota.

Funding Information:
This work was supported, in part, by Steel Foundation for Environmental Protection Technology, Japan , and by the Minnesota’s Discovery, Research and InnoVation Economy (MnDRIVE) initiative of the University of Minnesota .

Publisher Copyright:
© 2020 Elsevier Ltd

Keywords

  • Coke-oven wastewater
  • Denitrification
  • Heavy metals
  • Nitrate-dependent ferrous iron oxidation

PubMed: MeSH publication types

  • Journal Article

Fingerprint

Dive into the research topics of 'Simultaneous removal of nitrate and heavy metals in a continuous flow nitrate-dependent ferrous iron oxidation (NDFO) bioreactor'. Together they form a unique fingerprint.

Cite this