An integrated green methodology for the continuous biological removal and fixation of arsenic from acid wastewater through the GAC-catalyzed As(III) oxidation

Silvia Vega-Hernandez, Irene Sanchéz-Andrea, Jan Weijma*, Cees J.N. Buisman

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Herein we report the findings of an integrated green process for the continuous oxidation and biomineralization of the most toxic As(III) from acidic streams using a laboratory-scale airlift bioreactor operated at thermoacidophilic conditions and fed with Fe(II) as electron donor. As(III) oxidation catalyzed by granular activated carbon (GAC), biological Fe(II) oxidation and scorodite crystallization took place simultaneously in the reactor, allowing the treatment of influent solutions containing 0.65 g·L−1 As(III). At a hydraulic retention time of 2.2 days, a stable arsenite oxidation efficiency of 99% was achieved, while the removal of total arsenic was 93%. Scorodite was yielded as the main solid product whose physical characteristics such as average size (250 µm) and the developed crystalline structure allowed the easy harvesting from the reactor and reflected the high stability by the low arsenic release of 0.4 mg.L−1 after 60 days of leaching. The analysis of the microbial composition in the reactor suspension and the precipitates indicated the dominance of thermoacidophilic archaeon of the genus Acidianus. Similarly, the attachment of microorganisms to the precipitates observed by scanning electron microscopy, suggested that the precipitation in our system was biologically mediated. The simultaneous arsenic oxidation and removal through catalyzed oxidation and biological processes provide the basis for a new and cost effective green methodology for arsenic fixation from acid As(III)-containing wastewaters.

Original languageEnglish
JournalChemical Engineering Journal
DOIs
Publication statusE-pub ahead of print - 20 Nov 2020

Keywords

  • Acidianus, Activated carbon
  • Airlift Reactor, Arsenite oxidation
  • Scorodite

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