Sequential removal of selenate, nitrate and sulfate and recovery of elemental selenium in a multi-stage bioreactor process with redox potential feedback control

Su Yan; Ka Yu Cheng; Maneesha P Ginige; Christina Morris; Xiao Deng; Jian Li; Shaokun Song; Guanyu Zheng; Lixiang Zhou; Anna H Kaksonen

doi:10.1016/j.jhazmat.2021.127539

Sequential removal of selenate, nitrate and sulfate and recovery of elemental selenium in a multi-stage bioreactor process with redox potential feedback control

J Hazard Mater. 2022 Feb 15;424(Pt C):127539. doi: 10.1016/j.jhazmat.2021.127539. Epub 2021 Oct 19.

Authors

Su Yan¹, Ka Yu Cheng², Maneesha P Ginige³, Christina Morris³, Xiao Deng⁴, Jian Li⁵, Shaokun Song³, Guanyu Zheng⁶, Lixiang Zhou⁶, Anna H Kaksonen⁷

Affiliations

¹ CSIRO Land and Water, 147 Underwood Avenue, Floreat, WA 6014, Australia; Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; College of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China.
² CSIRO Land and Water, 147 Underwood Avenue, Floreat, WA 6014, Australia; School of Engineering and Information Technology, Murdoch University, Perth, WA 6150, Australia.
³ CSIRO Land and Water, 147 Underwood Avenue, Floreat, WA 6014, Australia.
⁴ CSIRO Land and Water, 147 Underwood Avenue, Floreat, WA 6014, Australia; International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
⁵ CSIRO Mineral Resources, Australian Resources and Research Centre, Kensington, WA 6151, Australia.
⁶ Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
⁷ CSIRO Land and Water, 147 Underwood Avenue, Floreat, WA 6014, Australia; School of Biomedical Sciences, University of Western Australia, 35 Stirling Highway, Nedlands, WA 6009, Australia. Electronic address: anna.kaksonen@csiro.au.

PMID: 34800843
DOI: 10.1016/j.jhazmat.2021.127539

Abstract

Bioreduction can facilitate oxyanions removal from wastewater. However, simultaneously removing selenate, nitrate and sulfate and recovering high-purity elemental selenium (Se⁰) from wastewater by a single system is difficult and may lead to carcinogenic selenium monosulfide (SeS) formation. To solve this issue, a two-stage biological fluidized bed (FBR) process with ethanol dosing based on oxidation-reduction potential (ORP) feedback control was developed in this study. FBR1 performance was first evaluated at various ORP setpoints (between -520 and -360 mV vs. Ag/AgCl) and elevated sulfate concentration. Subsequently, ethanol-fed FBR2 was used to reduce sulfate from FBR1 effluent, followed by an aerated sulfide oxidation reactor (SOR). At - 520 mV≤ ORPs≤ -480 mV, FBR1 removed 100 ± 0.1% nitrate and 99.7 ± 0.3% selenate without sulfate reduction. At ORPs ≥ -440 mV, selenate reduction was incomplete, whereas nitrate removal remained stable. Se⁰ recovery efficiency from FBR1 effluent was 37.5% with 71% Se purity. FBR2 converted 86% of the remaining sulfate in FBR1 effluent to hydrogen sulfide, but the over-oxidation of dissolved sulfide in SOR decreased the overall sulfate removal efficiency to ~46.3%. Overall, the two-stage FBR process with ORP feedback dosing of ethanol was effective for sequentially removing selenate, nitrate and sulfate and recovering Se⁰ from wastewater.

Keywords: Bioreactor; Electron donor; Oxidation-reduction potential; Oxyanion; Wastewater treatment.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bioreactors
Feedback
Nitrates*
Oxidation-Reduction
Selenic Acid
Selenium*
Sulfates

Substances

Nitrates
Sulfates
Selenium
Selenic Acid