Iron sulphides mediated autotrophic denitrification: An emerging bioprocess for nitrate pollution mitigation and sustainable wastewater treatment

Yuansheng Hu; Guangxue Wu; Ruihua Li; Liwen Xiao; Xinmin Zhan

doi:10.1016/j.watres.2020.115914

Iron sulphides mediated autotrophic denitrification: An emerging bioprocess for nitrate pollution mitigation and sustainable wastewater treatment

Water Res. 2020 Jul 15:179:115914. doi: 10.1016/j.watres.2020.115914. Epub 2020 May 6.

Authors

Yuansheng Hu¹, Guangxue Wu², Ruihua Li³, Liwen Xiao⁴, Xinmin Zhan⁵

Affiliations

¹ Civil Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland; Ryan Institute, National University of Ireland, Galway, Ireland.
² Institute of Environmental Engineering and Management, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China.
³ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Avenue, Nanjing, 210023, China.
⁴ Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland.
⁵ Civil Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland; Ryan Institute, National University of Ireland, Galway, Ireland; MaREI Centre for Marine and Renewable Energy, Ireland. Electronic address: xinmin.zhan@nuigalway.ie.

PMID: 32413614
DOI: 10.1016/j.watres.2020.115914

Abstract

Iron sulphides, mainly in the form of mackinawite (FeS), pyrrhotite (Fe_1-xS, x = 0-0.125) and pyrite (FeS₂), are the most abundant sulphide minerals and can be oxidized under anoxic and circumneutral pH conditions by chemoautotrophic denitrifying bacteria to reduce nitrate to N₂. Iron sulphides mediated autotrophic denitrification (ISAD) represents an important natural attenuation process of nitrate pollution and plays a pivotal role in linking nitrogen, sulphur and iron cycles in a variety of anoxic environments. Recently, it has emerged as a promising bioprocess for nutrient removal from various organic-deficient water and wastewater, due to its specific advantages including high denitrification capacity, simultaneous nitrogen and phosphorus removal, self-buffering properties, and fewer by-products generation (sulphate, waste sludge, N₂O, NH₄⁺, etc.). This paper provides a critical overview of fundamental and engineering aspects of ISAD, including the theoretical knowledge (biochemistry, and microbial diversity), its natural occurrence and engineering applications. Its potential and limitations are elucidated by summarizing the key influencing factors including availability of iron sulphides, low denitrification rates, sulphate emission and leaching heavy metals. This review also put forward two key questions in the mechanism of anoxic iron sulphides oxidation, i.e. dissolution of iron sulphides and direct substrates for denitrifiers. Finally, its prospects for future sustainable wastewater treatment are highlighted. An iron sulphides-based biotechnology towards next-generation wastewater treatment (NEO-GREEN) is proposed, which can potentially harness bioenergy in wastewater, incorporate resources (P and Fe) recovery, achieve simultaneous nutrient and emerging contaminants removal, and minimize waste sludge production.

Keywords: Autotrophic denitrification; Groundwater remediation; Iron sulphides; Phosphorus recovery; Sludge minimization; Sulphur-oxidizing denitrification (SOD).

Publication types

Review

MeSH terms

Autotrophic Processes
Bioreactors
Denitrification*
Ferrous Compounds
Iron
Nitrates
Nitrogen
Sulfides
Waste Disposal, Fluid
Wastewater*

Substances

Ferrous Compounds
Nitrates
Sulfides
Waste Water
Iron
Nitrogen
ferrous sulfide