Iron-retrofitted anaerobic baffled reactor system for rural wastewater treatment: Stable performance of nutrients removal with phosphorus recovery and minimal sludge production

Bioresour Technol. 2024 Sep:408:131179. doi: 10.1016/j.biortech.2024.131179. Epub 2024 Jul 30.

Authors

Ruoning Zheng¹, Xiaohui Cheng², Xiaozhong Gao³, Changyong Zhang⁴, Xiang Cheng⁵, T David Waite⁶

Affiliations

¹ Beijing Key Laboratory for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China. Electronic address: kiwicoooo@bjfu.edu.cn.
² Beijing Key Laboratory for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China. Electronic address: chengxiaohui@bjfu.edu.cn.
³ Beijing Key Laboratory for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China. Electronic address: gaoxz1003@bjfu.edu.cn.
⁴ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China. Electronic address: changyongzhang@ustc.edu.cn.
⁵ Beijing Key Laboratory for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China. Electronic address: xcheng@bjfu.edu.cn.
⁶ Water Research Center, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: d.waite@unsw.edu.au.

PMID: 39084532
DOI: 10.1016/j.biortech.2024.131179

Abstract

An iron-retrofitted anaerobic baffled reactor (ABR) system was developed for the effective treatment of rural wastewater with reduced maintenance demand and aeration costs. Average removal efficiencies of chemical oxygen demand, total nitrogen and total phosphorus of 99.4%, 62.7% and 92.6% were achieved respectively, when the ABR system was operating at steady state. With effective bioreduction of Fe^III in the anaerobic chambers, phosphorus was immobilized in the sludge as vivianite, the sole phosphorus-carrying mineral. The Fe^III in the recirculated sludge induced Feammox in the ABR reactor, contributing 14.8% to total nitrogen removal. Biophase separation and enrichment of microorganisms associated with iron and nitrogen transformations were observed in the system after Fe dosing, which enhanced the removal of pollutants. The coupling of Feammox and vivianite crystallization to remove nitrogen and phosphorus in an iron-retrofitted ABR would appear to be a promising technology for rural wastewater treatment.

Keywords: Anaerobic treatment; Feammox; Iron transformation; Vivianite crystallization.

MeSH terms

Anaerobiosis
Biological Oxygen Demand Analysis
Bioreactors*
Iron* / chemistry
Nitrogen
Nutrients
Phosphorus*
Rural Population
Sewage*
Waste Disposal, Fluid / methods
Wastewater* / chemistry
Water Purification* / methods

Substances

Phosphorus
Sewage
Iron
Wastewater
Nitrogen