Enhancement of Mn2+, Fe2+ and NH4+-N removal by biochar synergistic strains combined with activated sludge in real wastewater treatment

Shuman Deng; Qiang An; Jiali Song; Yichen Yang; Zhiruo Huang; Shuyun Feng; Chuanzhu Tang; Bin Zhao

doi:10.1016/j.chemosphere.2024.142271

Enhancement of Mn²⁺, Fe²⁺ and NH₄⁺-N removal by biochar synergistic strains combined with activated sludge in real wastewater treatment

Chemosphere. 2024 May 9:359:142271. doi: 10.1016/j.chemosphere.2024.142271. Online ahead of print.

Authors

Shuman Deng¹, Qiang An², Jiali Song³, Yichen Yang⁴, Zhiruo Huang⁵, Shuyun Feng⁶, Chuanzhu Tang⁷, Bin Zhao⁸

Affiliations

¹ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China. Electronic address: dengshuman@cqu.edu.cn.
² College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China; The Key Laboratory of Eco-Environment in Three Gorges Reservoir Region, Chongqing University, Chongqing, 400045, PR China. Electronic address: anqiang@cqu.edu.cn.
³ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China. Electronic address: songjiali@stu.cqu.edu.cn.
⁴ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China. Electronic address: yichenyang@stu.cqu.edu.cn.
⁵ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China. Electronic address: huangzhiruo@stu.cqu.edu.cn.
⁶ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China. Electronic address: fengshuyun@stu.cqu.edu.cn.
⁷ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China. Electronic address: Tangchuanzhu@stu.cqu.edu.cn.
⁸ College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China; The Key Laboratory of Eco-Environment in Three Gorges Reservoir Region, Chongqing University, Chongqing, 400045, PR China. Electronic address: binzhao11@cqu.edu.cn.

PMID: 38734248
DOI: 10.1016/j.chemosphere.2024.142271

Abstract

Acinetobacter sp. AL-6 combining with biochar was adapted in activated sludge (AS & co-system) to decontaminate Mn²⁺, Fe²⁺ and NH₄⁺-N, and treat activated sludge (AS) for its activity and settling performance improvement. Specifically, the co-system promoted the growth of bacteria in the activated sludge, thus increasing its ability to nitrify and adsorb Mn²⁺ and Fe²⁺, resulting in the removal of high concentrations of NH₄⁺-N, Mn²⁺, Fe²⁺ and COD in the reactor by 100%, 100%, 100%, and 96.8%, respectively. And the pH of wastewater was increased from 4 to 8.5 by co-system also facilitated the precipitation of Mn²⁺ and Fe²⁺. The MLVSS/MLSS ratio increased from 0.64 to 0.95 and SVI₃₀ decreased from 92.54 to 1.54 after the addition of co-system, which indicated that biochar helped to improve the activity and settling performance of activated sludge and prevented it from being damaged by the compound Mn²⁺ and Fe²⁺. In addition, biochar promoted the increase of the tyrosine-like protein substance and humic acid-like organic matter in the sludge EPS, thus enhanced the ability of sludge to adsorb Mn²⁺ and Fe²⁺. Concretely, compared with AS group, the proteins content and polysaccharides content of the AS & co-system group were increased by 13.14 times and 6.30 times respectively. Further, microbial diversity analysis showed that more resistant bacteria and dominant bacteria Acinetobacter sp. AL-6 in sludge enhanced the nitrification and adsorption of manganese and iron under the promotion of biochar. Pre-eminently, the more effective AS & co-system were applied to the removal of actual electrolytic manganese slag leachate taken from the contaminated site, and the removal of NH₄⁺-N, Mn²⁺, Fe²⁺ and COD remained high at 100%, 100%, 71.82% and 94.72%, respectively, revealing advanced value for high engineering applications of AS & co-system.

Keywords: Activated sludge; Biochar; Complex Mn(2+) and Fe(2+) contamination; EPS; Microbial diversity.