Sludge-derived iron-carbon material enhancing the removal of refractory organics in landfill leachate: Characteristics optimization, removal mechanism, and molecular-level investigation

Xinyue Chen; Sha Liang; Shuangyi Tao; Wenbo Yu; Shushan Yuan; Sifeng Jian; Nianhong Wan; Yuwei Zhu; Shijie Bian; Yuan Liu; Liang Huang; Huabo Duan; Mukesh Kumar Awasthi; Jiakuan Yang

doi:10.1016/j.scitotenv.2023.166883

Sludge-derived iron-carbon material enhancing the removal of refractory organics in landfill leachate: Characteristics optimization, removal mechanism, and molecular-level investigation

Sci Total Environ. 2023 Dec 15:904:166883. doi: 10.1016/j.scitotenv.2023.166883. Epub 2023 Sep 9.

Authors

Xinyue Chen¹, Sha Liang², Shuangyi Tao¹, Wenbo Yu³, Shushan Yuan², Sifeng Jian⁴, Nianhong Wan⁴, Yuwei Zhu¹, Shijie Bian¹, Yuan Liu¹, Liang Huang², Huabo Duan², Mukesh Kumar Awasthi⁵, Jiakuan Yang²

Affiliations

¹ School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
² School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China.
³ School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycle Technology, Wuhan, Hubei 430074, China; Hubei Provincial Research Center of Water Quality Safety and Water Pollution Control Engineering Technology, Wuhan, Hubei 430074, China. Electronic address: yuwenbo@hust.edu.cn.
⁴ Central & Southern China Municipal Engineering Design and Research Institute Co., Ltd., Wuhan, Hubei 430010, China.
⁵ College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.

PMID: 37690764
DOI: 10.1016/j.scitotenv.2023.166883

Abstract

Mature landfill leachate is a refractory organic wastewater, and needs physical and chemical pretreatments contemporaneously, e.g. iron-carbon micro-electrolysis (IC-ME). In this study, a novel iron-carbon (Fe-C) material was synthesized from waste activated sludge to be utilized in IC-ME for landfill leachate treatment. The pyrolysis temperature, mass ratio of iron to carbon, and solid-liquid ratio in leachate treatment were optimized as 900 °C with 1.59 and 34.7 g/L. Under these optimal conditions, the chemical oxygen demand (COD) removal efficiency reached 79.44 %, which was 2.6 times higher than that of commercial Fe-C material (30.1%). This excellent COD removal performance was indicated to a better mesoporous structure, and uniform distribution of zero-valent iron in novel Fe-C material derived from sludge. The contribution order of COD removal in IC-ME treatment for landfill leachate was proven as coagulation, adsorption, and redox effects by a contrast experiment. The removal of COD includes synthetic organic compounds, e.g. carcinogens, pharmaceuticals and personal care products. The contents of CHO, CHON, and CHOS compounds of dissolved organic matter (DOM) in the leachate were decreased, and both the molecular weight and unsaturation of lipids, lignin, and tannic acids concentration were also reduced. Some newly generated small molecular DOM in the treated leachate further confirmed the existence of the redox effect to degrade DOM in leachate. The total cost of sludge-derived Fe-C material was only USD$ 152.8/t, which could save 76% of total compared with that of commercial Fe-C materials. This study expands the prominent source of Fe-C materials with excellent performance, and deepens the understanding of its application for leachate treatment.

Keywords: Dissolved organic matter; Iron-carbon micro-electrolysis (IC-ME); Landfill leachate; Sludge derived iron-carbon material; Waste activated sludge.