Characterization of dissolved organic matter during the O3-based advanced oxidation of mature landfill leachate with and without biological pre-treatment and operating cost analysis

Hualiang Feng; Wenlong Mao; Yenan Li; Xiaojun Wang; Shaohua Chen

doi:10.1016/j.chemosphere.2021.129810

Characterization of dissolved organic matter during the O₃-based advanced oxidation of mature landfill leachate with and without biological pre-treatment and operating cost analysis

Chemosphere. 2021 May:271:129810. doi: 10.1016/j.chemosphere.2021.129810. Epub 2021 Jan 30.

Authors

Hualiang Feng¹, Wenlong Mao², Yenan Li³, Xiaojun Wang⁴, Shaohua Chen⁵

Affiliations

¹ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: hlfeng@iue.ac.cn.
² CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. Electronic address: wlmao@iue.ac.cn.
³ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
⁴ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. Electronic address: xjwang@iue.ac.cn.
⁵ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. Electronic address: shchen@iue.ac.cn.

PMID: 33736207
DOI: 10.1016/j.chemosphere.2021.129810

Abstract

In this study, the organic matter in an O₃-based advanced oxidation process (AOP) for treating raw leachate (RL) and bio-treated leachate (BTL) was characterized. The optimal conditions for COD removal in RL and BTL treatment were as follows: initial pH of 6.0 and H₂O₂ dosage of 9 mL 30% H₂O₂ L^-1 leachate, and initial pH of 12 without H₂O₂ addition, respectively. H₂O₂ addition had little influence on COD removal in the BTL treatment as sufficient hydroxyl radicals may not be produced at extremely high pH levels. The differences in the alkalinity between RL and BTL caused differences in the optimum pH of the AOPs. Overall, the initial pH more affected COD removal than the H₂O₂ dosage. O₃-based AOP converted organics with high molecular weight fractions into low ones. Meanwhile, it preferentially degraded hydrophobic substances over hydrophilic substances. The organic matter in the BTL contained more refractory and hydrophobic fractions; therefore, higher COD removal was achieved in the treatment of RL. The organics in the treatment of RL and BTL were identified by excitation-emission matrix spectroscopy combined with parallel factor analysis, and their degradation decreased in the following order: terrestrial humic-like > microbial humic-like > combination of tryptophan and humic-like components. O₃-based AOP significantly enhanced biodegradability. According to the economic analysis results, as an intermediate treatment, O₃-based AOP is a cost-effective strategy of ensuring that leachate effluent meets the discharge standards, with the lowest operating cost of $4.62 m^-3. This study provides a reference for the application of O₃-based AOP in full-scale landfill leachate treatment.

Keywords: Condition optimization; EEM-PARAFAC; Economic evaluation; Mature landfill leachate; Molecular size distribution; O(3)-based AOPs.

MeSH terms

Costs and Cost Analysis
Hydrogen Peroxide
Hydroxyl Radical
Oxidation-Reduction
Water Pollutants, Chemical* / analysis

Substances

Water Pollutants, Chemical
Hydroxyl Radical
Hydrogen Peroxide