## 1 Introduction  
The generation of municipal solid waste (MSW) has increased as a result of continuous improvements in living standards and the expansion of the global economy [1, 2]. MSW management has very different characteristics in developed and developing countries. European countries have focused their attention on prevention and recycling rather than final disposal. The European Commission has set a target of recycling 65% of the MSW generated in 2023, thereby reducing MSW deposited in landfills. In 2014, some countries recycled at least 50% of their waste, as was the case in the Netherlands, Belgium, Austria, Sweden, and Switzerland. The percentage of MSW deposited in landfills decreased from 49% in 2004 to 34% in 32 member countries of the European Economic Area [3]. A different situation occurs in developing countries, where more than 90% of urban solid waste is burned or deposited in uncontrolled places [4]. The risks to the environment and health are significantly increased by inadequate management of MSW. Based on studies by [PERSON] et al. [5] and [PERSON] et al. [6], landfill operations present a risk of contamination in aquifers, seas, soils, and surface water. Owing to the decomposition of MSW and the filtration of rainwater, landfills produce highly contaminated wastewater known as leachate landfills [7], which will be referred to as leachates in this document. Leachate treatment is a fundamental requirement to prevent possible environmental effects. However, owing to its high degree of compositional and quantitative variability, the leachate treatment is complex [8; 9; 10]. More specifically, stabilized leachates from landfills over ten years old contain refractory or recalcitrant compounds, which further problematize treatment [11]. Low chemical oxygen demand (COD) characterizes stabilized leachates (<5.0 g L\({}^{-1}\)), low biodegradability index (BI) (ratio between biochemical oxygen demand (BODs) and COD) <0.1, and high pH > 7.5 [11; 12; 13; 14]. Leachates typically contain heavy metals such as copper (Cu\({}^{2+}\)), zinc (Zn\({}^{2+}\)), cadmium (Cd\({}^{2+}\)), lead (Pb\({}^{2+}\)), chromium (Cr\({}^{3+}\)), and nickel (Ni\({}^{2+}\)) [15; 16; 17; 18]. For stabilized leachates, these levels remain low due to an increase in pH, which is characteristic of the methane-generating stages of MSW decomposition in landfills, increasing the soil's sorption capacity and immobilizing the metals [15; 19]. The refractory organic fraction of stabilized leachates consists mainly of humic materials, such as humic acids (HA) and fulvic acids (FA), which are highly toxic and complex in composition. Owing to their aromatic structures, humic substances are known for their high molecular weight and low biodegradability [11; 20]. Due to the presence of refractory organic compounds that affect the microbial activity of these systems, conventional biological methods are ineffective for treating the stabilized leachates. Different processing technologies are usually required owing to the complex nature of stabilized leachates [21]. Electrochemical processes have replaced chemical oxidation as the preferred method for the treatment of stabilized leachates and have proven to be a viable alternative [22; 23]. Electro-oxidation (EO) and electro-coagulation (EC) are electrochemical treatment options. Economically viable and employing an ecological strategy, EC has a high capacity for removing pollutants. [PERSON] et al. [24] reported that EC works by producing ions via electricity-mediated electrolysis. Owing to their accessibility, superior ability to remove contaminants, and continuous production of active ions, aluminum (AI) and iron (Fe) are the materials most frequently used as anodes in the EC process [25]. In the case of treatment with EO, it is essential to emphasize that it is a safe and environmentally friendly alternative that is good at what it does, does not generate secondary contamination, and has applications in the treatment of wastewater with recalcitrant organic matter content.