Cada año se vierten millones de metros cúbicos de aguas residuales a los cuerpos de agua, las cuales son tratadas de forma inadecuada, siendo estos procedimientos ineficientes para alcanzar lo requerido por la ley o para uso dentro de los procesos industriales. En estos casos, y debido a la escasez del hídrico, se está recurriendo al uso de los procesos de oxidación avanzada como tratamiento alternativo. Estos procesos se basan en procesos fisicoquímicos capaces de producir cambios profundos en la estructura química de los contaminantes, involucrando la generación y uso de especies transitorias de gran poder oxidante, principalmente el radical hidroxilo, el cual puede ser generado por medios fotoquímicos o por otras formas de energía y posee alta efectividad para la oxidación de materia orgánica. Esta revisión tiene como objetivo realizar un análisis de la influencia de los tratamientos en el proceso de descontaminación.

One of the main problems in Mexico is contamination by leachates that are produced in final waste disposal sites, since they are highly toxic and damage the biota. This research focuses on determining the characteristics of the leachate produced in the uncontrolled final disposal site in the municipality of Tlapacoyan, Veracruz (Mexico). As a result, it was determined that the parameters that cause damage to the biota are total nitrogen (152.759 mg L^-1), mercury (0.006 mg L^-1), cadmium (0.003 mg L^-1), copper (0.052 mg L^-1), chromium (0.0731 mg L^-1), nickel (0.0524 mg L^-1), lead (0.005 mg L^-1) and total coliforms (> 2 400 MPN), as they do not meet at least one of the national and international standards of maximum permissible limits. Likewise, it was determined that the leachate produced at this site is of the mature and poorly biodegradable type (BOD/COD=0.018), so that the typical or bioremediation methods are not recommended for its treatment.

Surface water bodies provide essential ecosystem services, but their quality is increasingly being affected by human activities. In Mexico, information on the impact of leachate generated by open-air municipal landfills on surface water bodies remains limited. The objective of this study was to assess the water quality of the Alseseca River in Tlapacoyan, Veracruz, Mexico, at a point located approximately 200 m from a municipal landfill lacking leachate control infrastructure. The hypothesis was that proximity to the landfill negatively affects water quality by increasing levels of microbiological contaminants and heavy metals. Monitoring was conducted every ten days between January and December 2025, yielding a total of 36 samples. Biological and physicochemical parameters, as well as heavy metals, were analyzed in accordance with current Mexican regulations and the Standard Methods for the Examination of Water and Wastewater. The results showed average concentrations of E. coli exceeding 2 400 MPN 100 mL-¹, surpassing the limits established by NOM-001-SEMARNAT-2021. The physicochemical parameters evaluated remained within national limits, although some values exceeded international reference values. Additionally, arsenic, cadmium, copper, chromium, mercury, nickel, lead, and zinc were detected. The Water Quality Index based on heavy metals classified the water as poor quality. The results suggest a possible influence of landfill leachate on the aquatic ecosystem and highlight the need to strengthen environmental monitoring and management efforts in water bodies near municipal solid waste disposal sites.

Aim: One of the biggest problems of the 21st century is water scarcity and the lack of optimal treatments to solve a need that is increasing due to the contamination of this resource and growing population. The objective of this research is to conduct laboratory-level research on the efficiency of conventional treatments, advanced oxidation processes, and a modified electrocoagulation treatment. Methodology and results: The process known as typical treatment with aluminum sulfate at concentrations of 75, 150, and 225 mg and pH levels of 2, 3, and 4; Fenton reaction at the above concentrations using ferrous sulfate and 0. 22 mL of hydrogen peroxide at the above pH conditions; electrocoagulation with Fenton was performed at a voltage of 17.5 and 19 V, using aluminum electrodes and Fenton reagent conditions similar to the above-mentioned process, except for the medium, where a pH of 8 and 10 is proposed. According to the above experiments, the following results were obtained respectively: Typical treatment with an average removal of 0%, Fenton maximum average removal of 50% at pH 4 and 225 mg of reagent; modified electrocoagulation obtained maximum average removals of 97.6% at pH 8, 19 V, 75 mg of Fenton, and 60 min. Conclusions, Significance, and Impact Study: The addition of Fenton reagent to the electrocoagulation process helps to reduce the reaction time to 30 minutes, according to the literature, making modified electrocoagulation a viable treatment for nickel-contaminated water, in addition to achieving higher removal results than other treatments.