Avaliação da ozonização como processo oxidativo avançado na remoção de manganês em efluente de mineração: estudo de caso

Abstract

The mining industry faces significant environmental challenges related to water management of effluents, especially due to the presence of dissolved metals that can persist even after conventional treatments, posing severe risks to ecosystems and public health. Among these contaminants, manganese stands out due to the difficulty of removal by chemical precipitation under near-neutral conditions, often proving insufficient to meet stringent discharge standards or generating large volumes of toxic waste. In this context, this work analyzes the application of ozonation, classified as an Advanced Oxidation Process (AOP), as a complementary technology in the treatment of mining effluents. The methodology was based on a critical literature review and the analysis of a pilot-scale case study, where ozonation was applied after conventional physicochemical treatment (High-Density Sludge (HDS) system) for the removal of manganese from copper mining effluents. The literature review and the analyzed case study demonstrate that ozonation can act synergistically with traditional physicochemical systems, such as the high-density sludge (HDS) process, functioning as a polishing step for the final adaptation of the effluent to environmental limits. Furthermore, the lower dependence on chemical reagents and the possibility of operation at near-neutral pH represent significant operational advantages. However, the viability of application on an industrial scale depends on factors such as electricity costs, gas-liquid transfer efficiency, and specific effluent characteristics, indicating that the technology's performance is strongly dependent on the operational context. Thus, although ozonation does not entirely replace conventional treatments, it is consolidating itself as a strategic alternative to increase the overall efficiency of the treatment system, reduce environmental impacts, and contribute to water sustainability in mining. As an academic contribution, this work integrates the fundamentals of oxidative chemistry with the environmental problem of metal removal in mining effluents, highlighting the relationship between reaction mechanisms, operational performance, and legal requirements, offering a theoretical basis for future experimental investigations and real-scale applications.