Life Cycle Assessment of Fluoride Removal from Mining Effluents Using Electrocoagulation and Biogenic CO2

Fluoride-containing wastewater poses a significant environmental challenge, especially in the mineral processing sector. This study applies a life cycle assessment (LCA) to evaluate an electrocoagulation-based treatment process, integrating biogas-derived CO2 for pH regulation and cogeneration of electricity, using the Egalitarian perspective, which is the most precautionary that takes into account the longest time frame and impact types that are not yet fully established but for which some indication is available. The LCA considered five subsystems: electrocoagulation, pH adjustment, sedimentation, pumping, and sludge transport, across three operational scenarios. Scenario 1 (S1) employed hydrochloric acid for pH control, Scenario 2 (S2) used biogas exclusively for pH regulation, and Scenario 3 (S3) combined biogas-based pH adjustment with power generation. Results showed an environmental impact ranking of S3 < S1 < S2, with S3 reducing overall impacts from 12.5 Pt to 6.4 Pt compared to S1. The electrocoagulation unit was the dominant contributor to environmental burdens; however, in S3, the pH adjustment subsystem delivered a net environmental benefit through surplus electricity generation. Additionally, sludge reuse as a raw material for brick production, implemented in all scenarios, further mitigated impacts. Human health emerged as the most affected endpoint, driven mainly by toxicity (carcinogenic and non-carcinogenic), climate change potential, marine ecotoxicity, and particulate matter formation. These findings highlight the benefits of integrating biogas utilization and sludge valorization into industrial wastewater management strategies.