Water scarcity is closely related to the sharp increase in the world’s population and industrial production, raising water demand and wastewater discharge. The textile industry is a water-intensive consumer, resulting in intensive wastewater generation. Textile wastewater reuse is only possible through technologies such as reverse osmosis, which presents challenges like the final disposal of the retentate and the membrane fouling. This study aims to provide a solution to these challenges through the electrooxidation (EO) of reverse osmosis retentate (ROR) with a Ti/IrO2-RuO2 anode, which can generate reactive chlorine species from chloride, enabling its reuse as an antifouling agent. Different ROR samples were used and the influence of applied current intensity (0.5–1.0 A) and sample volume (5.0–15.0 L) was evaluated. The results showed that, at the experimental conditions studied, the rate of chloride oxidation was only dependent on the applied electric charge, being unaffected by the ROR characteristics, sample volume, or applied current intensity. Also, the higher the initial amount of chloride, the lower the specific energy consumption (kWh m−3) and the process efficiency in converting chloride to hypochlorite. Alongside hypochlorite generation, EO promoted organic load and color removal, being the final pH (8.5–9.0) acceptable for reuse in membrane processes. The treated ROR was successfully used as an antifouling agent in a membrane treatment plant, showing that the proposed treatment is an effective strategy to improve sustainability in the textile industry through a circular economy approach.