Le Thi Quynh Trang, Trieu Quy Huy
Industrial laundry wastewater contains surfactants, suspended solids, and poorly biodegradable organics that challenge conventional biological treatment. Electrocoagulation (EC) offers an alternative by generating coagulants in situ without external chemicals, yet most studies still focus on batch systems, while continuous-flow reactor design and energy performance remain insufficiently explored. This study develops and optimizes a continuous-flow EC reactor for treating industrial laundry wastewater, focusing on hydrodynamics and electrode configuration. Three reactors with identical effective volumes but different flow geometries straight, serpentine and baffled channels were constructed and evaluated using residence time distribution (RTD) tests and CFD simulations to analyze flow uniformity and dead zones. Serpentine and baffled configurations significantly reduced short-circuiting and stagnant regions, improving hydraulic efficiency. Consequently, COD and turbidity removals exceeded 80% and 90%, respectively, while specific energy consumption decreased to below 1.5 kWh/m³. Optimizing electrode spacing and applying periodic polarity reversal further mitigated electrode passivation and enhanced operational stability. The study provides practical mechanical design guidance to support real-world implementation and scale-up of continuous-flow EC systems for industrial laundry wastewater treatment. The novelty of this work lies in the integrated optimization of reactor hydrodynamics (straight, serpentine channel, baffled channel) with RTD-CFD analysis and specific energy consumption evaluation for continuous-flow electrocoagulation of industrial laundry wastewater. Integration of reactor hydrodynamics (straight, serpentine channel, baffled channel), CFD/RTD dead-zone analysis, and electrocoagulation performance-energy evaluation for continuous-flow treatment of industrial laundry wastewater.