Compact point-of-use treatment and repurposing of domestic laundry greywater through electrocoagulation with finned electrodes

Abstract

Domestic laundry wastewater (DLW), a significant component of urban greywater, remains an underutilized resource for non-potable reuse due to its variable composition and decentralized generation. This study introduces an Extended Fin Electrochemical System (EFECS) designed to enable compact, energy-efficient, and scalable treatment of DLW at the point of use. The novel extended fin aluminum electrode design greatly increases the electrode surface area without enlarging the reactor size, leading to enhanced current dissipation and more efficient pollutant removal than traditional electrochemical systems. The EFECS was systematically evaluated under varying operational conditions, including electrode surface area, applied voltage, and recirculation flow rate. Under optimal conditions (14 V, 20 min), the system achieved 85 % chemical oxygen demand (COD) reduction, 90 % LAS removal, and 95 % turbidity reduction, demonstrating superior kinetics compared to conventional electrocoagulation (EC) systems. The treatment process was governed by electrochemical kinetics, with applied voltage playing a dominant role over mass transport limitations. The system exhibited a competitive energy consumption of 5 kWh/m³ and operating cost of ∼5 Rs/m³ (∼0.06 USD/m³ or ∼0.055 EUR/m³),ss validating its potential for affordable decentralized wastewater reuse. This research highlights the feasibility of integrating EFECS within household appliances for on-site greywater treatment, contributing to sustainable urban water management. Future work will focus on long-term electrode performance and coupling with renewable energy systems to further enhance sustainability.