Performance Evaluation of Two Low Current Densities in the Electrocoagulation Process for the Real Dairy Wastewater Treatment

کد مقاله : 1706-IWWA

نویسندگان

فروغ عرب * ندارم

چکیده مقاله

The dairy industry generates substantial volumes of high-strength wastewater characterized by elevated chemical oxygen demand (COD), oil and grease (O&G), and turbidity, posing significant environmental risks if discharged without adequate treatment. This study evaluates the performance of an electrocoagulation (EC) system equipped with iron electrodes for the treatment of real dairy wastewater under two low current densities (1 and 2 mA/cm²). The reactor, operating in batch mode with a 10 min ON/30 min OFF cycle, achieved a COD removal efficiency of 82.71% at J=1 mA/cm², which declined to 76.30% at J=2 mA/cm². Similarly, O&G removal efficiency decreased from 96.27% to 94.05% as current density increased. Turbidity remained nearly unchanged under both conditions (43.1 NTU at J=1 mA/cm² and 42.3 NTU at J=2 mA/cm²), indicating that colloidal removal reached saturation at the lower current density. Anodic dissolution increased from approximately 4 g at J=1 mA/cm² to 9 g at J=2 mA/cm², consistent with Faraday's law, while the residual Fe²⁺ concentration in the effluent increased from 6 to 8 mg/L. The decline in COD and O&G removal at higher current density is attributed to the overdosing phenomenon, in which excessive coagulant release induces charge reversal and restabilization of colloidal and emulsified particles. The results demonstrate that increasing current density beyond an optimal threshold does not enhance treatment efficiency and may even impair performance, highlighting the importance of optimizing current density for techno-economically viable EC operation.

کلیدواژه ها

Electrocoagulation, Dairy wastewater, Current density, COD removal, Overdosing phenomenon, Iron electrodes

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