Remediation of real, freshly collected dairy wastewater via electrocoagulation–electroflotation under batch and continuous flow conditions

Abstract BACKGROUND Dairy wastewater (DWW) is characterized by high organic and suspended solid loads and its treatment remains a challenge for sustainable dairy industry operation. This study evaluates electrocoagulation‐electroflotation (EC/EF) with aluminum electrodes for treating real DWW under both batch and continuous‐flow conditions. RESULTS Experiments were performed in situ at the industry using fresh wastewater with variable initial pH (5.0–7.0), chemical oxygen demand (COD 0 :10800–3200 mg/L), and total suspended solids (TSS: 880–2030 mg/L). Batch experiments at current intensities of 0.15, 0.25, 0.5, and 1.0 A showed that 0.25 A (89.2 A/m 2 ) was particularly effective, achieving 79.75% COD and 95.76% TSS removal within 10 min at 10800 mg/L COD 0 and natural pH 5.33, with low energy consumption (0.14 kWh/m 3 ) and aluminum dissolution (27.96 g/m 3 ). For adjusted initial pH values of 5, 6, and 7 and COD 0 = 3200 mg/L, maximum COD and TSS removal occurred at pH 5, likely due to its proximity to the isoelectric point (~pH 3.7). Similarly, for COD 0 = 6200 mg/L, treatment at natural pH 6 yielded 79.22% COD and 90.37% TSS removal. At 4500 mg/L COD 0 , maintaining natural pH 6.7 reduced treatment time from 30 to 20 min while sustaining COD removal (~63%), although TSS removal dropped by ~36%. Continuous‐flow experiments at COD 0 = 6500 mg/L achieved steady‐state removal of ~72% COD of and 98% TSS at pH 5 with a 15‐min hydraulic retention time. CONCLUSION Overall, EC/EF proved technically viable, energy‐efficient, and effective for high‐strength DWW treatment, supporting its use as a pretreatment step in decentralized or industrial wastewater treatment systems. © 2026 Society of Chemical Industry (SCI).