Gaining comprehensive insight into the effect of electrocoagulation integrated in a membrane bioreactor on the detergent manufacturing plant wastewater treatment and membrane fouling

This study evaluated the integration of electrocoagulation into a lab-scale membrane bioreactor (EC-MBR) for treating wastewater from a detergent manufacturing plant. The EC-MBR system achieved a higher chemical oxygen demand (COD) and anionic surfactant removal efficiencies of 95.1% and 99.7% compared to 93.3% and 98.7% in the MBR system, respectively. Sludge volume index and mixed liquor supernatant turbidity revealed superior sludge settling and flocculation ability, respectively, in the EC-MBR system compared to the MBR system. Membrane fouling was less severe in the EC-MBR system, linked to reduced concentrations of soluble microbial products and loosely bond extracellular polymeric substances, especially their protein to carbohydrate ratio, as well as increased particle size in the mixed liquor. Fourier transform infrared spectroscopy (FTIR) analysis indicated that the membrane cake layer was mainly composed of protein and carbohydrate. Scanning electron microscopy (SEM) revealed microbial clusters in the MBR system composed of rod- and oval-shaped bacteria, while the EC-MBR system primarily showed spherical microbial structures. The EC-MBR system demonstrated low energy consumption (1.75 kWh m⁻³) and operating costs ($0.55 m⁻³), highlighting its efficiency and cost-effectiveness for sustainable wastewater management.