Electrodialysis parameter optimisation following aeration strategy of anaerobic membrane bioreactor effluent to enhance water quality and nutrient recovery

Considering scaling and membrane adsorption limiting phosphorus recovery in previous studies, this work proposes integrating Anaerobic Membrane Bioreactor effluent aeration with Electrodialysis, improving treatment performance. The objective is to produce two streams: a nutrient-rich stream suitable for recovery, and a diluted stream meeting discharge regulations. Short-term experiments were conducted under varying currents and applied voltages, aiming to determine the best operating conditions. Subsequently, long-term experiments were conducted to assess operational stability, and overall system performance. Results indicated that 0.1 A and 7.5 V were the best values for galvanostatic and potentiostatic mode. Moreover, long-term tests demonstrated that electrodialysis effectively concentrated nitrogen and phosphorus, enabling their recovery, while reducing pollutant load in the effluent. Specifically, in the concentrate up to 952.35 mg NH 4 -N/L and 72.44 mg PO 4 -P/L at 0.1 A and 856.04 mg NH 4 -N/L and 70.05 mg PO 4 -P/L at 7.5 V resulted. Diluted stream meets regulations for nitrogen, obtaining 4.7 ± 0.9 and 3.6 ± 0.5 mg/L at galvanostatic and potentiostatic mode. These findings highlight electrodialysis as a promising and sustainable strategy for nutrient recovery and effluent management in advanced wastewater treatment, although strategies such as multi-stage ED, increasing membrane area, anti-scaling coatings or cleaning protocols are necessary to improve phosphorus removal and ensure compliance with regulatory standards. • ED concentrated nutrients from AnMBR effluent, achieving 75 % and 60 % P recovery. • Current and voltage adjustment via short-term tests enhanced process performance. • Long-term operation confirmed process stability with an energy demand of 0.5kWh/m 3 . • ED removed 90 % N and 80 % P significantly improving effluent quality. • ED + AnMBR integration enhances the sustainability of decentralised WW treatment.