Chemicals/water recoveries from milk and butter factories under a bipolar-membrane electrodialysis system-batch reverse osmosis system structure

The growing volume of wastewater produced by milk and butter factories makes it increasingly important to integrate effective water-recovery technologies into treatment systems. Bipolar-membrane electrodialysis (BMED)-systems have recently gained attention for their ability to treat wastewater efficiently while enabling water and chemical recovery. This study presents the technical and economic assessment of a hybrid treatment system combining batch reverse osmosis (BROS) with a BMED-system. The study is based on mechanistic process modelling and techno-economic analysis rather than experimental measurements. The core goal of this hybrid configuration is to recover both water and valuable chemicals from dairy-processing effluents. Unlike previously reported RO– BMED-systems, the proposed BROS– BMED-system uses a batch RO step to pre-concentrate wastewater before it enters the BMED-system. Raising the feed concentration strengthens the driving force for ion migration, which in turn improves both energy efficiency and cost performance. Through this approach, the system can simultaneously produce reusable water along with high-purity acids and bases, while reducing energy consumption due to the more concentrated feed entering the BMED-system. In the modeling approach, the BROS operates as a batch unit that gradually increases the feed concentration until reaching an FCL of 6.3, representative of typical dairy wastewater. The BMED-system stage is modeled under steady-state conditions at an optimized current density of 296 A m −2 using commercially available ion-exchange and bipolar membranes. A comprehensive comparison between integrated and standalone BMED-systems highlights major performance indicators such as water-recovery rate, acid/base purity, specific energy demand, and overall production cost. The model findings suggest that the optimized hybrid design has the potential to improve economic viability, projecting a reduction in total production costs of approximately 25.5% compared with a non-integrated setup. The simulation indicates a promising operating scenario at an FCL of 6.3 and a current density of 296 A m −2 , resulting in a unit cost of 12.93 for the overall treatment process.