The transition from laboratory scale production to industrial scale implementation is a critical step in introducing innovative technologies into the industry. Pilot-scale studies play a pivotal role in ensuring a smooth transition with minimal risks. This study investigates the scalability of a pilot-scale submerged membrane bioreactor (MBR) to produce volatile fatty acids (VFAs) as a sustainable alternative feed ingredient for ruminants. Building upon previous laboratory-scale research, this study aims to validate the scalability and replicability of the technology, ensuring that the results obtained at a smaller scale can be consistently achieved at a larger scale. Through the acidogenic fermentation of potato protein liquor (PPL) and apple pomace (AP) inoculated with rumen microorganisms, VFAs have been produced, and recovered over 105 days. Strategic adjustments to the organic loading rate (OLR, 2 gVS/L.day) achieved high and stable total VFAs concentration (above 10 g/L) with average VFAs yield of 0.47 gVFAs/gVSadded by effectively inhibiting methanogenesis. The favorable characteristics of the VFAs effluent, including its pH, VFAs distribution (high acetic and caproic acids), and ammonium content (around 400 mg/L), suggest its potential as a sustainable feed ingredient for ruminants. Further research is necessary to explore the precise effects and optimal utilization of VFAs as a feed supplement, but this study presents a promising step towards sustainable VFAs production and its application in the livestock sector.