To assess and to optimize the treatment of effluents containing poly(vinyl alcohol) (PVA) from a poly(vinyl chloride) (PVC) production site, two aerobic membrane bioreactors (MBR) were run in parallel. PVA and total organics degradation, pH, temperature, oxygen consumption, organic loading rate, hydraulic retention time, and macro- and micronutrients contents were measured and optimized. Total removal of PVA, total nitrification, > 90% chemical oxygen demand (COD) removal, and >95% biological oxygen demand (BOD5) reduction were achieved from a mixed culture of microorganisms after an adequate adaptation period. In addition, different bacteria cultures were assessed aid analyzed in order to study PVA biodegradation: gamma-proteobacteria and alpha-proteobacteria were the main groups of PVA-degrading bacteria. Membranes showed a good performance during the trials. Furthermore, permeability was completely recovered by chemical cleaning. After the assessed MBR treatment, the effluent fulfills appropriate water quality requirements for its post-treatment in a desalination unit in order to be reused within the PVC production processes.