Maximizing Water Recycling in Automotive Manufacturing in a Water-Stressed Region

General Motors (GM) owns and operates a large manufacturing complex in Silao, Guanajuato Mexico. GM is embarking on a comprehensive water recycling program to maximize water reuse for manufacturing processes, and to augment the current source of water for the Site, which is local fresh groundwater wells. The Site currently recycles approximately 35% of the biologically-treated and tertiary-filtered wastewater effluent for use in cooling towers, irrigation, and to toilet rooms. The conceptual treatment train for a new water reuse treatment system includes a membrane bioreactor (MBR) and three-stage reverse osmosis (RO) in Phase I, to recycle approximately 80% of the site’s wastewater. A future phase of the project would include on-site treatment of the brine from the RO process, recovering even more water through application of zero-liquid discharge technology (evaporator/crystallizer combination with mechanical vapor recompression), achieving over 95% recovery.