The General Motors de Mexico Ramos Arizpe Complex

Proving that more products can be manufactured with less water, and that corporate environmental sustainability can go hand-in-hand with the financial bottom line, the General Motors de Mexico Ramos Arizpe Complex received the 2001 Stockholm Industry Water Award.

The facility enhanced production while at the same time reduced water consumption through reuse of both industrial and sanitary wastewater within production processes. Together with a commitment to continuous improvement, GM’s Ramos Arizpe Complex demonstrated good competence by utilising appropriate technology for differing circumstances. By manufacturing more products with less water, it also demonstrated the win-win opportunity to reduce costs while simultaneously improving the environment – a reflection that successful technical and economic results can be combined with a strong social commitment.

Local Water Scarcity and Corporate Responsibility Drive Innovations
The complex opened in 1980 in Ramos Arizpe (pop. 40,000), an area where the only source of water was a small, semi-confined aquifer with a relatively high salt content (0.2%). The company’s challenge was to secure water for production without depleting the aquifer (which is also the local drinking water source), desalinate the well water supply, and establish a recycling and reuse process for the industrial and sanitary wastewater — all within the framework of an intensive water conservation program.

To help reduce its consumption from the aquifer, the facility employed a variety of physical, chemical and biological wastewater treatment processes to recover and reuse 70% of its industrial wastewater. The selective use of different processes – whether advanced (micro-filtration), simple (solar evaporation ponds), or high tech (membrane filtration) – enabled the facility to effectively tailor its water conservation and recovery program as needed, and to make it as efficient and cost-effective as possible. To convert brine to solid salts and thus facilitate their removal, a recovery system involving micro-filtration, reverse osmosis and solar evaporation ponds was used. This promoted efficient use of well water by increasing the usable amount withdrawn from 67% to 94%.

Through such efforts, GM de Mexico has reduced annual well water withdrawal from 1,470,000 m3/year in 1986 to 700,000 m3 in 2000. At the same time, the complex has increased annual production 7-fold while reducing the average amount of well water needed to produce a vehicle from 32 m3 to 2.2 m3.

The integrative solutions have been a success for both the region and the production complex, which employs nearly 6,000 local residents and now produces annually some 590,000 engines and 222,000 passenger vehicles.