For General Motors and Audi, being green means more than building EVs.
The automakers are engaged in substantive efforts to reduce their water usage during the manufacturing process. GM unveiled a plan, outlined in its annual sustainability report, to reduce water intensity of its operations by 35% by 2035, compared to a 2010 baseline.
To put that into context, that could result in enough savings to fill about 4,254 Olympic-sized swimming pools. Audi meanwhile plans to significantly alter how it uses water as part of its Mission:Zero environmental program.
“Our aim is to drastically reduce our freshwater consumption and cut the water consumption per produced vehicle in half by 2035,” said Peter Kössler, board member for Production and Logistics. “Where possible, we are already using recycled water that has been used multiple times in the cycle and treated. Our vision is to have closed water cycles at all our production sites.”
GM’s water reduction use plan
GM signed the CEO Water Mandate — a U.N. Global Compact initiative — joining other global business leaders to address challenges around water security, further aligning to the U.N. Sustainable Development Goals.
“As we continue to drive efficiencies in our own manufacturing, we will also work with other endorsing companies to establish, implement and advocate for water stewardship practices that promote corporate water management that benefit people, our communities and our environment,” said Kristen Siemen, GM’s chief sustainability officer.
While the company’s operations are not water intensive, water is required for some manufacturing. Key examples responsible water use will include:
- Zero Liquid Discharge. In the San Luis Potosí Assembly plant in Mexico, the system minimizes the reliance on well water withdrawal, purifying and transforming wastewater into reusable water for the facility’s paint and machining processes, as well as irrigation. GM’s Zero Liquid Discharge system reduces water withdrawal from the local aquifer through its reuse of water.
- Stormwater Reuse. At GM’s Factory Zero plant in Detroit, formerly Detroit-Hamtramck Assembly, the company built a system to reuse stormwater in its cooling towers and manufacturing processes, as well as installed additional stormwater ponds and filtration equipment to limit stormwater discharge to the Detroit River. Additionally, the installed stormwater ponds helped reduce stormwater discharge to the city of Detroit, limiting water stress during heavy storm events.
- Water Treasure Hunts. The company regularly conducts these hunts to help train local plant employees in identifying water efficiency opportunities and implementing solutions.
These moves are part of a larger effort by GM that goes back years to use water responsibly. In 2020 GM made the CDP’s Water A-List for the company’s water stewardship and management practices. CDP is a nonprofit organization that sets the standard for global disclosures for investors, companies, cities, states and regions to manage their environmental impacts.
Audi’s roadmap to responsible use
The company notes that, according to U.N. estimates, 2.2 billion people don’t have regular access to clean water, and the need for clean drinking water worldwide will jump 55% by 2050. To that end, the automaker’s conservation efforts will be very targeted.
Taking the regional circumstances into account allows measures to be implemented in areas where water is particularly valuable, Audi officials note. This way, the ecologically weighted water consumption in production is to be reduced from the current average of around 3.75 cubic meters to around 1.75 cubic meters per produced car by 2035. Some of those efforts will include:
- Elimination of wastewater. Audi Mexico became the first manufacturing facility in the world to make vehicles while producing no wastewater. A biological treatment facility with a downstream ultrafiltration and reverse osmosis system collects the wastewater generated in production, purifies it, and feeds large quantities back into the plant’s water cycle. The location uses the treated water as service water, reuses it in production, or uses it to water the green spaces on the plant premises, for example.
- Closed water cycles. At the Neckarsulm facility, a closed water cycle is to be established between the plant and the neighboring municipal treatment facility of the Unteres Sulmtal wastewater association. The water that returns from the treatment facility is fed into a container in the northern part of the plant premises, whe
re it is treated for reuse in production by means of filter systems and membranes. The water quality is checked continuously throughout this process. Construction on the sytem begins in 2022 and closed cycle will be implemented in 2025.
- Improved service water supply centers. At the Ingolstadt facility, half the wastewater into a circuit where it is treated so it can be reused. Treatment is a three-stage process. It first passes through a chemical/physical facility that neutralizes alkaline and acidic elements and removes heavy metals, before entering the membrane bioreactor. This is where the production water is mixed with sanitary wastewater, and organic components are removed. Any remaining salts are transferred out via reverse osmosis. The purified wastewater is then reintroduced into the water cycle as process water. Audi saves up to 300,000 cubic meters of fresh water per year.
Rainwater retention basins. In use at multiple sites, including the three sites above. Depending upon the weather, up to 250,000 cubic meters of rainwater are used each year. That program is going to be expanded, officials said.