Water consumption in automotive manufacturing

The global automotive industry is a major consumer of water for various production processes. According to some estimates, producing a car uses over 39,000 gallons of water, and whether tyre production is included varies by estimate.

Major water uses in the automotive manufacturing industry includes surface treatment and coating, paint spray booths, washing, rinsing, hosing, cooling, air-conditioning systems and boilers. The component manufacturing segment has its own list of water-intensive processes.

In addition to the use of water for these processes, there is the matter of wastewater, which then needs to be treated to high standards in order to meet environmental regulations.

According to the US EPA, the true cost of using water is often misunderstood in industry, resulting in poor management choices regarding how water is used.

The common perception is that water is cheap and this leads to liberal use of water, making conservation measures difficult to justify. In fact, the cost of using water within various processes could be more expensive than originally perceived.

Benefits of Saving Water

There are, of course, significant benefits of using water more judiciously in automotive manufacturing, such as reducing the energy used in water pumping and delivery systems. The Australian Industry Group (AIG) lists out a few, such as cost, energy consumption, wastes and carbon footprint. Indirectly, this also results in better production efficiency.

Importantly, it must be recognised that the cost of water is made up not just of the purchase price, but also the handling, heating, holding, treating and discharging. And water costs and energy costs are linked; for instance, cutting down on hot water for cleaning translates into a reduction in heating costs as well.

AIG further adds that wastewater treatment often results in the generation of prescribed wastes, the disposal of which is costly. In addition, cutting energy use has a direct impact on carbon footprint.

Water conservation options

There are many ways a vehicle manufacturer can conserve water in manufacturing operations. These include improving energy efficiency of operations; installing flow restrictions on tap water supply line; dry sweeping all areas before hosing, and eliminating leaks, on the lower end of the cost spectrum.

At the other end of the cost spectrum, a vehicle manufacturer could reuse water from a critical rinse stage in a less critical rinse stage; treat site wastewater and recycle internally; install rain water tanks; undertake storm water harvesting; use groundwater, or use Class A recycled water, especially in boilers and cooling towers, states the AIG.