Research shows that industrial water consumption is a major drain on the world's limited water supply. How do industries stack up in their water usage habits and which are doing the most for conservation?
By 2030, water demand is expected to exceed current supply by 40 percent, according to the Water Resources Group, an arm of the World Bank.
"In many parts of the world, water scarcity is increasing and rates of growth in agricultural production have been slowing," United Nations Secretary-General Ban Ki-moon said in an address to mark World Water Day last month. "At the same time, climate change is exacerbating risk and unpredictability for farmers, especially for poor farmers in low-income countries...These interlinked challenges are increasing competition between communities and countries for scarce water resources, aggravating old security dilemmas, creating new ones and hampering the achievement of the fundamental human rights to food, water and sanitation."
Experts say water shortages aren't solely about a planetary climate that is becoming warmer and drier. Much of the blame can also be laid on the mismanagement of existing water resources.
Many industrial processes use a staggering amount of water from start to finish. It takes about 270 gallons of water to produce $1 worth of sugar; 200 gallons of water to make $1 worth of pet food; and 140 gallons of water to make $1 worth of milk.
A 2010 report titled Direct and Indirect Water Withdrawals for U.S. Industrial Sectors, conducted by civil engineers at Carnegie Mellon University, handily broke down water usage by industry sector, taking into consideration both direct water usage -- which means bringing water into a manufacturing facility for your industrial process -- and indirect water usage -- when a manufacturing facility is buying items from the supply chain that were manufactured by someone else using water, then incorporating those materials into the finished product.
So which industries use the most water? In terms of direct water usage, nobody beats the agriculture and power-generation industries, which together are responsible for 90 percent of direct water withdrawals. Yet a majority of water usage (about 60 percent) is indirect: about 96 percent of industry sectors use more water indirectly than directly in their supply chains.
Fruit & Vegetable Farming
According to the Carnegie Mellon report, while meat farming is often targeted as an energy- and carbon-intensive sector, it shows up lower on the list in terms of water use per dollar of economic output than fruit, grain and vegetable farming. Notoriously thirsty cash crops like wheat, corn, rice, cotton and sugarcane lead the pack in water usage. (A single 5 lb. bag of refined white sugar uses about 88 gallons of water, most of it from the farming of sugar cane and sugar beets.) Better technology and irrigation management would go a long way toward solving some of these problems.
Many farms are investing in technologies for water management, according to a New York Times report last year. These hardware- and software-based solutions use remote sensing data and satellite images to measure factors such as evaporation and yield, identifying areas where water is being used productively and areas where it's being wasted.
It takes a lot of water to produce energy with the processes we use today. Water is used at almost every stage of energy production, including pumping crude oil, removing pollutants from power plant exhaust, generating steam to run turbines, washing away residue after fossil fuels are burned and keeping power plants cool.
Ultimately, it takes a staggering 95 liters of water to produce one kilowatt-hour of electricity, according to Tamim Younos, head of the Virginia Water Resources Group and a professor of water resources at Virginia Tech. Within the energy industry, the most water-hungry process is the thermoelectric-power industry, which uses copious amounts of water to cool electricity-generating equipment.
Overall, electrical power production uses more water than any other single industrial process, according to IEEE Spectrum. In 2005, about 201,000 million gallons of water were used each day to produce electricity (this figure excludes hydroelectric power). Since surface water is the source for more than 99 percent of the water used for thermoelectric-power generation, energy plants located in coastal areas with a ready supply of salt water for cooling equipment got higher marks in water conservation than those facilities forced to use fresh water.
This leads to the knowledge that not all energy is created equal when it comes to water usage. According to the Virginia Water Resources group, natural gas gets top marks for efficiency in the energy industry, yielding the most energy per unit volume of water consumed. Only about 10 gallons of water are required to extract enough natural gas to generate 1,000 kWh of electricity. By comparison, a coal-fired power plant delivering the same amount of energy would use about 140 gallons of water.
Perhaps most surprising, some biodiesel isn't quite so green in the context of water consumption. More than 180,000 liters of water are required to produce enough soybean-based biodiesel to provide a home with a month's worth of energy. This is because large amounts of water are required for irrigation of the soil in which the soybeans grow, then more water to turn the soybeans into biofuel.
Textiles and Garments
The textile industry is one of the biggest creators of wastewater worldwide. According to the U.S. EPA, it takes 2,900 gallons of water to produce a single pair of jeans. Most of this water is used in what's known as "wet processing" as well as dyeing of fabric.
The textile industry is trying to cut down on its use of water, according to a separate report from the Times, in 2009. The industry doesn't have much choice: both cost-cutting demands and a tightening of environmental regulations are forcing textile and garment companies to evaluate how they use water (particularly if they operate in areas where water is scarce).
While fruit and vegetable agriculture uses more water than meat production, it's not without its own water sins. According to a study by the UNESCO Institute for Water Education, conducted between 1996 and 2005, "29 percent of the total water footprint of the agricultural sector in the world is related to the production of animal products." One-third of that water is used to raise beef cattle.
Another heavy user of water is the beverage industry, which produces sodas, beers, juices and other drinks. Yet it isn't necessarily the production and bottling processes that are to blame. Rather, it is the plants: the beverage industry requires farmed products such as sugar, barley, coffee, chocolate, lemons, vanilla and other plant-derived ingredients. All in all, it takes between 180 and 328 gallons of water to produce a 2-liter bottle of soda, 20 gallons of water to make a pint of beer and nearly 37 gallons of water to produce the ingredients to make a single cup of coffee, according to the Water Footprint Network.
Next time you drive your car, consider this: it takes about 39,000 gallons of water to produce the average domestic car, including the tires. Major water uses in the automotive manufacturing industry include surface treatment and coating, paint spray booths, washing/rinsing/hosing, cooling, air conditioning systems and boilers.
One of the most water-conscious automakers is PSA Peugeot Citroën. While the company uses about 20 million cubic meters of water each year, it strives to clean and return all of it to the environment, purifying the water it uses at all stages of production, including cooling welding machinery, washing sheet steel, painting and water tightness testing.
So what are companies doing about cutting water usage? A 2012 report from sustainable business analyst Verdantix, titled The State of Global Corporate Water Strategies, was compiled after interviewing senior executives in a number of $1 billion or greater firms from different sectors in 10 countries. Verdantix found that formal water strategies are becoming more common. In water-intensive industries, about 90 percent of businesses report having a formal water strategy. The numbers are lower in non-water-intensive industries, but are still substantial: about 60 percent. In water-intensive industries, about 93 percent of companies issue formal reports about their water usage and conservation practices, as do about 77 percent of companies in lower water-intensive industries.
Companies are realizing that as water becomes scarcer in places they manufacture, wasteful production methods present a danger to operations, particularly if local governments turn off the tap or put huge surcharges on water use. It's in the businesses' best interests to put some water conversation programs into place now and wean themselves off wasteful processes in favor of more water-conserving production methods.
To that end, according to the study, companies are using water metering and other technology solutions, such as water accounting, water-footprinting tools (helping facilities get a grip on how much water they are using for which processes) and product lifecycle assessment (LCA) software that helps them outline the environmental impact of their products and processes.
There's still a long way to go. In 2011, the Verdantix study found that most firms perceive water waste as a short-term risk: most of their efforts were focused on cost savings and regulatory compliance strategies. A long-term view, called "water stewardship," was far less common. Water stewardship involves companies working beyond compliance requirements toward permanent sustainability.