Challenges for Water Resources
Moderator: James S. Alder, Vice President, Operations and Technical, Celanese Corporation
Speakers: Paul Freedman, President, Limnotech
M. Michael Hightower, Water for Energy Project Lead, Sandia National Laboratories
As populations, water-intensive manufacturing, and requirements for agriculture continue to expand in such regions as India, China, and the American Southwest, water-quality and availability issues are becoming urgent. Water stewardship has become a critical issue in both the political and business spheres.
Paul Freedman, president of Limnotech, opened his remarks by reviewing the current supply picture. Most water on the planet is sea water. Only 3 percent of the water is fresh, with most of that supply contained in glaciers or aquifers. In addition, surface water is declining, with several notable examples given, including the Colorado River. In many ways water is a local issue: the Great Lakes hold 20 percent of the world’s fresh water, which means availability is not an issue in that region. Water is not like carbon and CO2, where a local emission has world impact. Drivers on the demand side include population growth, food and agriculture, urbanization (concentrated local use), a rising standard of living, and climate change.
As corporate water stewardship becomes the norm, companies are concerned with a number of risks:
- physical risk—can they make their product? (Beverage makers have faced periodic shutdowns, along with energy companies in the southeastern United States);
- regulatory risk—new facility approvals or renewal of permits; and
- reputational risk—investors and the general public expect environmental stewardship, and so ISO standards are being developed to standardize water risk reporting.
Freedman observed that the chemical industry is somewhat behind the curve in this area. The industry has traditionally viewed water as a cost issue, and that cost has been low compared with other costs, such as feedstocks.
Freedman explained how companies are defining their “water footprint”—an attempt to create an analog to the well-known carbon footprint. This concept requires long-term thinking: how much embedded or virtual water is required? If a company bottles a beverage, how much water was required to grow the sugar? Freedman gave several examples: a slice of bread represents 10 liters of water; a glass of orange juice requires 128 liters; and a cup of coffee requires 140 liters. In comparison, in the chemical industry, 8 to 12 kilograms of water are required to derive 1 kilogram of polyolefin. He also reviewed several other tools being used in risk assessments. A global water tool can be used to screen, using geography, which operations are or will likely be at risk. The World Resource Institute has developed a tool using twenty-one metrics that identifies risks related to water and can be used in making plant location decisions. The World Wildlife Fund has a model that ranks risk by area for particular types of industry.
Freedman closed by posing a number of opportunities that new technologies might address: improvements in drinking water and sanitation, agricultural improvements, recovering minerals or nutrients from gray water, and new membrane materials for treatment plants.
The second speaker, M. Michael Hightower from Sandia National Laboratories, began his remarks by reviewing a number of studies done by the U.S. government. He showed maps defining critical regions. Surface water has been exhausted in many areas; these areas have been overpumped, using nonrechargeable “fossil” water largely owing to agricultural needs. The same trends are apparent on a worldwide basis. One response is water reuse, and desalinization has increased by 10 percent. However, treatment of salt water brings with it increased energy challenges.
Hightower moved on to discuss the water–energy nexus. A lot of water is required to generate energy, and treating water is energy intensive. Shifts in energy production can bring major changes in water use. Several pertinent examples were given:
- One megawatt hour of electricity generated from fossil fuel requires 1,000 liters of water, with natural gas requiring somewhat less.
- Concentrated solar requires several thousand liters per megawatt hour.
- Carbon sequestration is a big consumer in the medium that captures the CO2.
- Grain ethanol requires a lot of water and energy.
- Fracking the Marcellus shale requires 2.5 million gallons per day per well, most of which is not recovered.
Hightower closed with a discussion of R&D challenges:
- new materials for membranes in reverse osmosis;
- removal of materials concentrated by reuse of agricultural water;
- recovery of phosphorus from gray water; and
- new battery materials.
Session participants then discussed a number of issues raised by the presentations:
- Which use segment is the most important target for conservation? Consensus: agriculture.
- Isn’t water a closed system (the water cycle)? Answer: yes, but it can be removed from a local system.
- Climate change increases the extremity of local overage or underage.