Water

Water Use in United States Industry

• Water is critical to many industrial processes including processing, washing, diluting, cooling, or transporting a product; or incorporating water into a product. Iron and steel are by far the largest water users in the U.S. followed by petroleum refining, textiles, and pulp and paper which have a much lower total water use. The most important industrial sector however is thermoelectric power production.
• Thermoelectric power production requires water for generating electricity with steam-driven turbine generators - commonly powered by coal. The cheapest and easiest method is to withdraw water from a nearby body of surface water, pass it through the plant and return the heated water to the same body of water. In the US in 2000, thermoelectric-power withdrawals accounted for 48 percent of total water use, and 52 percent of fresh surface-water withdrawals (USGS). Thermoelectric water withdrawals have stabilized since the 1980s, even though population has increased (2).
• Some cities will price large volumes of water cheaply in order to attract industry and support their local economy, particularly around the Great Lakes.

A percentage of industrial water withdrawals are returned to the environment. However, the water is not likely to be returned in the same place, nor the same condition as it was when extracted.

There are three things that make water unusable and polluted: pathogens, chemicals, and lastly thermal pollution.

• Thermal pollution is not as commonly discussed as chemical and pathogen pollution, but it is just as damaging to the ecosystem. When this warmer water is introduced to the aquatic environment, plants and fish, which are adapted to cooler temperatures, can no longer survive in these waters as successfully. Fish and other organisms adapted to specific temperatures ranges can be killed by these thermal shock. Warmer waters decrease dissolved oxygen by lowering the solubility of oxygen in water. Warmer waters will cause aquatic organisms to increase their respiration rates, as well as increase their susceptibility to disease, parasites, and toxic chemicals. Discharge of heated water into shallow water near the shore of a lake may disrupt spawning and kill young fish. Regulation is pendingon (1).

To mitigate this, factories use cooling towers to facilitate the cooling process of water.

(Located in Westport, Kentucky the Ohio River provides water required by this coal-fired power plant. To abate thermal pollution, the power plant uses large cooling towers, which converts water into steam. The emission of the smokestack is largely steam but still contains pollutants.)(3)