The U.S. Environmental Protection Agency (EPA) (on May 19) finalized standards for cooling water systems at large power plants and factories. This final rule is required by the Clean Water Act to address site-specific challenges.
According to the EPA, an estimated 2.1 billion fish, crabs, and shrimp are killed annually by being pinned against cooling water intake structures (impingement) or being drawn into cooling water systems and affected by heat, chemicals, or physical stress (entrainment).
The final rule establishes requirements under the Clean Water Act for all existing power generating facilities and existing manufacturing and industrial facilities that withdraw more than 2 million gallons per day of water from waters of the U.S. and use at least 25 percent of the water they withdraw exclusively for cooling purposes.
The national requirements, which will be implemented through National Pollutant Discharge Elimination System (NPDES) permits, are applicable to the location, design, construction, and capacity of cooling water intake structures at these facilities and are based on the best technology available for minimizing environmental impact. The rule establishes a strong baseline level of protection and then allows additional safeguards for aquatic life to be developed through site-specific analysis, an approach that ensures the best technology available is used. It puts implementation analysis in the hands of the permit writers so requirements can be tailored to the particular facility.
There are three components to the final regulation.
- Existing facilities that withdraw at least 25 percent of their water from an adjacent waterbody exclusively for cooling purposes and have a design intake flow of greater than 2 million gallons per day are required to reduce fish impingement. To ensure flexibility, the owner or operator of the facility will be able to choose one of seven options for meeting best technology available requirements for reducing impingement.
- Facilities that withdraw very large amounts of water – at least 125 million gallons per day – are required to conduct studies to help the permitting authority determine what site-specific entrainment mortality controls, if any, will be required. This process will include public input.
- New units at an existing facility that are built to increase the generating capacity of the facility are be required to reduce the intake flow to a level similar to a closed cycle, recirculation system. Closed cycle systems are the most effective at reducing entrainment. This can be done by incorporating a closed-cycle system into the design of the new unit, or by making other design changes equivalent to the reductions associated with closed-cycle cooling.
More information: http://water.epa.gov/lawsregs/lawsguidance/cwa/316b/