On May 19, US EPA finalized a new rule governing cooling water intake structures at existing facilities. US EPA anticipates that the rule will impact approximately 1,065 existing facilities (521 manufacturing facilities and 544 power plants) nationwide that require a National Pollutant Discharge Elimination System (NPDES) permit under Section 402 of the Clean Water Act (CWA). The new requirements are mostly technology-based, but some facilities may be required to conduct studies and participate in a decision process that includes public input.
The rule is designed to protect aquatic life forms that are pulled into cooling water intake systems at large power, manufacturing, and other industrial complexes. Water cooling intake structures have the potential to kill fish, shrimp, and other aquatic life forms through impingment (pinning them against intake structures) or entrainment (the effects of extreme temperature, physical stress, or chemicals). The rule applies to existing facilities that meet all of the following:
- The facility is a point source that uses or, in the case of new units at an existing facility, proposes to use cooling water from one or more cooling water intake structures, including a cooling water intake structure operated by an independent supplier not otherwise subject to 316(b) requirements that withdraws water from waters of the United States and provides cooling water to the facility by any sort of contract or other arrangement;
- The facility-wide design intake flow for all cooling water intake structures at the facility is greater than 2 mgd;
- The cooling water intake structure withdraws cooling water from waters of the United States; and
- At least 25 percent of the water actually withdrawn is used exclusively for cooling purposes.
The new rule is the ultimate result of a 1995 lawsuit challenging the implementation of rules under Section 316(b) of the CWA governing cooling water intake structures. That lawsuit led to a consent decree which required that US EPA promulgate new rules for cooling water intake structures. The rules developed in 2004 and 2006 under that consent decree were remanded to the US EPA for reconsideration, resulting in the new rule.
Obligations under the new rule vary based on the size of the facility and the volume of cooling water withdrawn on a daily basis. Facilities that withdraw 25% or more of their cooling water from adjacent water bodies and have a design intake of more than 2 million gallons per day will need to meet a best available technology (BAT) requirement, although they will have seven different options available. Facilities that withdraw at least 125 million gallons per day are required to perform studies to determine what site-specific controls may be required to reduce entrainment. Selected site-specific controls will be incorporated into a draft permit, which is subject to public notice and comment requirements. Finally, new units that add electrical generation capacity at an existing facility are required to maintain intake flow at levels similar to a closed-cycle recirculation system.