A new EPA ruling designed to protect aquatic life has created an opportunity within the water industry as more than 1,000 facilities affected by the ruling explore capital investments in equipment and operational adjustments to achieve compliance.
The EPA estimates 2.1 billion fish, crabs and shrimp are killed annually when they are pinned against cooling water intake structures or by being drawn into cooling water systems and affected by heat, chemicals or physical stress, referred to as impingement and entrainment. According to the EPA, cooling water withdrawals are responsible for more than half of surface water withdrawals for all uses in the U.S., including agriculture and municipal uses.
Cooling water systems dissipate heat that is a byproduct of industrial or municipal processes, such as at a nuclear plant. The final rule issued under Section 316(b) of the Clean Water Act applies to facilities that withdraw at least 2 million gallons per day of cooling water from waters of the U.S. including lakes, rivers and oceans, and use at least 25 percent of the water they withdraw exclusively for cooling systems. The ruling affects 521 petroleum refineries, paper and steel mills and other factories, along with 544 power plants, which are the largest consumers of water.
The final ruling took effect on Oct. 14 after many years of litigation, first with electric utility companies and later with environmental groups. Facilities have until July 14, 2018, to comply.
Due to the unique ecosystems of each body of water and the wide range of facilities operating within the U.S., the EPA ruling does not prescribe a single nationally applicable standard to reduce fish entrainment.
Rather, the ruling outlines a number of options to give facility operators latitude in gaining compliance, depending on the particular circumstances. A site-specific plan might utilize a single technology or a multipronged approach from among the following:
• Partial closed-cycle cooling
• Variable speed pumps
• Seasonal outages
• Impingement technologies such as louvers or barrier nets
• Intake location
• Behavioral technologies, such as the use of light or sound barriers
The requirements will be implemented through National Pollutant Discharge Elimination System permits, which generally are administered by state agencies. The ruling calls for site-specific compliance that integrates the best technology available — meaning technology that it is available, feasible and demonstrated at each site. Costs and benefits are to be considered as well in determining the best route to minimizing adverse environmental impact.
The EPA assumes in its rulemaking that entrainment and impingement are proportional to source water intake volume. If a facility reduces its intake flow, it will similarly reduce the amount of organisms subject to impingement and entrainment. By reducing intake velocity, fish and shellfish have a chance to swim away from the intake structure. Variable speed pumps are among technologies cited by the EPA to reduce intake velocity.
Other flow reduction strategies that utilize variable speed pumps include closed-cycle cooling systems and water reuse.
In water reuse applications, variable speed pumps are often utilized to increase efficiencies in the water recycling process, such those used in an oil refinery. Water reuse is a proven technology that reduces water consumption at a facility, though it often involves a capital investment.
Some facilities currently using once-through cooling water systems might be considering retrofitting those systems to closed-cycle cooling systems, which recirculate water instead of discharging it back into the water, thereby eliminating heated effluent that poses harmful thermal effects to aquatic life.
The ruling will have a trickle-down effect throughout the water industry, particularly for pump dealers, distributors and manufacturers. Many of the 1,000-plus industrial facilities affected by this ruling have already begun investigating compliance options — some investing in system redesigns with new pumps or the retrofit of existing systems with variable speed drive pumps. Xylem has already seen new opportunities to help facilities comply, and encourages its partners to offer their expertise to facilities seeking compliance options.