Originally published as a Schiff Hardin Environmental Update newsletter

This week USEPA proposed for public comment new requirements for cooling water intakes at existing facilities, as required by Section 316(b) of the Clean Water Act (CWA). USEPA touts the proposal as establishing a “common sense framework” setting “flexible technology standards.”

Section 316(b) provides that NPDES permits for facilities with cooling water intake structures must reflect the “best technology available” to minimize harmful impacts to the environment. Requirements of the proposed rule would apply to facilities that withdraw at least 2 mgd of cooling water.

The rule no longer allows restoration as a compliance alternative. The rule also does not, as some anticipated or feared, require existing large power plants to switch to costly closed-cycle cooling technology. The three main parts to the rule are very briefly described below.

Impingement: Existing facilities that withdraw at least 25% of their water from an adjacent water body for cooling purposes and have a design intake flow of greater than 2 mgd are subject to an upper limit on impingement. (The proposal defines ‘impingement’ to mean “[t]he entrapment of all life stages of fish and shellfish on the outer part of an intake structure or against a screening device during periods of intake water withdrawal.”) These facilities can determine which technology would be best suited to meet this limit, including a reduction of intake velocity to 0.5 feet per second or less.

Entrainment: Existing facilities that withdraw at least 125 mgd must conduct studies as part of the NPDES permit application process. Permitting authorities will use those studies to determine whether, and what, site-specific controls will be required to reduce entrainment. (The proposal defines ‘entrainment’ to means “[t]he incorporation of all life stages of fish and shellfish with intake water flow entering and passing through a cooling water intake structure and into a cooling system.”) This process will include an opportunity for public comment.

New Units at Existing Facilities: New units that increase capacity at existing facilities must meet the impingement requirements applicable to existing facilities. (The proposal explains that a “new unit” generally refers to a unit added to an existing facility which increases its capacity and neither replaces an existing unit nor constitutes a “new facility” under 40 C.F.R. 125.83. USEPA’s definition indicates that a replacement unit or repowered unit (as opposed to an additional unit), would not be treated as a new unit.) For entrainment, these affected facilities must install technology or reduce intake velocity so the cooling water system performs as well as a closed-cycle cooling system. The facility can choose to incorporate closed-cycle cooling into the design of the new unit or make other design changes that will allow equivalent reductions in entrainment.

USEPA estimates that more than half of the facilities impacted by the proposed rule already use technologies that are likely to put them into compliance with the proposed standards. The rule does not apply to “new facilities,” which are facilities that commenced construction after January 17, 2002.

A 90-day public comment period will begin on the date of publication in the Federal Register. USEPA must take final action, pursuant to settlement agreement, by July 27, 2012. The rule will technically become effective 60 days from the publication date of the final rulemaking in the Federal Register. Facilities will have to comply with impingement mortality requirements as soon as possible, but can ask for up to eight years to comply.

With respect to entrainment requirements, facilities must comply with a schedule compliance set by the permitting authority. For more information or to comment on the rule, please contact us.