POWER June 2014 - 24

WATER REGULATIONS
Schedule to Avoid Double Jeopardy?
The schedule of activities in the final rule
is a major interest to the regulated community.
Although the timing of various
required studies and reports is important,
the coordination of the best technology
available (BTA) determination for impingement
mortality (IM) and entrainment mortality
(EM) is of great concern.
Under the 2011 proposed rule, retrofits
to address BTA for IM would have been
required within eight years. The BTA assessment
for EM was understood to follow
BTA assessment. Those sections of the CWA
deal with means of effluent treatment and
protection of water quality for chemical and
physical qualities of water.
Importantly, these qualities are subject to
chemical, physical, and biological treatment
processes that are generally transferable from
one facility to another. In contrast, the interaction
of aquatic organisms with the CWIS
is highly site-specific, and assessment of potential
adverse environmental impacts as well
as alternative control measures can be poorly
transferable among facilities. In its final rule,
the EPA is expected to acknowledge the importance
of site-specific factors in its approach
to BTA for both IM and EM. As we describe
in this article, proper consideration of site-specific
factors will be key to achieving cost-effective
compliance with the final 316(b) rule.
Though it may seem premature to make
recommendations prior to a final rule, based
on the proposed rule, comments made by the
EPA publicly and privately, and the general
tone and approach taken by the EPA in this
particular rulemaking, we believe that the
issues addressed here are sure to be central
to compliance with the final rule. Given the
complexity of the compliance schedule and
process, the need for planning and potentially
assembling a multi-disciplinary team, and the
implications that chosen compliance methods
may have on overall unit operation, we believe
it is important for generating companies
to understand the process and consequences
of various approaches as soon as possible.
Important Site-Specific Factors
When considering rates of IM and EM, potential
adverse environmental impact, and alternatives
for BTA, virtually every aspect of
the assessment can differ dramatically from
facility to facility. Some illustrations of the
variable factors are grouped here into three
broad categories:
■ The nature of impingement and entrainment.
Rates of impingement and entrain24
the
IM-related assessment. Of course, this
put the facility at risk of installing one
technology to address IM and then potentially
having to change that technology
to address EM.
We understand that the EPA has considered
the industry's comments and that
the final rule will postpone the retrofit to
address IM until the BTA for EM has been
determined. A second sidebar discusses
another schedule-related issue: the timing
and purpose of IM and EM monitoring.
ment may vary from facility to facility by
several orders of magnitude. The value
of commercially and recreationally important
species as well as threatened or
endangered species is also highly variable
from facility to facility. The degree to
which a given species will be a " species of
concern " often depends upon the resource
agency. For example, some agencies are
very troubled by the loss of invasive species
that now serve as forage base, while
other agencies believe that the losses of
such invasive species can be discounted.
Additionally, the potential for losses at the
CWIS to actually result in adverse environmental
impact at the ecosystem level
differs among facilities.
■ Potential effectiveness of, and constraints
on, BTA alternatives. Site-related factors
can make a single technology effective at
one site and essentially infeasible at another.
Such factors include weather, debris
loading, temporal variation of the source
water level, the presence of an intake canal
and the availability of additional shoreline,
spatial constraints on construction at
the facility, nearby land uses, and nature
of the generating facility itself. To provide
examples concerning the last two factors:
Operation of evaporative cooling towers
in the proximity of an airport or highway
may present safety issues related to fog
formation and runway/roadway icing, and
a facility's existing condensers may not
withstand increased back-pressure associated
with closed-cycle cooling.
■ The economics of the BTA alternatives, including
costs to the facility and attending
social costs. The factors that affect technology
effectiveness and feasibility often also
affect the technology's costs. For example,
a longer fish return will be more costly and
is also likely to result in less survival of
the returned organisms, particularly in
extreme weather. Beyond these relatively
direct effects, the economic environment,
the price of fuel, the status of the electriwww.powermag.com
POWER
| June 2014
cal grid, and the other site-specific factors
also have the potential to drive facility and
social costs of retrofits. Evaluation of BTA
at a facility should consider-and, in many
cases, quantify-these complex costs as a
part of a site-specific assessment.
As discussed below, though the final rule
is expected to approach BTA for IM and EM
in very different ways, proper accounting of
the numerous site-specific factors must be
considered in assessing the BTA options for
both. In addition, effective communication
to facility staff, company management, and
the National Pollutant Discharge Elimination
System (NPDES) permitting agency (hereafter
NPDES Director) of how these factors favor
or disfavor different BTA options should
be clearly stated in the reports called for by
the final rule.
BTA Approach for Impingement
Mortality
In the final rule's approach to BTA for IM, the
EPA is widely expected to offer streamlined
approaches that equate specific technology
attributes (such as closed-cycle cooling, low
through-screen velocity, existing offshore velocity
caps, and " fish-friendly " screens and
fish returns) to substantial reductions in IM
and designation as BTA (Figure 1). Though
this resembles a " one size fits all " approach,
the availability of different approaches as
well as a de-emphasis on monitoring to demonstrate
compliance should make for a workable
approach to BTA for IM.
The EPA is also expected to delay the need to
assess and retrofit for IM BTA until after a determination
of EM BTA, thus avoiding the potential
for " double jeopardy " in the form of having to
re-retrofit based on an EM assessment that fol1.
Multiple technology options.
Traveling water screens with fish protection
measures, such as this one, are widely expected
to be one of several technology options
for complying with the cooling water
rule's impingement mortality requirements.
Courtesy: HDR
http://www.powermag.com
POWER June 2014

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