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D. M. King and M. N. Tamburri
water upon discharge (Option 3c in Table 1 and Figure 2). This could be highly effective
at detecting ballast water discharge violations, but would be extremely costly in terms of
time and money. For example, current shipboard evaluations of biological efficacy during
BWTS testing often involve teams of four to six specially trained technicians, several
hours of sample collection time during ballast water discharge, dozens of hours of sample
analyses, and often costs over
$
100,000 per sampling event. Sampling from a single vessel
to achieve even 50% or 75% confidence that ballast water being discharged meets or
does not meet standards (Options 3a and 3b, respectively, in Figure 2) could cost several
hundred thousand dollars. Using available sampling and analytical methods, the cost per
vessel to achieve closer to 90% or 100% confidence would be significantly higher. Of
course, confidence in the overall verification system depends on the number of vessels
sampled in addition to the intensity of sampling from individual vessels. This means that
achieving high confidence by intensively sampling individual vessels is likely to make an
extensive sampling program prohibitively costly and could result in relatively low overall
confidence levels.
Between these two extremes on the preliminary cost-effectiveness curve are a range
of alternatives that involve applications of indirect measures, such as sensors that monitor
conditions within ballast tanks or in ballast piping during uptake and discharge of ballast
water to validate that they are (and have been) consistent with proven operational param-
eters known to remove or kill planktonic organisms. For example, commercially available
industrial or environmental sensors that quantify dissolved oxygen (for BWTS based on
deoxygenation) or total chlorine (for BWTS based on electrochlorination) generate data
that can serve as reliable proxies to establish with high confidence that a particular treatment
system maintained conditions that have been proven to effectively and consistently meet
discharge standards. The same level of rigorous and independent performance evaluation
and validation required for BWTS certification needs to be applied to sensors that are
used in compliance monitoring. However, there are already established programs, such as
the Alliance for Coastal Technologies in the United States,
27
that currently conduct such
independent sensor testing.
At this preliminary stage of analysis, Figure 2 provides only a basis for posing an op-
erational hypothesis that indirect sensor-based measurements are more cost effective than
any direct ballast water sampling alternative that is not prohibitively costly. Critically im-
portant questions still need to be addressed regarding how emerging technologies involving
sensors and sampling might change the relative position of alternatives in Figure 2. From a
cost-effectiveness and regulatory impact perspective, there are equally important questions
that need to be addressed soon regarding whether spending to increase the volume and sta-
tistical accuracy of direct ballast water sampling will result in more or less favorable shifts
in the cost-effectiveness curve than similar amounts of spending to improve the precision
and reliability of indirect measures of ballast water discharge using sensors.
Results
Benefits of Noncompliance
Since most vessels planning to visit U.S. ports will install a certified BWTS, the main
compliance issue will involve whether ship operators are using them and, if so, properly
operating and maintaining them.
28
Preliminary economic research has indicated that the cost
of purchasing and installing a typical BWTS is in the range of
$
600,000 to
$
1.2 million, and
the annual cost of maintaining and operating it ranges from
$
15,000 to
$
125,000.
29
A rough
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