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As noted previously, MERC protocols, challenge conditions and testing infrastructure are based on the
essential features of the G8 guidelines and ETV protocols for the verification of BWT technologies. To
that end, all BWTS will be evaluated on the following:
•
Biological treatment efficacy
•
Operation and maintenance
•
Reliability
•
Cost factors
•
Environmental acceptability
•
Safety
Biological treatment efficacy is measured in terms of the concentration of selected organism size classes
in the challenge water and the treated discharge. Operation and maintenance includes the labor, expertise,
equipment, and consumables required to operate the system to achieve the stated performance goals and
objectives. Reliability is a statistical measure of the number of failures (either qualitative or quantitative)
per known quantity of test cycles. Cost factors include only those factors that can be verified, such as
labor hours to operate and maintain the system, expendable material, such as filter cartridges, and pounds
or gallons of chemicals consumed by the treatment system. Environmental acceptability assesses ballast
water quality following treatment for factors such as whether the treated water meets acceptable water
quality characteristics. Safety factors include any treatment-specific considerations that may pose a threat
to the safety of the operator or shipboard operations.
Another basic premise in the design for the test design is that BWTS are designed to function effectively
in the full range of water quality characteristics that will be encountered under shipboard operational
conditions. By challenging the treatment systems with these conditions, it is assumed treatment will be
effective under less demanding conditions. The measurement methods for evaluating the status of the
challenge water quality conditions are described in Section B.4.
Biological efficacy will be evaluated as function of a system’s ability to kill or remove organisms that are
naturally occurring and represent the more robust ambient populations at the test site. A minimum total
input concentration of living organisms, by size class, as describe in A.6.1. Upon intake, challenge water
conditions will be determined for each test cycle prior to water entry into control tanks, Samples of
treated water are collected immediately downstream of the treatment system. At the end of the hold time
specified in the test plan, samples are collected upon discharge from both the treated and control holding
tanks. Treatment tests will evaluate equipment at operational flow rates defined by the vendor’s O&M
manual. A minimum of 400 m
3
per tank, divided equally into control and treated tanks shall be processed
in each test cycle.
B.2.
Sampling Method Requirements
As described in Section A.6, MERC BWTS testing takes place on MERC’s Mobile Test Platform, which
may be located at three sites, Baltimore Harbor, Baltimore, MD; Norfolk, VA; or the Anacostia River in
Washington, DC. Ambient conditions at each site are employed as the physical/chemical challenge
conditions, although certain parameters may be augmented to meet IMO or ETV requirements. These will
be detailed in the Test Plan. Biological challenge conditions are also ambient but can be enhanced, if
required.
Flow control valves and system logic assure that sample flow rates are equivalent and proportional to
intake and discharge flow rates throughout each operation. Flow rates are recorded every 15 seconds