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Ref No. [UMCES[CBL 11-020
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1.0. MERC Background and Objectives
The Maritime Environmental Resource Center (MERC) is a State of Maryland initiative
that provides test facilities, information, and decision tools to address key environmental issues
facing the international maritime industry. The Center’s primary focus is to evaluate the
mechanical and biological efficacy, associated costs, and logistical aspects of ballast water
treatment systems and the economic impacts of ballast water regulations and management
approaches. A full description of MERC’s structure, products, and services can be found at
www.maritime-enviro.org.
To address the need for effective, safe, and reliable ballast water treatment systems to
prevent the introduction of non-native species, MERC has developed as a partnership between
the Maryland Port Administration (MPA), Chesapeake Biological Laboratory/ University of
Maryland Center for Environmental Science (CBL/UMCES), U.S. Maritime Administration
(MARAD), Smithsonian Environmental Research Center (SERC), and University of Maryland
(UMD) to provide independent performance testing and to help facilitate the transition of new
treatment technologies to shipboard implementation and operations.
This evaluation of filter performance was a proof-of-concept demonstration of the
potential of microfiltration membranes to remove ballast water organisms. Detailed protocols
and formal MERC Test Plan can be downloaded at www.maritime-enviro.org.
2.0. Introduction to Technology
This proof of concept focused on 0.1 µm, 20 inch, cartridge membrane filters that
incorporate a proprietary high-flow hydrophilic PTFE (polytetrafluoroethylene) or
asymmetric
polysulfone
filtration media. These membrane filters have been designed for filtration of aqueous
and high-surface-tension liquids, especially where outgassing or bubbles are a concern. Current
applications include high-throughput filling, packaging, and recirculation systems. For ballast
water applications, these filters may be used as a final “polishing” step prior to discharging
ballast water from a vessel that has already been treated by a conventional ballast water
management system.
3.0 Test Protocol Summary
For all trials, the filter developer provided a test skid mounted with three different pre
filters: 20-µm, 10- µm, and 5-µm) and two test filters: 20-inch
0.1 µm PTFE cartridge membrane
filters
, identified as Filter #1 and Filter #5. Each of the six trials included one of the test filters
plus, zero to three pre filters (See trial composition table below).
All trials were conducted during January 2011. The water used for these six trials was
continuously pumped sea-to-sea, from Baltimore Harbor (Patapsco River, MD, in the mesohaline
region of the Chesapeake Bay) into the US Maritime Administration vessel
MV Cape
Washington
via the sea chest.
To simulate water that would initially be pre-filtered by a commercially available ballast
water filtration system, MERC provided the test filter skid with 35-µm filtered challenge water
(labeled below as “challenge water” or “CW”). MERC collected both challenge water and post-
filter samples at the beginning and end of each trial. When applicable, a midpoint sample was
also collected. The timing of sampling and number of samples depended upon the filter system