title: Sample port design for ballast water sampling: Refinement of guidance regarding the isokinetic diameter.
abstract: By using an appropriate in-line sampling system, it is possible to obtain representative samples of ballast water from the main ballast line. An important parameter of the sampling port is its "isokinetic diameter" (DISO), which is the diameter calculated to determine the velocity of water in the sample port relative to the velocity of the water in the main ballast line. The guidance in the U.S. Environmental Technology Verification (ETV) program protocol suggests increasing the diameter from 1.0× DISO (in which velocity in the sample port is equivalent to velocity in the main line) to 1.5-2.0× DISO. In this manner, flow velocity is slowed-and mortality of organisms is theoretically minimized-as water enters the sample port. This report describes field and laboratory trials, as well as computational fluid dynamics modeling, to refine this guidance. From this work, a DISO of 1.0-2.0× (smaller diameter sample ports) is recommended.
authors.affiliation: Excet, Inc., Springfield, VA 22151, United States. Electronic address: timothy.wier.ctr@nrl.navy.mil.
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Wier
authors.affiliation: Excet, Inc., Springfield, VA 22151, United States.
authors.forename: Cameron S
authors.initials: CS
authors.lastname: Moser
authors.affiliation: Battenkill Technologies, Inc., Manchester Center, VT 05255, United States.
authors.forename: Jonathan F
authors.initials: JF
authors.lastname: Grant
authors.affiliation: Excet, Inc., Springfield, VA 22151, United States.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: First
authors.affiliation: Excet, Inc., Springfield, VA 22151, United States.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Riley
authors.affiliation: Excet, Inc., Springfield, VA 22151, United States.
authors.forename: Stephanie H
authors.initials: SH
authors.lastname: Robbins-Wamsley
authors.affiliation: Chemistry Division, Naval Research Laboratory, Code 6136, Key West, FL 33041, United States.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Drake
mesh_terms: D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D008962:Models, Theoretical; D012767:Ships; D014481:United States; D014867:Water / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis
chemical_list: D014873:Water Pollutants; D014867:Water
keywords: Aquatic nuisance species; Ballast water; Compliance; Invasive species; Sampling