Basic HTML Version
MERC+GSI – DRAFT Test Plan
6
Summary of GSI Land-Based Facility and Sampling Design:
GSI evaluates the biological
efficacy ballast water treatments at a
purpose-built, land-based ballast
treatment test facility located in the
Duluth-Superior Harbor of Lake
Superior (right). The facility draws
raw intake water from Duluth-
Superior Harbor at up to 680 m
3
/hr. A
Y-split in the intake piping
simultaneously channels one half of
the flow (up to 340 m
3
/hr) to a
treatment track and one half (also up
to 340 m3/hr) to a matched control
track. The treatment track directs
water through the experimental treatment system and into a 200 m
3
cylindrical retention tank.
The control track by-passes the treatment system and channels water directly into a matched
control retention tank. After storage, water is discharged sequentially from the treatment and
control tanks at m
3
/hr to the harbor or wastewater treatment facility. A detailed design can be
found on page 26 and information on GSI Facility Validation can be found at
www.nemw.org/GSI/.
Water is sampled continuously throughout ballasting functions (intake or discharge)
through in-line sample points. There are 14 in-line sample points at the GSI land-based facility in
total, though not all are in use at this time. Each sample point is made up of three identical
sample ports with a center-located elbow-shaped pitot tube (90
o
) bent towards the direction of
water flow used to sample the water. This pitot design is based on a design developed and
validated by the U.S. Naval Research Laboratory in Key West Florida, and empirically at GSI.
Intake sampling uses sample ports (page 26) at the paired intake sample points of SP#2 and SP#3
on the control and treatment tracks for concurrent sample water collection. Discharge sampling
uses sample ports at the discharge sampling points of SP#9 and SP#10 (page 26), with sequential
collection of control and treatment water.
Sample water at a given sampling location (i.e., intake line of the control track, intake
line of the treatment track, or the discharge line for the control or treatment tracks) is transferred
simultaneously and continuously throughout ballasting operations (intake or discharge) from at
least two of three replicate in-line sample ports to at least two of three replicate 3.8 m
3
sample
collection tubs via a 3.8 cm ID PVC transfer pipe and an automated pressure-controlled
diaphragm valve.
Well-mixed time-integrated 1 l whole water phytoplankton, microbial and water quality
samples are immediately extracted from the replicate sample collection tubs, with the remainder
of the collection tub sample concentrated through 35 µm plankton nets to retain all zooplankton.
Each replicate intake sample (control and treatment tracks) is time-integrated over the 45 minute
fill period and at least 1 m
3
in volume. Each replicate discharge sample is time-integrated over
the 45 minute discharge period and at least is 1 m
3
in volume for control track samples and up to
3 m
3
in volume for treatment track samples. On intake, control and treatment track samples are
collected simultaneously. On discharge, they are collected sequentially, but within two hours of