Land-Based Evaluation of the Effectiveness of Filtration Technologies

Abstract

This technical report represents the land-based evaluation of the Filtersafe Manta 110 (MTA), Filtersafe BSE101-h-NozzleX (BNX), Filtersafe BSE101-h-Static Nozzle (BSN), and Elite Marine Corp. EMSLQ-250 (EMS) filter systems. This work contributes to ongoing research aimed at reducing the risk of aquatic nuisance species migration in the Laurentian Great Lakes. All filter models evaluated are individual components of type-approved ballast water management systems. This work was conducted to:

1) Determine if current filtration technologies are suitable for ballast water management in the Great Lakes, specifically in cold waters that potentially contain ice.

2) Evaluate each filter’s ability to remove living organisms and suspended solids from freshwater for use in ballast water management systems.

The testing was performed at the Great Waters Research Collaborative Montreal Pier Facility in Superior, WI, in 3 rounds. The first round evaluated the ability of each filter to reduce living organisms and suspended solids from the water, along with analyzing operational parameters (summer 2023). The second round was cold water testing with ice purposely introduced into the water supply (March 2024). The third round (summer 2024) repeated the methods from round 1. Results from rounds 1 and 3 were compared to assess biological and solids removal efficiencies and changes in operational parameters following exposure to ice in round 2. Biological effectiveness was assessed in terms of reducing the density of live organisms in two size classes defined by the United States Coast Guard’s (USCG) Standards for Living Organisms in Ships’ Ballast Water Discharged in U.S. Waters (USCG, 2012): organisms ≥50 µm in minimum dimension (nominally zooplankton), and organisms ≥10 and <50 µm in minimum dimension (nominally protists). Samples collected to evaluate the effect of filtration on water chemistry included total suspended solids (TSS), particulate organic matter (POM), non-purgeable organic carbon (NPOC), dissolved organic carbon (DOC), and ultraviolet transmittance at 254nm (UV-T).

The MTA and BNX filters both successfully performed all rounds of testing during the study, while EMS and BSN filters were unable to complete the testing. MTA and BNX filters’ performances during round 3 were similar to their round 1 performances, indicating that the round 2 ice testing did not substantially damage the filters during testing. Of the filters that completed all three rounds, the filter with a smaller nominal filter rating (MTA) had a greater removal efficiency but required higher energy costs for the ship pumps in the form of pressure loss over the filter.