Extended Operational and Trade Vocabulary

Ballast Water, Biofouling and Antifouling glossary

The biofouling and ballast vocabulary: the AFS Convention and its certificate and declaration thresholds, ablative and self-polishing antifouling coatings, active substances and biocides, ballast water treatment, and the BWM Convention D-1 and D-2 standards. Grounds each term in the convention or treatment process that governs invasive-species control.

279 defined terms.

Showing 250 on this page (page 1 of 2).

A

Ablative coating: Antifouling paint whose matrix erodes progressively through seawater hydrolysis to expose fresh biocide.
Active substance: Biocide or chemical in an antifouling or ballast water treatment that exerts a biological effect on target organisms.
Acute toxicity: Short-term toxic effect of a discharge or biocide on test organisms, used in BWMS approval under MEPC.300(72).
Aerobic treatment: Treatment relying on dissolved oxygen, generally not used for ballast water disinfection because BWMS often deoxygenate water.
AFS Certificate: International Anti-fouling System Certificate issued under the AFS Convention for ships of 400 GT and above engaged on international voyages.
AFS Convention: International Convention on the Control of Harmful Anti-fouling Systems on Ships, 2001.
AFS Declaration: Declaration on Anti-fouling System required for ships of 24 m or more in length but less than 400 GT engaged on international voyages.
Alexandrium tamarense: Toxic dinoflagellate cyst commonly transported in ballast tank sediment, causing paralytic shellfish poisoning.
Alfa Laval PureBallast: UV-based ballast water treatment system.
Algae bloom: Rapid proliferation of phytoplankton, sometimes seeded by ballast water discharges of cysts.
Alternate Management System (AMS): USCG designation allowing a foreign type-approved BWMS to be used in US waters for up to five years from BWM compliance date.
Anaerobic conditions: Oxygen-depleted conditions inside ballast tanks created by deoxygenation BWMS such as inert gas injection.
Anodic dissolution: Mechanism by which copper-based antifouling biocides are released into seawater.
Antifouling Paint: Coating preventing marine organism attachment to ship hulls.
Antifouling system (AFS): Coating, paint, surface treatment, or device used on a ship to control or prevent attachment of unwanted organisms.
Aquatic invasive species (AIS): Non-indigenous aquatic organism whose introduction causes ecological or economic harm.
Arctic ballast operations: Ballast exchange and treatment under polar conditions where filters and UV chambers may freeze.
Asian clam (Corbicula fluminea): Freshwater bivalve invasive in North America and Europe, partly spread through ballast water.
Asian shore crab (Hemigrapsus sanguineus): Invasive crab established along the US east coast from ballast and hull fouling vectors.
Asparagopsis armata: Invasive red alga transported via hull fouling and ballast.
Australia DAWE Biofouling Management Requirements: Mandatory requirements administered by the Department of Agriculture, Water and the Environment from 15 June 2022 for vessels arriving in Australian territorial seas.
Auxiliary sea chest: Smaller sea chest serving auxiliary cooling systems, identified as a niche area in biofouling management.

B

BalClor (Sunrui): Filtration plus side-stream electrochlorination BWMS by Sunrui Marine Environment Engineering.
Ballast on passage: Voyage condition where the ship carries ballast rather than cargo, often requiring D-1 exchange or D-2 treatment before discharge.
Ballast Tank: Tank dedicated to seawater ballast; close-up surveyed under Enhanced Survey Programme.
Ballast tank coating: Protective coating, typically epoxy, applied to ballast tanks under the IMO Performance Standard for Protective Coatings.
Ballast Water (BW): Water with its suspended matter taken on board to control trim, list, draft, stability, or stresses of a ship.
Ballast Water Exchange (BWE): Replacement of coastal ballast with ocean water at least 200 nautical miles from land and in water at least 200 m deep, the D-1 standard.
Ballast Water Exchange Area: Designated area where exchange may be conducted when geographic constraints prevent meeting the 200 nm and 200 m criteria.
Ballast Water Management Convention (BWM Convention): International Convention for the Control and Management of Ships' Ballast Water and Sediments, adopted 13 February 2004, entered into force 8 September 2017.
Ballast Water Management Plan (BWMP): Ship-specific plan approved by the flag administration describing procedures for BWE or BWMS operation.
Ballast Water Management System (BWMS): Type-approved per MEPC.300(72) BWMS Code.
Ballast Water Record Book (BWRB): Mandatory log of all ballast water operations, including uptake, discharge, exchange, and treatment.
Ballast Water Reporting Form: Pre-arrival declaration of ballast intentions used by US, Australian, and other port authorities.
Ballastace (JFE): Filtration plus electrochlorination BWMS by JFE Engineering, IMO and USCG type approved.
Barnacle (Balanus, Amphibalanus): Calcareous macrofouling crustacean that settles on hulls and niche areas.
Bawat BWMS: One-pass pasteurization plus deoxygenation BWMS using waste heat, made by Bawat A/S of Denmark.
BIMCO: Baltic and International Maritime Council, drafter of standard maritime contracts.
Biocide: Chemical substance that controls harmful organisms, used in antifouling paints and certain BWMS.
Biocide release rate: Mass of active substance released per unit hull area per unit time from an antifouling coating.
Biofilm: Microbial slime layer on submerged surfaces, the first stage of biofouling.
Biofouling: Accumulation of organisms on submerged surfaces.
Biofouling Management Plan (BFMP): Ship-specific plan describing measures to minimize transfer of invasive aquatic species via biofouling, per MEPC.378(80).
Biofouling Record Book (BFRB): Log of biofouling inspections, cleaning, dry-docking, and coating events.
Bioinvasion: Establishment of a non-native species in a new region, often via ballast water or hull fouling.
Black Sea: Inland brackish sea between southeastern Europe and Asia Minor, anoxic below ~150 m.
Bow thruster tunnel: Niche area highly susceptible to biofouling due to low flow when idle.
Brackish water: Water with salinity between fresh water and seawater, roughly 0.5 to 30 PSU.
Bulk Carrier: Single-deck ship for unpackaged dry bulk.
BWMS Code: Code for Approval of Ballast Water Management Systems, MEPC.300(72).

C

California Marine Invasive Species Act (MISA): California state law regulating ballast water and biofouling on vessels entering California ports.
California State Lands Commission (CSLC): Agency administering MISA, requiring Marine Invasive Species Program reporting and biofouling management.
Carcinus maenas: European green crab, invasive on US Pacific and Atlantic coasts, Australia, and South Africa.
Caulerpa taxifolia: Tropical green alga invasive in the Mediterranean, partly via aquarium and hull fouling pathways.
Cavitation BWMS: Treatment using hydrodynamic cavitation to mechanically disrupt organisms, often combined with other methods.
Centric diatom: Group of phytoplankton commonly found in ballast water, target of the 10 to 50 micron D-2 size class.
Chloramine: Secondary disinfection byproduct of some electrochlorination systems.
Chlorate: Disinfection byproduct from electrochlorination, monitored as part of BWMS discharge testing.
Chlorine dioxide (ClO2) BWMS: Treatment injecting ClO2 generated on board for disinfection.
Cionia intestinalis: Solitary ascidian commonly recorded as hull fouling.
Clean hull: Hull condition where macrofouling is absent and microfouling is minimal, per IMO Biofouling Guidelines.
Coliform bacteria: Indicator microorganisms regulated under the D-2 standard as Escherichia coli and intestinal enterococci.
Commissioning test: Mandatory BWMS performance test on installation introduced by BWM.2/Circ.70/Rev.1.
Compliance Monitoring Device (CMD): Optional sensor used to verify BWMS performance in service.
Contingency measure: Action taken when a BWMS fails or BWE cannot be performed safely.
Cooling water sea chest: Sea chest supplying main and auxiliary cooling water intakes, a high-risk niche area.
Copepod: Small crustacean of the subclass Copepoda; the most abundant metazoans in the ocean.
Copper acrylate: Common biocide-binding polymer in self-polishing copolymer antifouling paints.
Copper biocide: Cuprous oxide (Cu2O) or copper thiocyanate, the most common antifouling biocide after the TBT ban.
Copper pyrithione: Booster biocide used with copper in some antifouling formulations.
Corbicula fluminea: Asian clam, freshwater invader spread partly via ballast water.
Corrosion under coating: Failure mode in ballast tank epoxy coatings, accelerated by hot ballast and stress.
Crepidula fornicata: Slipper limpet, native to North America, invasive in European coastal waters.
CRMS-BIOFOUL: New Zealand Craft Risk Management Standard for Biofouling on Vessels Arriving to New Zealand, effective 15 May 2018.
Cumulative effects (ballast): Combined ecological impact of repeated ballast discharges in a port.
Cyanobacteria: Photosynthetic bacteria including *Prochlorococcus*, *Synechococcus*, and *Trichodesmium*.
Cybutryne (Irgarol 1051): AFS biocide banned under MEPC.331(76) from 1 January 2023 on new applications and from 1 January 2026 on existing ships.

D

D-1 Standard: Ballast Water Exchange Standard requiring at least 95 percent volumetric exchange of ballast water.
D-2 Standard: Ballast Water Performance Standard requiring less than 10 viable organisms per cubic meter for >=50 microns, less than 10 viable organisms per milliliter for 10 to 50 microns, and indicator microbe…
D-3 Approval requirement: Requirement that BWMS used to meet D-2 are type approved by the administration.
D-4 Prototype technology approval: Provision allowing prototype BWMS evaluation under specified conditions.
D-5 Convention review: BWM Convention provision for periodic review of standards.
DAWE: Australian Department of Agriculture, Water and the Environment, now DAFF, administering biofouling requirements.
DCOIT (Sea-Nine 211): 4,5-dichloro-2-octyl-4-isothiazolin-3-one, a booster biocide used in antifouling paints.
Deballasting: Discharging ballast water.
Decision support tool: Software used to determine whether ballast operations comply with port and convention requirements.
Deep tank: Cargo tank that can also be used as a ballast tank, more common on older vessels.
Dichlofluanid: Booster biocide used in some antifouling paints.
Dilution method: D-1 BWE method involving simultaneous filling and discharge to achieve volumetric exchange.
Discharge standard: Numerical limit on viable organisms in ballast water at discharge, set by D-2 and similar regulations.
DNV BWMS approval: Class society type approval pathway recognized by many flag administrations.
Documentation of compliance (BW): Onboard records demonstrating BWM Convention compliance including IBWMC, BWMP, and BWRB.
Dreissena polymorpha: Zebra mussel, freshwater bivalve invasive in the North American Great Lakes since 1988 via ballast water.
Dreissena rostriformis bugensis: Quagga mussel, sister invader of zebra mussel in the Great Lakes and Europe.
Dry-dock cleaning: Removal of biofouling and renewal of antifouling coating during dry-docking.
Drydock interval: Time between dry-dockings, affecting biofouling accumulation and AFS performance.

E

Echobot: Hull cleaning and inspection ROV brand.
Ecospeed (Subsea Industries): Glass-flake reinforced vinyl ester hard coating used as a non-toxic foul release surface.
ECOsubsea: Norwegian provider of in-water hull cleaning with capture.
Electrochlorination BWMS: Treatment generating sodium hypochlorite by electrolysis of seawater for disinfection.
Empty refill method: D-1 BWE method involving complete emptying of a tank followed by refilling, achieving at least 95 percent exchange.
Endpoint test (BWMS): Performance verification at discharge after maximum holding time.
Enterococci (intestinal): Indicator microbe regulated under D-2 to less than 100 cfu per 100 mL.
Entry into force (BWM): 8 September 2017, twelve months after the 30 state and 35 percent gross tonnage threshold was met.
Equivalent compliance: Provision under Regulation A-5 for ships engaged on short international voyages such as pleasure craft and SAR.
Escherichia coli: Indicator microbe under D-2 with a limit of less than 250 cfu per 100 mL.
Exemption (Regulation A-4): BWM Convention exemption granted by a port state for vessels on specific routes after risk assessment.
Experience-Building Phase (EBP): BWM Convention phase from 2017 to 2022 for collecting operational data without enforcement penalties for first-failure events.

F

Filtration BWMS: Pre-treatment stage using disc, screen, or candle filters to remove organisms larger than typically 40 to 50 microns.
Fleet Cleaner: Dutch provider of in-water hull cleaning with biofouling capture.
Flow rate (BWMS): Treatment rated capacity (TRC) in m3 per hour, used to size and approve BWMS.
Flow-through method: D-1 BWE method pumping at least three times the tank volume of replacement water.
Fluoropolymer coating: Foul release coating using fluorinated polymer surface chemistry, e.g., Intersleek 700.
Forced ventilation: Used in ozone BWMS spaces to prevent accumulation of residual gas.
Foul Release Coating: Coating that prevents firm attachment of biofouling.
Free chlorine (TRO): Total residual oxidant measured in electrochlorination and chlorine dioxide BWMS effluent.
Freshwater BWMS challenge: Difficulty for chlorine-based systems in freshwater because of low conductivity.

G

G8 Guidelines: Original Guidelines for Approval of Ballast Water Management Systems, replaced by MEPC.300(72) BWMS Code.
G9 Guidelines: Procedure for approval of BWMS that make use of Active Substances.
Galapagos PSSA: Particularly Sensitive Sea Area designated by IMO in 2005 with associated Areas To Be Avoided.
GESAMP-BWWG: Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection, Ballast Water Working Group, evaluating BWMS active substances.
GloBallast Programme: GEF, UNDP, and IMO partnership (2000 to 2017) that built ballast water capacity worldwide.
GloEn-Patrol (Panasia): Filtration plus UV BWMS by Panasia of Korea.
GloFouling Partnerships: GEF, UNDP, and IMO project on biofouling management started 2018.
Golden mussel (Limnoperna fortunei): Freshwater bivalve invasive in South America, spread partly through ballast water.
Great Barrier Reef PSSA: Earliest IMO PSSA designation in 1990, expanded in 2005.
Great Lakes ballast regulation: Joint US and Canadian regulation requiring saltwater flushing for vessels entering the Seaway, codified as NOBOB management.
Greensea Systems: US provider of marine robotics and hull crawler navigation used for proactive cleaning.

H

Hard insoluble matrix paint: Antifouling coating where the resin matrix does not dissolve, relying solely on biocide leaching.
HEMPAGUARD (Hempel): Silicone hydrogel based foul release coating with low biocide content.
HEMPEL Globic: Self-polishing copolymer antifouling brand.
HiBallast (Hyundai): Filtration plus electrolysis BWMS by Hyundai Heavy Industries.
Holding time: Minimum time between treatment and discharge required to meet D-2 in some BWMS, particularly chemical injection systems.
Hull cleaning: In-water hull cleaning subject to biofouling rules.
Hull crawler: Magnetic or vacuum-attached robotic platform for inspection or cleaning.
Hull husbandry: General term for inspection, cleaning, and maintenance of the underwater hull.
HullWiper: Brush-free, ROV-based in-water cleaning service with filtration and capture.
Hyde GUARDIAN: Filtration plus medium-pressure UV BWMS by Hyde Marine, now part of De Nora.
Hydraulic disturbance: Mechanism for organism mortality through pumps, cavitation, and pressure changes.
Hydrogen peroxide treatment: Oxidative BWMS chemistry used by some systems for disinfection.
Hypobromous acid: Effective biocide formed when chlorine reacts with bromide in seawater electrochlorination.
Hypochlorous acid: Primary biocide in electrochlorination BWMS.

I

IBWMC: International Ballast Water Management Certificate issued under the BWM Convention for ships of 400 GT and above.
ICS: International Chamber of Shipping, industry body.
In-water cleaning (IWC): Cleaning of ships' underwater surfaces while afloat.
Indicator microbes: D-2 regulated organisms: Vibrio cholerae O1 and O139, E. coli, and intestinal enterococci.
Initial inspection (BW): First survey after BWMS installation for issue of the IBWMC.
Initial survey (AFS): Survey for the issuance of the AFS Certificate verifying compliance with prohibitions.
Inspection regime (Australia): Biosecurity inspections by Australian Government biosecurity officers on arrival.
Intermediate Survey: Class survey between Special Surveys.
International Anti-fouling System Certificate: Statutory certificate under the AFS Convention.
International Ballast Water Management Certificate (IBWMC): Statutory certificate verifying BWM Convention compliance.
Intersleek (International, AkzoNobel): Range of fluoropolymer and silicone foul release coatings.
Intersmooth: Self-polishing copolymer antifouling paint range.
Invasive aquatic species (IAS): IMO terminology for non-native aquatic species causing harm in the receiving environment.

J

JFE Engineering Ballastace: Filtration plus electrochlorination BWMS by JFE Engineering of Japan.
Jotun SeaLion Resilient: Silicone foul release coating.
Jotun SeaQuantum: Self-polishing copolymer silyl methacrylate antifouling brand.

K

KORDI BWMS testing: Korea Ocean Research and Development Institute, historical land-based BWMS test facility.

L

Land-based test (LBT): BWMS performance test conducted at an accredited shore facility under MEPC.300(72).
Leaching rate: Mass of antifouling biocide released per unit area per day; regulated by some jurisdictions.
Limnoperna fortunei: Golden mussel, invasive freshwater bivalve.
Lionfish (Pterois volitans and Pterois miles): Indo-Pacific species invasive in the western Atlantic and Caribbean, primarily aquarium trade origin.
Low salinity challenge: Operating condition that reduces efficacy of UV (due to turbidity) and chlorine BWMS (due to low chloride).

M

Macrofouling: Visible fouling community including barnacles, mussels, tubeworms, and macroalgae.
Major non-conformity (BWMS): PSC finding indicating that BWMS is inoperative or substantially non-compliant.
Medetomidine: Antifouling active substance acting as octopamine receptor agonist on barnacle larvae, used in some Selektope formulations.
MEPC.1/Circ.792: 2012 Guidance for Minimizing the Transfer of Invasive Aquatic Species as Biofouling for Recreational Craft.
MEPC.1/Circ.906: 2023 Revised Guidelines for the Reduction of Underwater Radiated Noise from Shipping.
MEPC.207(62): 2011 IMO Guidelines for the Control and Management of Ships' Biofouling, the original biofouling guidelines.
MEPC.300(72): 2018 Code for Approval of Ballast Water Management Systems (BWMS Code), mandatory under the BWM Convention.
MEPC.331(76): 2021 AFS Convention amendment adding cybutryne to the prohibited active substances.
MEPC.378(80): 2023 Revised Guidelines for the Control and Management of Ships' Biofouling.
Microfouling: Biofilm and slime community of bacteria, diatoms, and protists.
Mnemiopsis leidyi: Comb jelly native to the US east coast, invasive in the Black Sea (1980s), Caspian Sea, and Baltic via ballast water.
Monitoring and reporting (BW): Sampling and analytical methods used to verify D-2 compliance.
Most Probable Number (MPN): Statistical microbiological method used for indicator microbe enumeration in ballast water.
Mussel (Mytilus, Perna): Bivalve mollusks common in hull macrofouling.

N

Native species: Species occurring naturally in a defined biogeographic region.
Niche area: Ship area more susceptible to biofouling such as sea chests, bow thrusters, rudder hinges, propeller shafts, and stabilizer fins.
Nitrogen deoxygenation: BWMS approach injecting nitrogen to displace oxygen.
NOBOB: No Ballast on Board, a vessel condition that still requires sediment management because residual water and sediment remain.
Non-indigenous species (NIS): Species occurring outside its native range.
Notilo Plus: French provider of underwater drones (e.g., Seasam) used for hull inspection.

O

OceanSaver BWMS: Filtration plus electrodialysis BWMS, vendor entered restructuring in 2017.
Optimarin Ballast System (OBS): Filtration plus medium-pressure UV BWMS by Optimarin AS of Norway.
Organotin compound: Class of biocides including TBT, prohibited under the AFS Convention since 1 January 2008.
Overboard discharge: Release of treated or exchanged ballast water through dedicated discharge line.
Ozone BWMS: Treatment injecting ozone gas into ballast for oxidative disinfection.

P

Pacific oyster (Magallana gigas): Cultivated species now invasive in many coastal waters partly via hull fouling and aquaculture.
Panasia GloEn-Patrol: Filtration plus UV BWMS by Panasia Korea.
Particularly Sensitive Sea Area (PSSA): Area designated by IMO needing special protection due to ecological, socio-economic, or scientific significance.
Pasteurization BWMS: Thermal inactivation approach, used by Bawat among others.
Performance Standard for Protective Coatings (PSPC): IMO Res. MSC.215(82).
PPG SIGMAGLIDE: Silicone hydrogel based foul release coating.
Pre-arrival ballast water report: Mandatory notification to port states such as USCG, Australia, and NZ.
Pressure-vacuum valve (ballast tank): Vent fitting that prevents over- or under-pressurization during ballast operations.
Primary treatment (BWMS): Pre-treatment step, typically filtration.
Proactive in-water cleaning: Removal of biofilm and incipient fouling using soft brushes or water jets without removing AFS biocide layer.
Propeller fouling: Loss of propulsive efficiency due to roughness; addressed by polishing or coating.
PSC inspection (BW and AFS): Port state control verification of certificates, plans, records, and BWMS operation.
PureBallast (Alfa Laval): Industry-leading UV BWMS line, latest version PureBallast 3.2.

Q

Quagga mussel (Dreissena rostriformis bugensis): Freshwater invasive bivalve related to zebra mussel.
Quarantine area (port): Designated berth or anchorage where biosecurity inspection or treatment occurs.

R

Re-deployment (BWMS): Reinstallation after refit, requiring commissioning testing under BWM.2/Circ.70/Rev.1.
Reactive in-water cleaning: Removal of established macrofouling, requires capture systems to comply with most jurisdictions.
Reception facility (sediment): Shore facility to receive sediment from ballast tank cleaning.
Record of construction (AFS): Documentation accompanying AFS Certificate showing coatings applied.
Renewal survey (AFS): Survey at coating renewal verifying compliance.
Renewal survey (BW): Five-yearly survey for renewal of the IBWMC.
Residual disinfection byproducts (DBP): Trihalomethanes, haloacetic acids, chlorate, and bromate produced by oxidative BWMS, regulated through GESAMP-BWWG approval.
Risk assessment (Regulation A-4): Procedure for granting BWM exemptions based on biogeographic and operational analysis.
ROV (Remotely Operated Vehicle): Tethered underwater robot.
Rudder hinge: Niche area with crevices and stagnation prone to fouling.

S

Saba Bank PSSA: PSSA designated by IMO in 2012, located in the Caribbean.
Sabella spallanzanii: Mediterranean fanworm, invasive in Australia and New Zealand, hull fouling vector.
Sample point (BWMS): Designated location for in-line sampling of treated ballast water for compliance testing.
Sea chest: Hull recess for seawater intake.
Sea chest grating: Perforated cover over a sea chest, often coated with antifouling to limit fouling.
Sea-Nine 211 (DCOIT): Antifouling booster biocide by Rohm and Haas / Dow.
SeaQuantum (Jotun): Silyl methacrylate self-polishing copolymer antifouling.
Seasam (Notilo Plus): Autonomous hull inspection underwater drone.
Secondary treatment (BWMS): Disinfection step following filtration, e.g., UV, electrochlorination, or chemical injection.
Sediment management: Removal and disposal of accumulated tank sediments to reduce IAS transfer risk under Regulation B-5.
Selektope (medetomidine): Antifouling active substance produced by I-Tech AB, deters barnacle settlement.
Self-polishing copolymer (SPC): Antifouling matrix that hydrolyses at a controlled rate, releasing biocide and renewing the surface.
Sequential method: D-1 BWE method involving emptying and refilling tanks one at a time.
Silicone fouling release coating: Low surface energy coating, e.g., Intersleek 700, Hempasil X3, that resists adhesion of fouling.
Silicone hydrogel coating: Surface chemistry combining silicone and a hydrophilic hydrogel layer, e.g., HEMPAGUARD.
Single-pass BWMS: System that treats water in one transit through the equipment, with no holding time required.
Slime layer: Microfouling biofilm of bacteria and diatoms forming within days of immersion.
Slipper limpet (Crepidula fornicata): Invasive gastropod in European waters.
SPS (Sanitary and Phytosanitary): WTO framework relevant to biosecurity import controls.
Strait of Bonifacio PSSA: PSSA designated by IMO in 2011 between Corsica and Sardinia.
Stress test (BWMS): Land-based test using challenge water of defined organism density and water quality.
Subsea Industries Ecospeed: Hard, non-toxic, glass-flake reinforced hull coating designed for in-water cleaning.
Sunrui BalClor: Filtration plus electrochlorination BWMS by Sunrui Marine Environment Engineering.

T

TBT (Tributyltin): Organotin biocide formerly used in antifouling, banned by AFS Convention.
Techcross Electro-Cleen System (ECS): Filterless electrolysis BWMS by Techcross of Korea.
Test organism (BWMS): Standardized challenge organisms used in BWMS approval, including Tetraselmis suecica and Brachionus plicatilis.
Tetraselmis suecica: Marine microalga used as the 10 to 50 micron test organism.
Thalassiosira pseudonana: Diatom used in BWMS challenge studies.
Thermal treatment: Heating ballast to lethal temperatures, used by pasteurization BWMS.
Total Residual Oxidant (TRO): Concentration of oxidizing species in treated water; controlled to meet discharge limits.
Tralopyril: Antifouling booster biocide marketed as Econea by Janssen PMP.
Treatment Rated Capacity (TRC): Maximum continuous flow rate at which a BWMS is type approved.
Tributyltin (TBT): Organotin compound banned under the AFS Convention.
Tubbataha Reefs PSSA: PSSA designated by IMO in 2017 in the Sulu Sea, Philippines.
Tubeworm (Hydroides elegans, Ficopomatus enigmaticus): Calcareous tubeworms among the most invasive hull fouling organisms.
Two-pass BWMS: System that treats water both at uptake and at discharge.