With the entry into force of the IMO Ballast Water Management Convention on 8 September 2017, a substantial number of vessels are required to install a Ballast Water Treatment System (BWTS) by 8 September 2024.
The Ballast Water Management Convention or BWM Convention (full name International Convention for the Control and Management of Ships’ Ballast Water and Sediments, 2004) is a treaty adopted by the International Maritime Organization (IMO) in order to help prevent the spread of potentially harmful aquatic organisms and pathogens in ships’ ballast water.
From 8 September 2017, ships must manage their ballast water so that aquatic organisms and pathogens are removed or rendered harmless before the ballast water is released into a new location. This will help prevent the spread of invasive species as well as potentially harmful pathogens.
IMO is the United Nations specialized agency with responsibility for developing global standards for ship safety and security and for the protection of the marine environment and the atmosphere from any harmful impacts of shipping.
There are two ballast water management standards (D-1 and D-2).
The D-1 standard requires ships to exchange their ballast water in open seas, away from coastal areas. Ideally, this means at least 200 nautical miles from land and in water at least 200 metres deep. By doing this, fewer organisms will survive and so ships will be less likely to introduce potentially harmful species when they release the ballast water.
The D-2 standard specifies the maximum amount of viable organisms allowed to be discharged, including specified indicator microbes harmful to human health.
From the date of entry into force of the BWM Convention, all ships must conform to at least the D-1 standard; and all new ships, to the D-2 standard.
Eventually, all ships will have to conform to the D-2 standard. For most ships, this involves installing special equipment to treat the ballast water.
IMO Member Governments, meeting in the Marine Environment Protection Committee (MEPC), have agreed an implementation timetable for existing ships, linked to the ship’s International Oil Pollution Prevention Certificate (IOPPC) renewal survey.
The difference is that D-1 relates to ballast water exchange, while D-2 specifies the maximum amount of viable organisms allowed to be discharged, including specified indicator microbes harmful to human health.
D-1 standard – The D-1 standard requires ships to conduct an exchange of ballast water such that at least 95% of water by volume is exchanged far away from the coast.
D-2 standard – The D-2 standard specifies that ships can only discharge ballast water that meets the following criteria:
- less than 10 viable organisms per cubic metre which are greater than or equal to 50 micrometres in minimum dimension;
- less than 10 viable organisms per millilitre which are between 10 micrometres and 50 micrometres in minimum dimension;
- less than 1 colony-forming unit (cfu) per 100 mililitres of Toxicogenic Vibrio cholerae;
- less than 250 cfu per 100 millilitres of Escherichia coli; and
- less than 100 cfu per 100 milliliters of Intestinal Enterococci.
Ships may be subject to port State control in any port or offshore terminal of a Party to the BWM Convention. This inspection may include verifying that there is onboard a valid Certificate and an approved ballast water management plan; inspection of the ballast water record book; and/or sampling of the ship’s ballast water, carried out in accordance with the Guidelines for ballast water sampling (G2).
However, the time required to analyse the samples shall not be used as a basis for unduly delaying the operation, movement or departure of the ship
Regulation D-3 of the Convention covers approval requirements for ballast water management systems.
Ballast water management systems must be approved by the Administration taking into account IMO Guidelines. Revised Guidelines for approval of ballast water management systems (G8) were adopted in 2016 and have now been reworked as a draft mandatory Code for approval of ballast water management systems (BWMS Code), expected to be adopted by MEPC 72 in April 2018. The BWMS Code includes robust test and performance specifications as well as detailed requirements for type approval reporting and control and monitoring equipment.
Ballast water management systems which make use of Active Substances or preparations containing one or more Active Substances must in addition be approved by IMO, in accordance with the Procedure for approval of ballast water management systems that make use of Active Substances (G9).
Ballast Water Treatment System (BWTS) is a system designed to remove and destroy/inactive biological organisms (zooplankton, algae, bacteria) from ballast water.
There are commonly three type of Ballast Water Treatment Systems
- Physical disinfection
- Cavitation
- Ultraviolet light
- De-oxygenation
- Others
- Mechanical systems
- Filtration
- Electro-mechanical separation
- Cyclonic separation
- Chemical treatment
- Disinfecting biocides
- Electrolytic chlorination
BWTS Physical disinfection System usually is a two stage approach with filtration followed by disinfection using ultraviolet light. Upon uptake, seawater is first passed through an automatic back-washing filter (1st stage). The filtered seawater then passes through a UV chamber (2nd stage) where ultra-violet light is used to disinfect the water before entering the ballast tank. On discharge, water from the ballast tank is pumped through the UV chamber for a second time to complete the disinfection process prior to discharge. The filter is not used during discharge.
BWTS Mechanical system is a three stage approach: Filtration is an effective method against sediments and various types of organisms. The physical separation can be done either during loading ballast or during the voyage. In this method, the particles are removed with disk and screen filters during ballast loading. These filtration systems can create pressure depressions and a decreased flow rate due to a resistance in the filter elements. Cyclonic Separation is used for those particles with a specific gravity greater than that of water. The particles get separated from the water due to centrifugal forces. It is normally done using hydro-cyclones. Electro-Mechanical Separation where a flocculent is added that attaches to organisms and sediments. They are magnetically separated and then filtered.
BWTS Chemical treatment system is a two stage approach with filtration and electro-chlorination. Upon uptake the sea water is first passed through a automatic back-washing filter (1st stage), and then filtered water passes through a static mixer, where disinfectant generated from the side stream EC Cell Module (2nd stage) is injected to ensure a maximum dose of 10ppm in the treated ballast water prior to entering the ballast tank. At discharge, water from the ballast tanks by-passes the filter and residual concentration of disinfectant is monitored. If required, treated ballast water is neutralized, ensuring compliance with MARPOL discharge limits.
As at September 2017, the treaty has been ratified by more than 60 countries, representing more than 70% of world merchant shipping tonnage.
This envisages a three-stage approach – data gathering; data analysis; and Convention review. Based on the experience and feedback gained, as well as the analysis of the data gathered, draft amendments to the Convention could be put forward for consideration at MEPC 79 (in 2022).
Key players operating in the Global Ballast Water Treatment Systems (BWTS) Market
• Wärtsilä Corporation, • Damen Shipyards Group • ALFA LAVAL • atg Evoqua (Evoqua Water Technologies) • GenSys GmbH • Evac • Coldharbour Marine Ltd. • Ecochlor • GEA Group • ERMA FIRST ESK Engineering S.A. • Ferrate Treatment Technologies, LLC • Veolia Water Technologies • Hitachi • Auramarine Ltd. • Bawat a/s. • Hyde Marine Inc. • MH Systems Inc. • NEI Treatment Systems • Optimarin AS • Mitsui Engineering & Shipbuilding Co. • Mitsubishi Heavy Industries, Ltd. • OceanSaver • Marenco Technology Group Inc. • Panasia • Qingdao Sunrui • JFE Engineering • Qingdao Headway Technology • Techcross • Siemens • Industrie De Nora • MMC Green Technology • Desmi • Bright Sky • Trojan Marinex • Xylem Inc. • Calgon Carbon Corporation
Source: IMO, DNV, Wartsila, Maximize Market Research, Marine Insight
Commenti recenti