Ballast Water

• What Ballast Water is and why it's a problem 
Ballast is defined as any solid or liquid that is brought on board a vessel to increase the draft, change the trim, regulate the stability or to maintain stress loads within acceptable limits.
With the introduction of steel-hulled vessels and pumping technology, water became the ballast of choice. Water can be easily pumped in and out of ballast tanks, requires little manpower, and as long as tanks are kept full, poses little to no stability problems.

There are thousands of aquatic species that may be carried in ships' ballast water, including bacteria and other microbes, micro-algae, and various life stages of aquatic plant and animal species. 

• Ballast Water Certficates 
Once the BWM Convention has entered into force all ships over 400 gt are subject to surveys and certification, instead, all ships of 400 gross tonnes (gt) and above will be required to have on board an approved Ballast Water Management Plan and a Ballast Water Record Book, and to be surveyed and issued with an International Ballast Water Management Certificate.

For ships whose flag administration has not ratified the BWM Convention a certificate or statement of compliance can be issued. 
On completion of an initial survey, an International Ballast Water Certificate will be issued for a ship whose flag has ratified the BWM Convention; for other ships, a Ballast Water Management Certificate of Compliance will be issued.

Both the Certificates and the Statement will be valid for five years subject to annual, intermediate and renewal surveys. 

• IMO (International Maritime Organization)
The IMO has published Interim Survey Guidelines (contained in the Circular, BWM.2/Circ.7) and it is expected that these will be incorporated into the IMO's Harmonised System of Survey and Certification Guidelines (Resolution A.997(25)) once the BWM Convention enters into force. 

Ships may be subject to inspections by port states to determine whether they comply with the BWM Convention's requirements.
These inspections are limited to: 
– verifying certification 
– inspecting the ballast water record book 
– sampling ballast water in accordance with the IMO's guidelines. 

BWM treatment system

Ballast Water treatment systems must have a type approval certificate in compliance with the IMO Guidelines for the Approval of Ballast Water Management Systems (Resolution MEPC. 174(58)), which updated Resolution MEPC.125(53)).

There are a number of approved ballast water treatment systems available and there are many more systems which are expected to be submitted for test and approval in the near future; there will be significant lead times for some of the more popular systems, particularly in the year leading up to entry into force of the BWM Convention.

When selecting a treatment system, you need to consider many factors: 
– ship type 
– max and min ballasting and de-ballasting rates
– ballast capacity 
– space required (foot print and volume)
– flexibility of location of system components
– the effects of pressure drop
– integration with existing systems
– whether it is certified intrinsically safe
– power availability 
– health and safety 
– effects on tank structure/coatings
– availability of consumables, spares and support (servicing)
– additional crew workload
– crew training 
– capital and operating cost
– system availability and delivery time. 

Download and compile the Checklist, Zephyr will help you to design the BWTS best fitting your ship.