.bwm

.ballast water management

International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) was adopted on 13 February 2004.  entered into force on 8 September 2017.

The convention applies to all the ships that carry ballast. There are few logical exemptions such as a ship that carries permanent ballast in sealed tanks, which does not need to be discharged. Ballast water convention is to prevent pollution from ballast water from one location and discharged into different ecology.

Ballast water management (BWM) convention provides two ways of doing that.

Regulation D1. Ballast water exchange standard

The first standard is to replace the ballast water in mid sea. This method is based on the fact that the invader species from coastal water cannot survive in deep waters and deep water species cannot survive in coastal waters. When replacing the ballast water at deep sea, BWM convention regulation D1 requires that at least 95% of the ballast water need to be exchanged.

And there are two ways to do that.

Sequential method or simply Pump-in, pump-out method

The first method is to deballast at least 95% of the volume of ballast water from the tank and then re-fill it. This is called the “Sequential method or simply Pump-in, pump-out method)”.

For example, let us say we need to exchange the ballast water from a ballast tank that has 1000 m3 of ballast. In this case, we need to deballast at least 950 m3 of ballast and then refill it. Actually, we need to deballast as much as possible. 5% is just allowed for the unpumpable ballast.

Flow through method/ overflow method

The second method is to keep on ballasting the ballast tank and keep on overflowing the ballast water from ballast tank through air pipe or other openings of the ballast tank.

For the flow-through method, BWM convention regulation D1 requires to pump in 3 times of the ballast tank capacity to achieve 95% of the volumetric exchange.

Regulation D2. Ballast water performance standard

The first ballast water standard is temporary and ultimately all ships need to arrive at ballast water performance standard (regulation D-2). This second ballast water standard is more scientific .

It aims to control the number of actual species that can be discharged.

this can only be achieved by a Ballast water treatment system. This system is fitted before the ballast overboard and it treats the ballast water to the required standards before the ballast water goes overboard.

Discharge criteria

– Any type approved ballast water treatment system need to comply with the discharge criteria of regulation D2 and they are –

Capacity discharge for organisms;

1. Less than 10 organisms per m3, for organisms> 50 micrometers,
2. Less than 10 organisms per ml, for organisms between 10 and 50 micrometers

Capacity of indicator microbes; (the unit is  cfu – colony forming unit)

1. Toxigenic vibrio cholera: 1 cfu per 100 ml
2. Escherichia coli: 250 cfu per 100 ml
3. Intestinal enterococci: 100 cfu per 100 ml

Regulation B-1. Ballast water management plan (B1)

BWM convention, regulation B-1 requires the ships to have an approved Ballast water management plan. The ballast water management plan is a ship specific plan and has all the details related to the compliance with BWM convention.

For example, it lists which regulation is applicable to the vessel regulation D-1 or regulation D-2.

In the case of regulation D-1, the approved process of achieving 95% of volumetric exchange of ballast will be provided in the BWM plan. It would also contain the safety consideration for ballast water exchange.

For example the information about the set of ballast tanks that can be exchanged together along with the ship’s stability during this process.

If regulation D-2 is applicable then the BWM plan would contain the information about Ballast water treatment system. And the BWM plan provides information about the handling of sediments from the ballast water tanks.

Regulation B-2. Ballast water record book (B2)

BWM convention regulation B-2 requires the ships to have on board a “Ballast water record book”. An entry needs to be made for each activity related to the ballast water.

Below are the entries that need to be made

• Whenever Ballast Water is taken on board
• Whenever Ballast Water is circulated or treated for Ballast Water Management purposes
• When Ballast Water is discharged into the sea
• When Ballast Water is discharged to a reception facility
• Accidental or other exceptional uptake or discharges of Ballast Water
• additional operational procedure and general remarks   

Regulation B-3: Ballast water management for ships

Vessels need to comply with either regulation D-1 (Ballast exchange) or Regulation D-2 (Ballast water treatment system).

BWM convention regulation B-3 provides this information.

as per the revised regulation B-3

• New ships (built on or after 08 Sept 2017) must meet D-2 standards.
• Existing ships (built before 08 Sept 2017) must meet D-2 standards at their first IOPP renewal survey after 08 Sept 2019.
• All vessel must comply with D-2 standards before 08 Sept 2024.

Regulation B-4. Criteria for ballast water exchange

BWM convention regulation B-4 provides the criteria for deep sea where the ballast exchange needs to be carried.

And as per regulation B-4, the ballast water exchange need to be carried at

• 200 Nautical miles from nearest land in a minimum water depth of 200 meters.
• Where 200 NM is not possible, then as far as practicable from the nearest land but not less than 50 NM from nearest land and in a minimum water depth of 200 meters

Regulation B-4.3 also clarifies that the ship don’t need to deviate from the intended route for the purpose of complying with this requirement.

Regulation E-2. International Ballast water management certificate

BWM convention regulation E-2 requires that every ship that complies with the requirements of the conventions be issued with a certificate. The International Ballast water management certificate is issued after the successful initial survey of that vessel.

The initial survey is carried out to verify that

• the ship’s ballast water management plan complies with the requirements of the convention.
• The equipment and procedures comply with the requirements of the convention.

The ballast water management certificate is valid for 5 years.. It is subject to the annual surveys. The annual survey is carried out each year within three months before or after each anniversary date. Apart from that, an Intermediate survey is carried out within three months before or after the second or third-anniversary date of the certificate.

Ballast water exchange record needs some data, they are:

1. Date of the operation

1. Ship’s ballast tank used in the operation.
2. Temperature of the ballast water.
3. Salinity of the ballast water in PPM (salt content in parts per million).
4. Position of the ship (latitude and longitude).
5. Amount of ballast water involved in operation.
6. All the records entered must be signed by a responsible officer (normally chief officer).
7. Master is overall in-charge of the operation and he will also acknowledge the ballast/ de-ballast operation by signing the BMP log.
8. Date and identification of the tank last cleaned.
9. If there is accidental discharge of ballast exchange it must be entered and signed. Same information is to be given to concerned port state authority.