Ballast Water Management

Ships need to carry ballast water for stability purposes, and to correct any problem in list, trim, etc. Many species of bacteria, plants, and animals can survive in the ballast water tanks and the sediments carried in ships, even after journeys of several months duration. When these waters are discharged during subsequent loading and discharging operations in the waters of other countries, it may result in the establishment of harmful aquatic organisms and pathogens which pose threats to indigenous human, animal, and plant life and, as a whole, to the marine environment.

This potential of the ballast water to cause harm has been recognized by the World Health Organization, which is worried about the role of ballast water in the spreading of epidemic diseases. This is especially true of ballast taken from developing countries, where hardly any sewage treatment is done and raw sewage as well as industrial wastes find their ways into the seas. Thus, in the view of all these threats, a ballast water management plan has become compulsory on all ships trading worldwide.

This material also is helpful in Chief Engineer license exams or MEO Class I ( Marine Engineer Officer Class I) in India.

In the preparation of the ballast water management plan the following significant factors should be considered:

• Near coastal organisms released in open seas or mid-ocean do not survive generally, and vice versa.
• Chemical treatment can kill organisms in ballast water. So chemical dosing in ballast tanks is one method.
• Fresh water organisms do not survive in salt water, and vice versa.
• Ballast water over one hundred days old is in a low risk category, as the absence of light, nutrients, and oxygen in the Ballast tanks generally kill the micro-organisms.
• For ships on short voyages and unable to do any ballast water exchange, discharge to reception facilities on shore is another solution.
• New emerging methods like thermal methods, filtration, disinfection, and ultra violet treatment can be considered.
• Ballast water intake should be avoided in the dark or at nighttime as the bottom dwelling organisms rise to the top.
• Ballast water intake should be avoided in shallow water and where the propellers can stir up sediment.
• Ballast water intake should be avoided near sewage and industrial waste outfalls.
• Ballast water intake should be avoided when and where phytoplankton bloom occurs.Ballast intake should be avoided where there is a known outbreak of diseases communicable through ballast water.

Thus before entering into the waters of any coastal state, ballast water exchange has to be done in mid-ocean or at least 200 nautical miles from shore and at a location where the water depth is at least 200 meters or more. There are three different methods of ballast water exchange:

• Sequential: In this method the ballast tanks are emptied until the ballast pumps lose suction and then the tanks are further stripped by eductor systems. This is followed by taking fresh ballast into the tank.
• Flow through method: In this method water in pumped into the tank and to allow it to overflow through the air vent or dedicated overflow vents. Three times the volume of the tank is to be pumped through to get a 95 percent efficiency of exchange.
• Dilution Method: In this method the tank has two openings; water is pumped in from one opening and flows out through the other.

A ballast water management plan stating the relevant International rules and regulations, and duties of personnel and operational procedures should be on board. Also it should mention which method of ballast water exchange is used on board.

When the requirement of ballast water exchange as per the requirements of a coastal state cannot be carried out, then the coastal state authorities should be informed before entering their coastal waters.

A responsible officer has to be designated to look after the operational parts. The Master of the vessel (also known as the Captain of the ship) is overall in charge, whereas the Chief Officer is the operational in charge and responsible officer.

Records of the ballast water exchange are to be entered in the ballast water record book by the responsible officer. The records should contain at the minimum the following information:

• Date
• Geographical location of the ship
• Ship’s tank or Cargo holds used
• Ballast water temperature
• Salinity of ballast water
• Amount of Ballast water loaded or discharged

The location and suitable access points for taking ballast water samples by Port Authorities should be identified in the ballast water management plan. The sampling points should be marked clearly for identification.

Routine cleaning of ballast tanks to remove sediments should be carried out in Dry Dock or in mid-ocean as per the ballast water management plan. All unnecessary discharge of ballast water should be avoided, where possible.