What you need to know about Ballast Water Treatment requirements onboard vessels

Water has been used as ballast to stabilize ships at sea ever since steel-hulled vessels came into widespread usage. In order to keep the operational conditions of the ship at a safe level throughout a journey, ballast water is pumped in. This method decreases the amount of stress placed on the hull, provides transverse stability, enhances propulsion and maneuverability, and compensates for changes in weight brought on by varying levels of cargo load as well as consumption of fuel and water.

In spite of the fact that ballast water is necessary for the safe and effective functioning of modern shipping operations, it has the potential to create significant issues for the environment, the economy, and human health due to the large number of marine species that are transported in it. Bacteria, microorganisms, small invertebrates, eggs, cysts, and larvae of a variety of species are all included in this category. There is a chance that the transferred species will be able to establish a reproductive population in the new environment. If this happens, the species will likely become invasive, which means that it will outcompete the original species and eventually become a nuisance.

In 2004, the International Marine Organization (IMO) approved the International Convention for the Control and Management of Ships’ Ballast Water and Sediments as a means of mitigating the adverse effects of these ecological threats. This Convention attempted to put an end to the spread of aquatic invasive species by imposing regulations on the shipping sector that required them to treat the ballast water carried on their ships. Please follow the link if you want to learn more about IMO Convention and Codes. The course is free and you just need to subscribe.

Any shipping company needs to invest in a ballast water management system of the highest possible caliber. But how exactly do these systems function, and why exactly are they beneficial to your ships? In the following paragraphs, we will examine the significant influence that the treatment of ballast water can have on your ballast system.

There are three approaches to treating ballast water; mechanical, physical or chemical. Mechanical methods would include separation and filtration; physical methods include ozone, electrical currents, or UV radiation, while chemical solutions are biocides or a form of chlorination.

There are so may articles and documentation available online which explains how different types of ballast treatment systems works and every each of you will encounter more or less of these types during your sea time. It is important to know that the systems usually comprises of a combination of methods mentioned above. Here there is a short overview of different technologies:

      • Filter and UV – Before subjecting the water to UV sterilization, these systems first remove larger organisms and particulate matter. In most cases, filters will perform a back flush on their own whenever a certain differential pressure is surpassed. The organisms are killed or rendered inactive by the UV light because it causes damage to their DNA, which prevents them from carrying out essential cellular tasks. The ocean water is subjected to filtration and UV treatment before being used for ballasting; after being used, the water is subjected to a second round of UV treatment.
        These systems do not produce any byproducts that are hazardous to the environment, and they are not affected by the temperature or the salinity of the water. If the saltwater has a low UV transmittance, then an increased amount of energy will be required to achieve the same UV goal dose.
      • Filter and Electrolysis – These systems filter the particulates and the bigger organisms before active substances generated from the electrolysis are injected into the ballast water. The electrolysis can be installed inline or in a side stream, where the disinfectant breaks down the cell membranes of the organism. Some system uses a higher dose of active substance without filter.
        The active substances are produced through oxidation of seawater in the electrolysis chamber. Electrolysis also produces hydrogen gas which shall be correctly handled for safety of the ship. During ballasting, the seawater is filtered, and active substances are injected. During de-ballasting, the active substance is neutralized prior to discharge overboard.
      • Chemical injection – These systems are frequently utilized in conjunction with filtration, however this is not always the case. In order to ensure that the ballast water is disinfected, a chemical solution is injected into it. Before the disinfectant may be discharged overboard, it will first need to be neutralized, regardless of whether it is in liquid or granular form.The chemicals that are utilized have trademarks, and delivery may be restricted to particular ports. Because of the potential danger posed by the chemicals, they must be kept on board in airtight containers. When working with chemicals, it is necessary to have well-trained crews and adhere to stringent safety regulations. When compared to alternative ballast water technologies, these BWMS have a significantly higher cost of operation.
      • Ozone – These systems sterilize by injecting O3, which is produced from the surrounding air. Through its reaction with seawater, oxygen 3 oxidizes and neutralizes aquatic species, thereby contributing to the production of effective disinfectants. Although temperature and salinity are not obvious factors affecting the efficiency of these BWMS, a longer holding time may be necessary in some cases. Prior to discharge, residual by-products are required to have their acidity neutralized. Because ozone is toxic, there must be additional precautions taken, and the crew must undergo training.

As you may be aware each vessel must carry an approved Ballast Management Plan. The Ballast Water Management Plan (BWMP) is the document that details the procedure for the discharge of ballast water and the handling of sediment in accordance with regulation D-1 (exchange), and/or regulation D-2 (treatment), and regulation B-5 (sediment management). Conducting ballast water discharge and the cleaning of sediments in accordance with the BWMP ensures compliance with regulations D-1 or D-2, and B-5.

The D-2 standard becomes mandatory for all existing vessels at completion of the first IOPP renewal on or after 8 September 2019. Vessels keel-laid or having underwent a major conversion after 8 September 2017 (EIF date) shall comply with the regulation D-2 upon delivery.

In case of system malfunction the vessel must contact the port authority and flag state administration immediately to discuss contingency measures as per  IMO guidance circular on contingency measures BWM.2/Circ.62 (see attachment below).

The IMO has established a generic guidance in BWM.2/Circ.62 for situations where ballast water to be discharged from a ship is determined to be non-compliant. In such cases, communication between the ship and the port state should occur. The ship and the port state should consider the following as possible contingency measures on a case-by-case basis:

      • Actions predetermined in the BWMP of the ship
      • Discharging ballast water to another ship or an appropriate shipboard or land-based reception facility, if available
      • Managing the ballast water or a portion of it in accordance with a method acceptable to the port state
      • Operational actions,such as modifying sailing or ballast water discharge schedules, internal transfer or ballast water other retention of ballast water on board the ship. The port state and the ship should consider any safety issues and avoid possible undue delays.

Having considered all options above, the ballast water may be discharged in the port or any suitable area, as acceptable to the port state. Port state consideration may include environmental, safety, operational and logistical implications of allowing or disallowing the discharge.

Exchange may be offered as a contingency measure but cannot be performed without permission from the port authority and flag state. The vessel must obtain approval of the exchange method before proposing exchange as a contingency measure.

The discharge of ballast water is subject to any conditions of the port state. In any case, the ship is required to do its best to correct the malfunction of the BWTS as soon as possible and submit its repair plan to the PSC authorities and the flag state.

Some countries, such as the Ukraine and the USA, have stricter requirements than those listed in the convention, therefore it is recommended to familiarize with local requirements prior to conducting discharge of the ballast water in a new port.

When travelling in US waters, the USCG requires that the BWMP contain vessel-specific contingency methods. The BWMP should also include procedures for contacting the Captain of the Port (COTP) and reporting to the National Ballast Information Clearinghouse (NBIC) in the event of a BWTS malfunction. The vessel must contact US authorities as soon as possible and ask for instructions. US regulations require that the vessel inform the nearest COTP, but it is recommended that the destination COTP also be informed. The vessel must have or obtain D-1 certification before proposing exchange as a contingency measure. More information on contingency measures in the USA can be found in the attachment below.

When it comes to any limitations or local prohibitions for chemical treatment systems, it is important to know that the type approval process covers the possibility of toxic discharge according to the IMO and/or USCG standards. Chemical treatment systems are required to satisfy minimum toxicity requirements like all BWTSs.

The requirements related to toxic discharge for different US states are addressed in the 2013 VGP and the US EPA’s Generic Protocol for the Verification of Ballast Water Treatment Technology, known as the ETV Protocol.

The contingency measures chapter is required in the BWMP if the administration of the vessel has decided to implement it or if desired by the owner. In case of BWTS malfunction, well-planned BWM contingency measures allow ship owners to avoid unnecessary downtime for the vessel. The port authority of destination and the flag administration are usually to be informed about the malfunction of the BWTS.

With regard to the query if the vessel can bypass the system during cargo operations in a challenging water port, although the BWTS is fully operational or in the high seas after leaving the challenging port of operation it is important to mention that Ballast Water Management Convention does not allow any bypass unless this is an emergency situation for the vessel.

In case the treatment system cannot be used for ballasting operations due to filter clogging, and there is untreated ballast water in the tanks, contingency measures must be discussed and agreed upon with the port state of destination where the ballast water is planned to be discharged.

Similarly, in case ballasting operations were carried out with alarms indicating that the treatment system is operating outside the system’s performance claim (e.g. UV intensity or TRO is too low), the treated ballast water may not comply with the D-2 standard, and contingency measures must be discussed and agreed upon with the port state of destination where the ballast water is planned to be discharged.

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Source, Credit and Bibliography:

    • DNV Rules and Regulations
    • Youtube video training credit – Marine Online
    • Header picture – Alfa Laval

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