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What Is Ballast Water Treatment?

types of ballast water treatment infographic

Individuals in the shipping industry carry great responsibility each time they leave port. Firstly, they have a responsibility in carrying out their duties, transporting cargo, and delivering goods for clients across the globe. Completing this task is essential — and it requires each part of every ship to be in perfect working order. Secondly, shipping companies must consider the ecological impact of their transport vessels. Global shipping channels have connected humanity at an unprecedented scale, but it is also put the various ecosystems around the world at risk. This is due to microorganisms that travel in the ship’s ballast water and can contaminate or invade the marine ecology of a new region, causing untold damage to the area.

In response to these ecological risks, the International Marine Organization (IMO) adopted the International Convention for the Control and Management of Ships’ Ballast Water and Sediments in 2004. This Convention aimed to halt the spread of invasive aquatic species by implementing requirements on the shipping industry to treat their ballast water.

A high-quality ballast water management system is critical for the success of any shipping business. But how do these systems work, and how do they add value to your ships? This article will discuss the immense impact that ballast water treatment can have on your business.

Why Do You Need Ballast Water Treatment?

The aim of ballast water treatment is the elimination of invasive marine species. The USDA reports that ballast water is “one of the major pathways for the introduction of non-indigenous marine species.”

When ships release ballast water at a new port-of-call, they risk introducing alien species, from small fish to microorganisms, into the water around the new area. This can result in a variety of harmful effects; the European Maritime Safety Agency credit invasive marine species with microbial exposure, lower habitat quality, and other dangers that can ultimately harm fishing and even protected species in the region.

To prevent these damaging effects, the United States Coast Guard (USCG) and the International Maritime Organization (IMO and USCG) require all ships to “undertake comprehensive actions in order to prevent, reduce and, if possible, eliminate the transfer of harmful aquatic organisms and pathogens through the control and management of ships’ ballast water and sediments.” This includes meeting the requirements of either Ballast Water Management D-1, a regulation that requires any ship performing ballast water exchange to do so with an efficiency of 95% ballast water, or Ballast Water Management D-2, a regulation that sets a maximum concentration of microorganisms in discharged ballast water. The standards for regulation D-2 are:

  • < 10 viable cells per m3 for plankton smaller than 50 μm
  • < 10 viable cells per mL for plankton between 10-50 μm
  • < 10 Colony Forming Unit per 100 mL for Toxicogenic Vibrio Cholerae
  • < 250 Colony Forming Unit per 100 mL for Escherichia Coli
  • < 100 Colony Forming Unit per 100 mL for Intestinal Enterococci

A properly designed BWMS will meet these standards automatically, eliminating the shipping operator’s need to worry about these regulations.

How Ballast Water Treatment Works

It should be noted that the majority of BWTS use a combination of filtration and a secondary, disinfection stage for treatment.

Chemical Disinfection

Many BWMS utilize biocides as their disinfection stage. Biocides, which in BWMS typically use chlorine as an  oxidizing disinfectants inactivates microorganisms in the ballast water. The main drawback of biocides, which are used in about half of all systems, is that the treated water may still need to be neutralized or detoxified before its final deballasting.

U.V. Treatment

Some ballast water treatment systems use ultraviolet lamps. As the ballast water passes through chambers that contain the lamps, the ultraviolet light impacts the DNA of the organisms and renders them non-viable, or incapable of reproduction. This effectively eliminates the threat of microorganisms from thriving in the water and prevents them from becoming a burden on the ecosystem where they are released. However, UV can be affected by waters with low TSS (total suspended solids), and its success depends largely on the quality of the filtration system that precedes the treatment.

Deoxygenation

Like biocides, deoxygenation kills any living organisms in the ballast water. The ballast water treatment system injects an inert gas (such as nitrogen) into the tank or the ballast flow to asphyxiate the organisms. This system can be effective, but it is important to note that this process takes two to four days and requires the tanks to be sealed against atmospheric oxygen. Deoxygenation is not recommended for short transits.

Heat Treatment

As the name suggests, heat treatment involves heating ballast water until it kills any organisms in the water. There are two main ways to complete this method: heating the ballast water in their tanks or heating the water by running it past the ship’s engines (effectively turning it into cooling water). Heat treatment will disinfect the ballast water and make it suitable for release, but this can take a long time – and the heat can cause greater corrosion in the ballast water tanks.

Ultrasonic Treatment

Ultrasonic treatment (also called cavitation treatment) uses high energy ultrasound to eliminate organisms in the ballast water. The high pressure caused by the ultrasound ultimately breaks down organisms’ cell walls, killing them. Ultrasonic treatment is an attractive choice because it is low maintenance and non-chemical; however, research indicates that this ballast water treatment system works best in conjunction with other treatment methods like U.V. or biocides.

Almost every ballast water treatment system uses a water filter in conjunction with another method, such as the ones discussed above. The right water filter serves several practical and economic purposes in the BWTS. First, it is an effective way to remove sediment that can be taken in at turbulent ports and if not properly removed, can collect in the ballast tanks. Additionally, a filter can remove a large portion of the microorganisms that we have already discussed. This reduces the time and energy needed to neutralize the organisms that make their way through the filter and need to be treated before the water they reside in can be stored onboard or dumped.

Your Ballast Water Treatment System

The type of ballast water treatment system your ship needs will vary based on size, available space, budget, and more. However, it is almost certain that your ship (any ship, for that matter) will benefit from a ballast water treatment system that incorporates a Filtersafe filter.

Filtersafe offers specialized solutions that perfectly compliment every ballast water treatment system. Firstly, our patented filtration screen does not only keep out most zooplankton, phytoplankton, and sediment from entering the ballast water tanks. Since the screens have proven filtration capabilities down to 25 microns, the effluent water needs less secondary treatments to sterilize the water, saving BWTS owners money through lower power consumption and use of disinfection chemicals.

Next, all E-Series ballast water filters are capable of being installed horizontally or vertically and rotated to any position, even after the filter has been delivered to the vessel. This flexible modular design allows Filtersafe to build and ship their filters faster than any other company in the market.

Lastly, the various different models of filters have been optimized to handle low or high water flows, so whether you have a large oil tanker with cavernous ballast tanks, or a simple cargo ship on short, coastal voyages, you can turn to Filtersafe to provide filters for all of the vessels in your shipyard.

Filtersafe has been an industry innovator for ballast water treatment systems for over 15 years – and today, our products filter about 25% of the world’s ballast water. To learn more about our ballast water treatment systems (or to find a filtration system that suits your ships), contact our team of specialists today.