Press Information

Final Approval of G9 for Coagulation and Magnetic Separation Technology,
Hitachi Ballast Water Purification System (ClearBallast), granted by IMO

Hitachi Plant Technologies, Ltd.
Mitsubishi Heavy Industries, Ltd.

Tokyo, Japan, July 21, 2009 - Hitachi Plant Technologies, Ltd. and Mitsubishi Heavy Industries, Ltd. were granted final approval by the IMO*1 for their jointly-developed Hitachi Ballast Water Purification System (ClearBallast) in accordance with the Procedure for approval of ballast water management systems that make use of Active Substances (G9)*2 on July 17, 2009, becoming the first Japanese companies which receive such approval.

In preparation for type approval*3 from the Ministry of Land, Infrastructure, Transport and Tourism of Japan, furthermore, the companies have performed land-based testing at Tokyo Bay using an actual-scale equipment and shipboard testing using a test equipment installed on an LPG tanker (capacity: 78,500 m3, built at Nagasaki Shipyard and Machinery Works of Mitsubishi Heavy Industries, Ltd.) owned by Yuyo Steamship Co., Ltd.. These tests were carried out in parallel and both cleared the Ballast Water Performance Standard regulated in the International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004, known as D-2 standard *4.

Going forward, Hitachi Plant Technologies and Mitsubishi Heavy Industries plan to complete the administrative procedures required for type approval and to actively engage in sales activities with the aim of securing orders for 100 units in FY2012.
  • *1 IMO: International Maritime Organization
  • *2 Procedure for approval of ballast water management systems that make use of Active Substances (G9): A standard employed by the IMO to determine the environmental safety of active substances used in ballast-water management systems. The IMO reviews and gives a basic approval for use of said active substances based on evaluation of any associated hazards and evaluation of the environmental effect of water treatment using prototype equipment; furthermore, final approval is given by the organization based on evaluation of the environmental effect of water treatment using land-based actual equipment.
  • *3 Type Approval: A process whereby the authorities in individual countries examine the performance of ballast-water management systems and give approval based on the guidelines set forth in the International Convention for the Control and Management of Ships' Ballast Water and Sediments. As a precondition, land-based and shipboard testing must have been passed and G9 final approval must have been granted.
  • *4 Ballast Water Performance Standard regulated in the International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004, known as D-2 standard:



Microorganism greater than 50 μm Note 1

Less than 10 microorganisms/1 m3

Microorganism from 10 to 50 μm Note 1

Less than 10 microorganisms/1 ml

Toxicogenic Vibrio Cholerae (O1, O139)

Less than 1 cfu Note 2/100 ml

Escherichia coli

Less than 250 cfu Note 2/100 ml

Intestinal Enterococci

Less than 100 cfu Note 2/100 ml

Note 1: Minimum Dimension
Note 2: cfu = colony forming unit
Shipboard Testing Equipment
LPG Tanker with Shipboard Testing Equipment
Land-based Testing Equipment


Outline of Hitachi Ballast Water Purification System (ClearBallast)
Used as ballast for stabilizing hull balance, ballast water usually contains plankton, bacteria, mud, and sand specific to the port from which it was drawn. Most of this ballast water is, however, discharged at a different port, and as such, the organisms, bacteria, and other materials contained within it can cause serious environmental damage to the local ecosystem.


As a means of eliminating this type of problem, the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (otherwise known as the Convention of Ballast Water Management) was adopted at an international conference of the IMO in February, 2004. The convention requires that the D-2 standard be applied in a stepwise manner to ships undertaking international voyages in line with the year of building and the ballast tank capacity, with all ships required to adopt the standard by 2017. In line with these requirements, there is now a need for ships to be fitted with ballast water management systems. 

Hitachi Ballast Water Purification System (ClearBallast) applies the type of coagulation technology typically used at water purification plants to remove plankton and bacteria in combination with magnetic separation technology developed for the removal of algae from lakes and rivers. In contrast to biocide approaches, the coagulation method does not use chlorine, ozone, ultraviolet light, or other disinfectants, and therefore, the risk of residual chemicals causing secondary contamination is removed. Furthermore, this process leads to the flocculation of small particles, and the resultant flocs can be removed using relatively coarse filters with comparison to direct filtration approach. Due to this approach, it was possible to make equipment compact and rapid treatment of ballast water.

In order to ensure that such a purification equipment could be installed on ships and could then operate as part of a fully integrated system, it needed to be optimized in line with advanced ship outfitting design. Focusing their collective expertise and experience, Hitachi Plant Technologies and Mitsubishi Heavy Industries conducted joint research in order to develop and commercialize this product, and were ultimately successful in realizing an equipment suitable for on-board use.

  • (1) Enhanced biological,environmental, and maritime safety
    • 1. Even organisms growing in an environment consisting only of water treated by this system show no signs of inhibited growth or deformities. (Confirmed through organism toxicity testing*5.
    • 2. Requiring no use of disinfectants, the system poses no threat of secondary contamination from residual chemicals.
    • 3. The system has no adverse effect on paint or other coatings within the ballast tank.
      (Confirmed through corrosion assessment testing.)
    The above benefits demonstrate how the new system can help to enhance biological, environmental, and maritime safety.
    *5 Organism Toxicity Tests: Set forth by OECD, the Organisation for Economic Co-operation and Development, this testing was carried out using skeletonema (an algae), apohyale barbicornis (an invertebrate), and oryzias javanicus (a fish) raised in treated water.
  • (2) Reduced mud buildup inside ballast tanks
    Capable not only of eliminating plankton, bacteria, and the like from sea water, the system can also remove sand, mud, and other suspended solids originating from the sea bed. In addition, it can prevent the build up of mud consisting of dead organisms within the ballast tanks.
  • (3) Suppression of the breeding of bacteria and algae inside ballast tanks
    In addition to limiting the ability of bacteria contained within mud to multiply, this system can also remove phosphorus – an essential element for aquatic life. In the event, therefore, that a part of algae get drawn into ballast tanks as a result of the occurrence of a crimson tide, for example, the system is highly effective in suppressing the subsequent multiplying of this algae.
  • (4) Full line-up including explosion-proof specifications
    Special versions of the system have also been designed to prevent explosion, making them highly suitable for use in oil tankers, liquefied gas tankers, container ships carrying hazardous cargo, chemical tankers, and the like.
  • (5) Efficient power usage
    At 13 kW for 200 m3/h or 76 kW for 1,600 m3/h of ballast water processing capacity, the system's power consumption is relatively low, and as extra power-generation capacity may not necessarily be needed, the effect on the ship's body can be minimized.
  • (6) No effect on loading procedures
    The system treats ballast water during intake, not discharge; accordingly, no modification is needed to the existing procedures used during the loading of cargo.
Operation Sequence
  • (1) During the intake of ballast water, coagulants and magnetic powder are added in coagulation and flocculation tanks. The water is then mixed, causing plankton, bacteria, mud, and other contained substances to form magnetic flocs of about 1 mm in diameter.
  • (2) When then passed through a magnetic separator, the flocs adhere to magnetic disks and are removed. Finally, the treated water is filtered in a filter separator, before being pumped into the ballast tanks.


System Specifications


Ballast Pump

Capacity (m3/h)



Electric Power (kW)


Modular Type Purification System

20 Foot Container



20 Foot Container x 2

(40 Foot Container x 1)


L8.4 m x W2.7 m x H3.5 m


Unit Assembling Purification System

- Coagulation tank

- Flocculation tank

- Magnetic separator

- Filter separator

- Coagulant supply device

- Control panel

40 m2 Foot Print Note 3



58 m2 Foot Print Note 3 

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