To thwart invasive species, Mitsubishi Heavy Industries Ltd. unveiled a new device that removes living organisms from ships' ballast water at Yokohama Port's Honmoku Pier on April 5.

Ballast water refers to seawater pumped into tanks aboard a ship to serve as a weight that keeps it stabilized after unloading. Foreign organisms contained in ballast water are recognized as a threat to native ecosystems.

Mitsubishi's device comprises a 12-meter-long container--a standard size in freight transport--that houses filters to remove living organisms, an ultraviolet apparatus to sterilize bacteria, and other equipment. The container is designed to be installed as a whole in the hold of a ship.

The new device makes installation simpler and less time-consuming than traditional models that have to be installed in engine rooms. It also has the advantage of being mountable on ships that have little space for pipes and equipment in their engine rooms.

The ballast water processing device was developed jointly with shipping agent Mitsui O.S.K. Lines Ltd. The first unit of the new device will be mounted on a Mitsui O.S.K. Lines container ship for use starting in this spring.

The impact of ballast water on ecosystems emerged as an issue of global concern in the late 1980s. The International Maritime Organization adopted a convention in 2004 to oblige cross-border ship operators to process ballast water until its content of living organisms falls below a given limit.

While the convention has yet to take effect, manufacturers in Japan and abroad are competing to develop ballast water processing devices in anticipation of it eventually being implemented.

Source: The Asahi Shimbun