Wärtsilä BWMS Granted USCG AMS Acceptance

The United States Coast Guard (USCG) has granted Alternate Management System (AMS) acceptance for Wärtsilä's Aquarius EC Ballast Water Management System (BWMS). This allows all US and foreign flag ships fitted with this system to operate in US territorial waters and to discharge treated ballast water for an interim period of up to five years from the ship specific implementation date.

AMS acceptance is the first stage towards obtaining full USCG type approval. Wärtsilä anticipates having all activities necessary to gain full US type approval completed within the five year interim period.

When ratified, the International Maritime Organization's (IMO) Ballast Water Management Convention will require the owners of up to 40,000 vessels worldwide to install a BWMS. However, the USCG has already implemented legislation requiring compliance with the regulations covering discharges from ships when sailing in US coastal waters. The intention of the legislation is to address the issue of invasive aquatic species being carried in the ballast water of ships and then discharged to the sea where they could possibly harm local species. The IMO ratification requires support from 35% of the world's merchant shipping tonnage. Japan and Turkey recently ratified the ballast water convention, meaning that contracting countries now represent 32.54%, just 2.5% short of the necessary tonnage. Ratification is, therefore, expected within the near future.

"With global BWMS regulations now imminent, ship owners must evaluate as a matter of some urgency the ballast water treatment technology best suited to their existing and future vessels. Our technical leadership in this field allows us to provide strong support to our customers in meeting their environmental compliance obligations," says Dr Joe Thomas, Ballast Water Treatment Director, Wärtsilä Ship Power.

Wärtsilä's Aquarius UV BWMS was earlier granted USCG AMS acceptance. Orders were recently received for 12 Aquarius UV systems to be installed in six new bulk carriers currently under construction in Japan. The AMS approval process for the Aquarius EC has taken longer than that of the UV system as it uses an active substance to treat the ballast water. The testing procedures are, therefore, more stringent.

Wärtsilä Aquarius EC

The Wärtsilä Aquarius EC BWMS uses a simple and efficient two-stage process involving filtration and electro-chlorination (EC). During uptake, seawater is first passed through a 40 micron backwashing screen filter to remove particulate, sediment, zooplankton and phytoplankton. Disinfection of the filtered sea water is then carried out using hypochlorite generated from the side stream EC process, and controlled by the BWMS control system. Upon discharge, the ballast water by-passes the filter and any residual active substance is neutralized using sodium bisulphite, to ensure that the ballast water is safe to discharge back to the sea in full compliance with MARPOL requirements.