A series of eight new 33,000 DWT chemical tankers, currently under construction in Asia, will feature Wärtsilä Aquarius UV Ballast Water Management Systems (BWMS) each of which is certified for explosion proof (EX) requirements. This means that the BWMS units can be installed in Zone 1 hazardous areas. It is an International Maritime Organization (IMO) requirement that the BWMS for ships having hazardous areas on board must be EX-proof certified. This contract, which was signed in January, is the first EX-system delivery since the Wärtsilä Aquarius UV system was granted EX-certification in spring 2014.

Each of the eight vessels will have two Wärtsilä Aquarius UV systems installed. The particulars of this design required a partnership approach with the shipyard in order to successfully integrate the BWMS into the hazardous area, with the addition of deepwell pumps already delivered.

Wärtsilä has taken a systems approach to the EX validation process and the complete Aquarius UV BWMS module, rather than just the electrical components, is EX-certified. This approach improves accessibility, since the modular design allows some system components to be located outside the hazardous area, thereby increasing the availability and maintainability of the entire system.

“This first contract for our EX-certified BWMS represents yet another milestone contract for Wärtsilä. Knowing that the entire system module is explosion proof when installed within hazardous areas provides the peace of mind that alternative systems, where only the electrical components are certified, cannot. With IMO ratification expected very soon, we anticipate that the Wärtsilä BWMS range will be very much in demand,” says Dr. Joe Thomas, Director, Ballast Water Management Systems, Wärtsilä Ship Power.

Ratification of the IMO’s Ballast Water Convention is expected within the next few months and will require the owners of up to 40,000 vessels worldwide to install a BWMS. Although this ratification has yet to be finalised, the US Coast Guard (USCG) has already implemented its own legislation. This states that all ships will have to be in compliance with the regulations 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 can harm local species. Wärtsilä’s Aquarius UV systems have been type approved for the IMO regulations.

<strong>The Wärtsilä Aquarius UV BWMS</strong>

The Wärtsilä Aquarius UV BWMS uses a simple two stage process involving filtration and UV irradiation. During uptake, seawater is first passed through a 40 micron backwashing screen to remove particulate, sediment, zooplankton and phytoplankton. Disinfection of the filtered sea water is then carried out using medium pressure UV lamps, and controlled by the BWMS control system. Upon discharge, the filter is by-passed but the ballast water is again disinfected with UV treatment before safe discharge back into the sea. There are 13 distinct Wärtsilä Aquarius UV BWMS standard modules available with capacities ranging from 50 m3/h to 1000 m3/h.