Wartsila has announced that it has received the final approval status from the International Maritime Organization's (IMO) Marine Environment Protection Committee (MEPC) for its Wartsila Aquarius EC ballast water management system. The approval was granted at the MEPC's 65th session held at the IMO headquarters in London on May 13. Basic approval had been granted in October 2012.

According to Wartsila, final approval is required for systems using an active substance, and is based upon examination of full scale prototype test data and all required supporting documentation on aspects such as risk and safety to the ship, crew, general public, and the environment.

The documented information was reviewed and approved by a joint panel of experts from the Scientific Aspects of Marine Environment Protection ballast water working group. The application was submitted to the IMO by the Dutch Human Environment and Transport Inspectorate. A key element of the final approval submission was an investigation covering the impact of treated ballast water on coated and uncoated materials. A full type approval certificate for the system is expected by end of July this year.

Ballast water treatment with an Wartsila Aquarius EC system is achieved through a two stage process. Upon uptake the sea water is first passed through a back washing filter (first stage) and then the filtered sea water passes through a static mixer, where the disinfectant generated from the side stream electrolysis unit (second stage) is injected to ensure a maximum level of 10 parts per million (ppm) in the treated ballast water.

During discharge the filter is bypassed and any residual oxidant in treated ballast water is monitored before being discharged overboard. If required, treated ballast water is neutralized by injecting sodium bisulfite into the main ballast line during discharge. Neutralization effectiveness is continuously monitored to ensure compliance with MARPOL discharge limits.

Wärtsilä offers the Aquarius EC and the Aquarius UV systems, which both became part of the portfolio following the acquisition of Hamworthy in January 2012.