Open Loop Scrubbers on Ships under the Spotlight in new German Sudy
A new study points to the risks of polluting discharges arising from vessels as a result of new Sulphur emissions directive. In a response to the EU Sulphur Directive that came into effect at the beginning of 2015 in the North Sea and Channel region, shipping companies have been looking at ways to reduce the Sulphur based emissions from heavy fuel oil that have traditionally been burnt by ships. The new directive requires ships operating in the Baltic Sea, the North Sea and the English Channel to use marine fuel with a maximum sulphur content of 0.1% now.
One option being used by many shipping companies is the option to attach Scrubber systems to ships chimney exhausts. The scrubber helps clean Sulphur from the ships’ exhaust, can be used as an alternative to switching to a cleaner, more expensive fuel such as LNG which requires a completely new vessel. However, scrubbers can be of so called open and closed loop systems. The open loop is cheaper as it results in a wastewater discharge into the sea after the scrubber procedure is complete. A number of ports though are looking at investment in closed loop scrubber systems and the possible recycling of waste water and alkaline/acidic materials used to clean the Sulphur from the vessels exhausts.
The study advocates a common EU approach because many safety requirements are inscribed in EU laws, including the Water Framework Directive and the Birds and Habitats Directives. In the longer term, the researchers recommended regulating the discharge of scrubber effluents within the framework of the International Maritime Organization (IMO) to avoid putting EU ports at a competitive disadvantage. Whilst the study favours the use of clean liquid (diesel) and gas (LNG) to an exhaust gas after treatment for the purpose of Sulphur reduction it does recognise that their could be a role for closed loop environmentally friendly scrubbers in future.