As legislation becomes stricter on what can be discharged from ships into the ocean, shipboard water treatment technology has had to develop to meet these requirements. In the past a simple discharge pipe was all that was required; now most ships have a water treatment system for processing all the wastewater onboard. Bauer BF Series geared motors are specified for many shipboard water treatment systems because of their reputation for reliability, even in harsh marine conditions.
Most ships generate four different types of wastewater: blackwater, which is waste from toilets; greywater, which is waste from bathing and laundry; kitchen wastewater, which is contaminated with food, other liquids and cooking oils; and bilge water, which is contaminated with fuel and engine oil. In the past a discharge pipe would have sent all of the water, untreated, into the ocean. However, as awareness of our environmental responsibilities has developed, international regulations are now in place which ensure that water is treated prior to discharge.
Traditional shipboard water treatment involved biologically cleaning the blackwater separately, prior to adding it to the greywater and kitchen water. This mixture was then disinfected and finally discharged. The bilge water was treated entirely separately, passing through an oil separator and then discharged. Having to treat the different wastewaters separately is extremely inefficient in terms of space, which is already limited on most ships. These limitations can cause problems on vessels with a large number of passengers, as several hundred thousand litres of water may need to be processed each day.
To reduce the footprint of the water treatment systems, a single reactor system has been developed which can treat the blackwater, greywater, kitchen wastewater and degreased bilge water together. The reliability of this system is paramount. If it fails the ship can no longer process the wastewater and the reservoir tanks may fill which could in turn affect the availability of clean water. Operating in a marine environment, the water treatment system is subjected to corrosive sea air, as well as turbulent conditions which may result in contact with salt water. 
Bauer Gear Motor, part of Altra Industrial Motion, supplies its BF Series of geared motor drives for single reactor systems designed for shipboard water treatment. Each shipboard treatment plant includes two perforated screen systems which are driven by the Bauer geared motors. The systems have been specified on many large ships around the world, including cruise ships which can have as many as 3,000 people onboard.
The BF series complies with many international standards which certify it as suitable for use in marine applications. It features a corrosion protected, high-tensile, cast iron housing which is available with up to IP66 protection thanks to its seals. A hardened wear sleeve and spray ring at the rotor seals further reduces the risks of leaks while ensuring reliable lubrication. The design uses low noise gearing, which improves working environments while also increasing efficiency, and has a maximum torque rating of 18,500Nm.