Hamworthy developed a new oily-water separator that is cost-effective to install and operate. The new HS(M) range comprises three units offering capacities from 12 to 96m3/day, and a discharge quality that is guaranteed better than 5 ppm but typically better than 1 ppm. The HS(M) range uses side-stream cross-flow membrane technology. The development follows Hamworthy's experiences with this type of technology on the MBR grey and black water treatment plants in use on the UK Royal Navy’s Type-45 destroyers, and on cruise ships belonging to Princess Cruises, Radisson Seven Seas and Cunard.

The company stated that While the HS(M) system has a slightly higher initial capital cost than some filter systems, a side-stream cross-flow membrane system will show real savings within 18 months of operation because of the much lower operating costs. By the end of 25 years of service, filter systems will have cost up to five times as much as a comparable side-stream cross-flow membrane system. The HS(M) series have minimal maintenance requirements. The membrane life is guaranteed for five years with a life expectancy greater than 10 years. The units offer modular construction for newbuild vessels reducing shipyard installation times. In retrofit situations, the compact size facilitates transportation through typical ships' access routes, while 'bolt-on' design helps to reduce installation efforts.