Wärtsilä Reverse Osmosis

Wärtsilä Reverse Osmosis is a water purification technology that uses a semi-permeable membrane to remove salts and ions from seawater to provide fresh water. Customers are now able to source both RO and Evaporator systems from the same supplier, while the two technologies can be combined into a Wärtsilä developed Smart Fresh Water Generation System to secure a cost-effective and fully automatic solution.

The Wärtsilä RO systems deliver between 10 and 1500 m3 per day of fresh water. They feature a modular and flexible design, and are customised to meet the operational and space requirements of the vessel. The system is applicable to virtually all vessel types.

    • Capacity 10 – 1500 t/d
    • Single and two pass design
    • Steady production of fresh water at a wide sea water temperature range between 0 - 35°C
    • Full-automatic or semi-automatic operation
    • Standard automation: Siemens S7-1500, Profinet or other by request
    • Easy connection to the Ship Automation and Control System
    • UV steriliser after prefiltration to reduce chemical consumption
    • Low energy consumption
    • Easy operation and maintenance
    • Flexible design according to the requirements and space
    • Different materials can be selected for components and piping
    • Modular design for retrofit projects and limited space
    • Suppliers of critical components can be selected (membranes, high pressure pumps, energy recovering devices, automation)
    • All proven suppliers from Western Europe and US
    • Support at design and installation stages
    • Less chemical consumption
    Spare parts and service

    Please send the vessel name, equipment type, serial number (if known), your company details and spares and/or service requirements to wsc.aftersales@wartsila.com and we will respond as soon as possible.

    Principles of operation

    Reverse Osmosis uses a semi-permeable membrane to remove salts and ions from seawater to provide fresh water. Semi-permeable membrane is a porous sheet barrier, which blocks the flow of salts and other solutes but allows only water to flow through.

    Seawater under pressure, is forced through microscopic pores in the membrane while larger dissolved solids and heavy molecular weight contaminants are continually flushed away as reject water.

    Main components

    1. Prefiltration (multimedia filters, self-cleaning filters, ultrafiltration)
    2. UV Sterliser
    3. High pressure pump
    4. Energy recovery system
    5. CIP/Automatic flushing system
    6. Reverse Osmosis Membranes


    1. Post-treatment (remineralisation)
    2. Remote monitoring system
    3. Flow transmitters: sea water, permeate, brine
    4. Super Duplex

    Related products

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