Water Treatment – Reverse Osmosis (RO)

Frequently Asked Questions (FAQ): Reverse Osmosis Water Makers for Offshore Rigs

1. What is reverse osmosis and how does it differ from osmosis?
Osmosis is a natural process where water moves from a low to high concentration of solutes through a semipermeable membrane. Reverse osmosis reverses this process by applying pressure to force water from a high concentration to a low one, removing impurities and producing clean water.

2. How does a reverse osmosis water maker work on offshore rigs?
Seawater is drawn from the seawater ring main and passed through a pre-filtration system to remove suspended solids. The filtered water is then pressurized through membranes, separating pure water (permeate) from concentrated brine.

3. What happens to the freshwater after it's produced?
The freshwater passes through a remineralisation column, which helps stabilize the pH level and improves taste by adding essential minerals before it is stored or distributed.

4. What is the typical water recovery rate in RO systems?
A standard reverse osmosis system has a recovery rate of around 40%, meaning 40% of the feedwater is converted into usable freshwater while the remaining 60% is discharged as brine.

5. Can RO systems be customized for specific offshore requirements?
Yes, RO systems can be customized based on your specific requirements, including capacity, feedwater quality, available space, power supply, and operational conditions.

6. What are the standard specifications of your RO water makers?
Standard models typically produce between 45 to 82 m³ of freshwater per day, operate with feedwater salinity up to 42,000 ppm, and are skid-mounted with robust, corrosion-resistant frames and high-quality components.

7. What kind of filtration is used before the RO process?
A dual cartridge filter skid is commonly used for pre-filtration. In cases where the seawater source lacks sufficient pressure, a booster pump may be added to ensure stable operation.

8. Why are RO systems essential for offshore applications?
Offshore platforms and rigs do not have access to natural freshwater sources. RO water makers ensure a continuous, reliable supply of clean water, reducing dependency on water deliveries and supporting crew health and safety.