Waterguide - Seawater
What is seawater?
Approximately 71 % of the Earth’s surface consists of water, of which 97.4 % is seawater and just 2.6 % is fresh water. This means that the sea is the largest habitat on Earth. Seawater is characterised by its high salinity which can be as high as 45,000 ppm, but varies significantly depending on the ocean or sea. The average salinity of seawater is 3.5 %, but in the Baltic Sea it is just 0.2 – 2 %, and in the Dead Sea it is significantly higher at 28 %. The temperatures fluctuate just as much.
Just like brackish water, seawater is not suitable for drinking due to its high salinity, as it makes you more thirsty. However, a lot of countries that suffer from water scarcity do not have enough fresh water sources to use for drinking water, and therefore have to resort to using seawater.
How does seawater treatment work?
In many regions on Earth, seawater desalination is a good alternative to sourcing fresh water, and it is making a significant contribution to tackling water scarcity. Seawater treatment is based on membrane technologies such as electrodialysis and reverse osmosis. Reverse osmosis has proven very effective, although it often requires additional steps, such as pre-treatment via filtration and softening. Depending on the desired water quality, aftertreatment steps, such as dosing or polishing, may also be necessary.
It is essential that the materials used are resistant to a high salinity, to ensure the units have a long service life.
What units does Herco offer for seawater treatment?
Using reverse osmosis to desalinate seawater can reduce the TDS from approx. 45,000 mg/l to around 500 mg/l (drinking water quality).
Herco offers specially designed reverse osmosis units for this very purpose which are highly corrosion-resistant and durable.
Using systems that recuperate energy can help to reduce the energy required to power the reverse osmosis process. If required, Herco also offers pre-treatment and aftertreatment, as well as bespoke solutions tailored to your requirements, such as container units.
Our sales team will be happy to advise you.
All of our products can be found in our product overview.