Seawater contains significantly higher concentrations of dissolved salts than groundwater or brackish water. Typical seawater contains approximately 35 grams of dissolved salts per litre (35 g/L), with sodium chloride (NaCl) representing the largest fraction. Common dissolved ions include sodium (Na⁺), chloride (Cl⁻), magnesium (Mg²⁺), sulfate (SO₄²⁻), calcium (Ca²⁺), potassium (K⁺), and smaller amounts of bromide (Br⁻) and other trace elements. To produce drinking water or process water from seawater, desalination processes are normally required, with reverse osmosis (RO) being the most widely used technology.
Common Challenges
- High Salinity
- Corrosion
- Organic Matter and Algae
- Biofouling and Scaling
- Higher Energy Demand than Brackish Water
Common Treatment Methods
- Screen Filtration
- Sand Filtration
- Fine Filtration
- Seawater Reverse Osmosis (SWRO)
- UV Disinfection
Advantages
- Virtually Unlimited Water Resource
- Can Produce High Quality Drinking Water
- Globally Established Technology
Limitations
- Higher energy consumption than most other water treatment technologies
- Requires extensive pretreatment to protect membranes from particulates, organic matter and fouling
- Produces a concentrated brine stream containing salts, minerals and other constituents removed from the feed water which must be managed appropriately
Example Treatment Trains
Seawater
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Screen Filter
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Sand Filter
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Fine Filtration
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SWRO
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UV Disinfection
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Drinking Water
Seawater
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Screen Filtration
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Sand Filtration
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Fine Filtration
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ModuPure™ RO
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UV Disinfection
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Drinking Water
Although seawater represents a vast water resource, desalination generally requires more energy than treatment of groundwater or lake water. Proper water analysis and system design are therefore important when selecting a technically and economically suitable solution.