Feedwater types that work with solar desalination
Solar desalination can treat a variety of saline and contaminated water sources, but suitability depends on the system type and the water's chemical and biological characteristics. Typical feedwater sources include:
- Seawater: the most common source for coastal and island systems; requires robust desalination and brine handling.
- Brackish groundwater: lower salinity than seawater and often cheaper to treat with membrane systems.
- Saline lakes and estuarine waters: can be treated if pre-treatment addresses turbidity and organic content.
- Contaminated surface water or wastewater: treated with combined pre-treatment and disinfection steps before desalination or as part of reuse systems.
Factors that influence choice:
- Salinity level: higher salinity increases energy and equipment demands.
- Turbidity and suspended solids: high turbidity requires pre-filtration to prevent fouling in membranes or scaling in thermal units.
- Organic matter and biological load: can cause biofouling; pre-treatment with coagulation, filtration, or UV may be needed.
- Chemical contaminants: heavy metals or industrial pollutants may require specialized treatment steps.
A practical approach is to sample and analyze potential feedwater and match the system to its quality. For example, PV-powered RO is efficient for low-to-moderate salinity water with manageable turbidity, while thermal methods handle very high salinity but need more space or heat input. Combining pre-treatment steps improves reliability and prolongs system life.