Reverse osmosis

Membrane distillation

Engineering

Energy recovery

Ecology

Biology

Distillation

Statistics

Brine

Chromatography

Energy (signal processing)

Biochemistry

Multiple-effect distillation

Salinity

Geothermal desalination

Waste management

Environmental engineering

Organic chemistry

Membrane

Desalination

Mathematics

Process engineering

Environmental science

Chemistry

Forward osmosis

Osmotic power

Boiler (water heating)

Boiler feedwater

New developments in pressure- and thermally driven membrane desalination technologies offer the potential to cost-effectively treat high-salinity waters, especially when powered by low-cost solar electricity and thermal energy. This paper presents a comparative techno-economic assessment of the state-of-the-art most promising pressure- and thermally driven membrane technologies for high recovery desalination, namely, osmotically-assisted reverse osmosis (OARO) and batch-operated vacuum-air-gap membrane distillation (batch V-AGMD), to produce potable water while concentrating brine within the range of 140–290 g/L TDS for minimum-liquid-discharge (MLD) and zero-liquid-discharge (ZLD) applications. It is shown that both OARO and batch V-AGMD can treat feedwater and brines with TDS in the range of 30–125 g/L with corresponding fresh water recovery rates of 85–25%. When low cost solar electricity and thermal energy are used, the resulting levelized cost of water (LCOW) from OARO is in the range of 0.70–6.28 $/m3, and that from batch-V-AGMD is in the range of 1.74–2.77 $/m3. OARO is more cost-effective than batch V-AGMD when feedwater salinity is below 70 g/L and recovery below 75%, whereas batch V-AGMD is more cost-effective at higher recovery rates and salinity levels. The sensitivity of this comparison on energy prices and module costs is discussed.

Comparative techno-economic assessment of osmotically-assisted reverse osmosis and batch-operated vacuum-air-gap membrane distillation for high-salinity water desalination