Summary
TNO-MEP has investigated and compared two technological systems for producing drinking water from seawater. The first system is called 'Memstill'. The water is evaporated steplessly by membrane distillation. The process is heat-driven, the heat being recovered in the same membrane module. The second system - ADP - is based on spraying seawater and air. Evaporation and recondensation occur, while differences in velocity cause the salt to precipitate. The investigations showed that the energy consumption of 'Memstill' is somewhat lower, compared with Reverse Osmosis. However, the cost price per cubic meter of water is significantly lower (NLG 1.40 per m³ as against. NLG 2.20 per m³), because heat is used as the driving force instead of electricity. In addition, the outlay on 'Memstill' appears to be lower. The mechanism underlying the ADP technology did not prove to be a realistic option, either theoretically or in practice.