Distillation plant development and cost update

Recent developments in desalination technology have resulted in significant savings in cost compared with earlier plants. Both distillation and reverse osmosis processes are now viable means of water production from a seawater source in the developing countries of the MENA area as well as in the more traditional oil-producing Gulf States. Three processes are commercially available for large size plants for desalinating seawater: multi-stage flash distillation (MSF), multiple effect distillation (MED) and reverse osmosis (RO). This paper describes the current development of the MSF and MED distillation processes and compares the costs of water production with seawater RO. Advances in plant technology and in energy efficiency have resulted in savings of up to 50% compared with costs only a few years ago. Water costs in the range of 0.7 to 0.9 US $/m(3) are now achievable, either with RO or large distillation plants, depending on the seawater source and cost of available energy. Future developments should reduce costs even further.