Large increases in water demand with very little recharge have strained Libya's groundwater resources resulting in serious declines in water levels and quality, especially along the Mediterranean coast where most of the domestic, industrial and agricultural activities are concentrated. To meet these increases, Libya turned to desalination as a supplemental water resource as early as 1964. Both thermal and membrane desalination technologies have been used. MSF, MED and VS as well as ED, EDR and RO processes have been employed to provide water for domestic and industrial purposes. Applications included both brackish and seawater desalination with plant sizes ranging from less than 100 m(3)/d to 40,000 m(3)/d with a total cumulative installed capacity exceeding 0.6 MCM/d. The objective of this paper is to summarize the experience gained from operating these plants over a long period of time. To achieve this objective, design and operational data from some of these plants were analyzed with special reference to evolution of process applications, and major problems and limitations and their impacts on process performance. Based on the results of this analysis, Libya continues to be a major user of desalination technologies ranking as the world's 4th to 5th user. Thermal desalination processes (TDPs), which gained momentum in the early seventies, are the major producer accounting for about 75% of the total cumulative installed capacity. RO processes, although a relatively newcomer, come next. EDR processes account for the largest number of plants installed. Applications of all three technologies have been increasing steadily since 1972 with minor decline in the early nineties. Problems have been reported in all phases of plant development: planning, installation and start-up, operation and maintenance. These problems are administrative, technical and financial. They are presented and analyzed with due consideration to "local factors" which are usually ignored by designers/contractors. Although some of these problems are minor, if not addressed properly, their impacts on plant performance can be significant. The experience gained is invaluable on a national as well as regional level and to suppliers, end-users and professionals in the field.
