g techniques has been addressed by Conlon et al. (1) and Cress (42-46).
[Use of dual piping systems for waters of different qualities is gaining some favor as an alternative to expensive special treatment, which desalination is. Okun (52-64) has published a summary of the concept--St. Petersburg, FL had the first major system (61-62), and he has specifically compared it to membrane desalting techniques for drinking water only (63).]
In Florida. Dykes and Conlon wrote in 1989 that membrane technology has been applied "for decades"--first for sea water--in what have become "almost 100" Florida water systems (1); a summary is still available on the Internet (1-2). In 1996, Bergman (32-43) summarized Florida softening (costs) by membrane (desalination) techniques. An exhaustive 1994 review of membrane technologies for brine treatment and softening is that by Morin (42-54). In his summary table of 63 American plants, Morin (44) shows that 36 are in Florida--the dominant applier of the technology. Many Florida towns and cities, like Nokomis and Vero Beach, have two or three plants; Sarasota has five (Morin 44).
Desalination is not a 1990s technology. Texts that cover the theory--the relative energy uses, efficiencies, and costs--were primarily outdated by 1980 (Wright 26-34; Steinbruchel and Rhinesmith 111-65). Others fairly well finished the discussions before 1990 (Silver 1-30; Hahn 321-342).
Processes Generally Available. The best review of feasibility considerations of alternate desalination processes is that by Silver (5-12). He crystallizes the choice as a balance among economic cost, environmental and other social costs (less for desalination processes than for many alternative supply-treatment schemes), energy consumption, and thermodynamic efficiency (6-7). Silver (17) divides the processes into "two main classes": a) thermal processes, e. g., flash or boiling distillation, whose main energy input is heat; a...