Encyclopedia of Environmental Science and Engineering, Volume I and II

DESALINATION 221

Large capacity plants usually produce, to some extent,

cheaper water than small capacity plants.

Energy is usually an expensive item. The proposal to use

cheap waste heat from nuclear plants failed, due to many rea-

sons connected to the coupling of the two systems. Today the

problem is reexamined and the trends are in favor of nuclear

desalination. Nevertheless, no large plants have been erected.

The two leading processes of desalination are the MSF

distillation and the reverse osmosis. In Table 3 the costs of

the two processes are compared.

TABLE 3

MSF versus RO seawater desalting costs

Plant capacity m^3 /d (mgd)

3.8(1) 11.4(3) 18.9(5.0) 37.9(10.0)

Total capital cost $ × 103

MSF 8.621 19.737 30.928 54.337

RO 5.887 15.581 24.082 43.01

Total operating $ × 103

MSF 2.064 4.94 7.785 14.401

RO 1.758 4.675 7.404 13.806

Cost of product water

MSF $/m^3 ($/kgallons) 1.65 (6.29) 1.32 (5.01) 1.25 (4.74) 1.15 (4.38)

RO $/m^3 ($/kgallons) 1.41 (5.35) 1.25 (4.74) 1.19 (4.51) 1.11 (4.20)

0

2

4

6

8

10

12

14

16

18

20

1965 1970 1975 1980 1985 1990

YEAR OF OPERATION

CAPACITY INSTALLED, 10

6 m’/d

TOTAL DESALINATION

TOTAL DISTILLATION

MSF DISTILLATION

REVERSE OSMOSIS

ELECTRODIALYSIS

1960 1995

FIGURE 21

C004_001_r03.indd 221C004_001_r03.indd 221 11/18/2005 10:19:02 AM11/18/2005 10:19:02 AM