several modified forms of these modules (Eckman 1995;
Solomon 1989; Casey 1983, 1984). Early BWRO plants
employed low fouling plate and frame and tubular module
designs. Both of these modules, however, were gradually
abandoned and substituted with more economical, compact
and high throughput spiral wound and hollow fiber modules
(Kucera 2014; Dupont et al. 1982). A short comparison and
selection criteria for main types of BWRO module designs
are overviewed in Table 4. Critically important parameters
include manufacturing cost, packing density, membrane
material specificity, membrane fouling, concentration
polarization, ease of cleaning, mechanical sustainability
against high pressure, and magnitude of permeate-side
pressure drop (Baker 2012; Kucera 2010).
4.1 Plate and Frame Modules
The initial desalination membrane systems were constructed
on the basis of plate and frame module designs (Günther
et al. 1996). In such designs, numerous grooved flat sheet
membrane envelopes along with feed and product spacers
arranged in series are stacked together between two rigid
endplates made of glass fiber, reinforced paper, or plastic
Table 2 Desalination properties
of integrally skinned asymmetric
membranes for brackish water
purification
Base polymer
Permeate flux
(m
3
/m
2 day)
Salt
rejection
(%)
Test
conditions
References
Polyamide
0.05
99
5000 ppm
NaCl,
27.6 bar
Mehta and Loeb
(1978)
Polybenzimidazole
0.13
95
1050 ppm
NaCl,
5.89 bar
Senoo et al. (1971)
Polybenzimidazoline
0.61–0.65
90.0–
95.0
5000 ppm
NaCl,
18.3 bar
Goldsmith et al.
(1977)
Polyimide
0.49
97
5000 ppm
NaCl,
28.6 bar
Fox (1980)
Polyoxadiazole
1.50 Â 10
−7
92
5000 ppm
NaCl,
44.1 bar
Sekiguchi et al.
(1978)
Polypiperazinamide
0.67
97.2
3600 ppm
NaCl,
80.0 bar
Lee et al. (2011),
Credali et al. (1975)
Blend of cellulose acetate
and polyvinylpyrrolidone
0.60–1.56
–
Pure water,
0.35 bar
Saljoughi and
Mohammadi (2009)
Fig. 3 Schematic diagram of
thin-film interfacial composite
membrane
Recent Trends in Membrane Processes for Water Purification …
45
Solomon 1989; Casey 1983, 1984). Early BWRO plants
employed low fouling plate and frame and tubular module
designs. Both of these modules, however, were gradually
abandoned and substituted with more economical, compact
and high throughput spiral wound and hollow fiber modules
(Kucera 2014; Dupont et al. 1982). A short comparison and
selection criteria for main types of BWRO module designs
are overviewed in Table 4. Critically important parameters
include manufacturing cost, packing density, membrane
material specificity, membrane fouling, concentration
polarization, ease of cleaning, mechanical sustainability
against high pressure, and magnitude of permeate-side
pressure drop (Baker 2012; Kucera 2010).
4.1 Plate and Frame Modules
The initial desalination membrane systems were constructed
on the basis of plate and frame module designs (Günther
et al. 1996). In such designs, numerous grooved flat sheet
membrane envelopes along with feed and product spacers
arranged in series are stacked together between two rigid
endplates made of glass fiber, reinforced paper, or plastic
Table 2 Desalination properties
of integrally skinned asymmetric
membranes for brackish water
purification
Base polymer
Permeate flux
(m
3
/m
2 day)
Salt
rejection
(%)
Test
conditions
References
Polyamide
0.05
99
5000 ppm
NaCl,
27.6 bar
Mehta and Loeb
(1978)
Polybenzimidazole
0.13
95
1050 ppm
NaCl,
5.89 bar
Senoo et al. (1971)
Polybenzimidazoline
0.61–0.65
90.0–
95.0
5000 ppm
NaCl,
18.3 bar
Goldsmith et al.
(1977)
Polyimide
0.49
97
5000 ppm
NaCl,
28.6 bar
Fox (1980)
Polyoxadiazole
1.50 Â 10
−7
92
5000 ppm
NaCl,
44.1 bar
Sekiguchi et al.
(1978)
Polypiperazinamide
0.67
97.2
3600 ppm
NaCl,
80.0 bar
Lee et al. (2011),
Credali et al. (1975)
Blend of cellulose acetate
and polyvinylpyrrolidone
0.60–1.56
–
Pure water,
0.35 bar
Saljoughi and
Mohammadi (2009)
Fig. 3 Schematic diagram of
thin-film interfacial composite
membrane
Recent Trends in Membrane Processes for Water Purification …
45