Seawater reverse osmosis

Seawater pretreatment, 16 25 Seawater reverse osmosis systems,... 

Seawater reverse osmosis, 26 97 Seawater reverse osmosis desalination systems, 26 80... 

Fig. 2.1 Increase in concentration factor and decrease in concentrate volume with increasing recovery rate. The shaded regions represent typical recovery ranges for typical seawater reverse osmosis (SWRO) and brackish water reverse osmosis (BWRO) processes...

Co-location of a power plant and a seawater reverse osmosis desalination plant allows for the cooling water from a neighbouring power plant to be blended with the waste from a desalination plant before discharge (Voutchkov 2004). In such a process, seawater is used as the cooling water for the condensers in a power plant. This water is then used as both the feed for the desahnation process, and for blending to dilute the concentrate from the desalination plant. 

Seawater reverse osmosis, especially when feed gravity pressure can be utilized. 

Figure 16. Decrease of separation (or increase of solute permeabilities) of seawater reverse osmosis desalination at several concentration levels of NaOCl. Initial membrane constants pure water permeability constant = 97.0 nmol m Pa s and the solute permeability constant for NaCl = 0.9 X 10 cm s . Operational conditions k = 7.(97 X 10 cm s Ap = 6.0 MPa, and T = 25°C.

Figure 2. Exposure of FT-30 membranes to 100 ppm chlorine in water at different pH levels. Effect on salt refection in simulated. seawater reverse osmosis tests (0) pH 1 Cn pH 5 (O) pH 8 (A) pH 12.

R.E. Larson, J.E. Cadotte and R.J. Petersen, The FT-30 Seawater Reverse Osmosis Membrane-element Test Results, Desalination 38, 473 (1981). 

Figure 5.22 Flow scheme showing the pretreatment steps in a typical seawater reverse osmosis system [50]...

The approximate operating costs for brackish and seawater reverse osmosis plants are given in Table 5.3. These numbers are old, but improvements in membrane technology have kept pace with inflation so the costs remain reasonably current. 

Table 5.3 Operating costs for large brackish water and seawater reverse osmosis plants [49]. Capital costs are approximately US 1.25 per gal/day capacity for the brackish water plant and US 4-5 per gal/day capacity for the seawater plant...

Kumar, M., S. S. Adham, and W. R. Pearce. 2006. Investigation of seawater reverse osmosis fouling and its relationship to pretreatment type. Environ, Sci. Technol. 40 2037-2044. 

Furukawa, D.H.(Sept. 1997) A review of seawater reverse osmosis. IDA Desalination Seminar, Cairo, Egypt. 

An UF system utilizing hollow-fiber (FIF) membranes has been successfully used as pretreatment prior to seawater reverse osmosis (SWRO) desalination without any chemical treatments [8]. The quality of UF permeate was good and satisfied the need of SWRO feed water [8]. 

Some of the largest plants for seawater desalination, wastewater treatment and gas separation are already based on membrane engineering. For example, the Ashkelon Desalination Plant for seawater reverse osmosis (SWRO), in Israel, has been fully operational since December 2005 and produces more than 100 million m3 of desalinated water per year. One of the largest submerged membrane bioreactor unit in the world was recently built in Porto Marghera (Italy) to treat tertiary water. The growth in membrane installations for water treatment in the past decade has resulted in a decreased cost of desalination facilities, with the consequence that the cost of the reclaimed water for membrane plants has also been reduced. 

Bou-Hamad, S., et al. (1997). Performance evaluation of three different pretreatment systems for seawater reverse osmosis technique. Desalination Int. Symp. Pretreatment of Feedwater for Reverse Osmosis Desalination Plants, March 31-April 2, 110, 1-2, 85-92. Elsevier Science B.V., Amsterdam, Netherlands. 

Sablani S.S., Goosen M.F.A., Al-Belushi R., and Gerardos V., Influence of spacer thickness on permeate flux in spiral-wound seawater reverse osmosis systems. Desalination 146 2002 225-230. 

Wilf M. and Klinko K., Effective new pretreatment for seawater reverse osmosis systems. Desalination 117 1998 323-331. 

Goosen M.F.A., Sablani S., Dal Cin M., Wilf M., Jackson D., Al-Belushki R., and AlMaskri S., Effect of high temperature and pressure on permeation properties of composite polyamide seawater reverse osmosis and brackish water nanofiltration membranes. Journal of Membrane Science (Submitted 2008). 

FIGURE 43.2 The three alignments suggested for the realization of a seawater reverse osmosis (SWRO) desalination plant between Israel and the Hashemite Kingdom of Jordan. (From http //www.mfa.gov.il/mfa.)... 

S. Ebrahim and H. El-Dessouky, Evaluation of commercial cleaning agents for seawater reverse osmosis membranes. Desalination 99, 169-188 (1994). 

Generally, the salt rejections observed for these membranes in seawater reverse osmosis tests did not exceed 80 percent. This process was applied at Albany International to form composite membranes on hollow polysulfone fibers (25). Salt rejections on the hollow fiber membranes were above 98 percent at an average flux of about 1.5 gfd (2.5 L/sq m/hr) in a 12 000-hour test using 30 000 ppm seawater at 1000 psi. In other 5000-hour tests using 3500 ppm brackish water at 400 psi with addition of 100 ppm chlorine at pH 8 flux and salt rejection remained constant at 1 gfd and 98 percent respectively (Figures 8 and 12 in Reference 25 a). 

Properties of FT-30. The properties of FT-30 membranes have been reviewed in several publications. Therefore, only the salient features that relate to the chemistry of the barrier layer will be considered here. Reverse osmosis performance of FT-30 under seawater and brackish water test conditions was described by Cadotte et al (48) and by Larson et al (51). In commercially produced spiral-wound elements the FT-30 membrane typically gives 99.0 to 99.2 percent salt rejection at 24 gfd (40 L/sq m/hr) flux in seawater reverse osmosis tests with 3.5 percent synthetic seawater at 800 psi (5516 kPascaJJand 25°C. 

Both the brackish and seawater reverse osmosis product water costs are based on 1982 costs and they are indicative of specific plants in an assumed location in the southern United States. The cost of energy in the seawater system assumes that the reject from the first stage high pressure reverse osmosis system is sent to an energy recovery system which reduces the overall energy requirements for the total system by 31%. 

DC Hicks, C M Pleass, W A Fearn and D Staples, Development, testing and the economics of a composite/plastic seawater reverse osmosis pump . Desalination... 

V. Murugan, K. Rajanbabu, S.A. Tiwari, C. Balasubramanian, M.K. Yadav, A.Y. Dangore, S. Prabhakar, P.K.Tewari, Fouling and cleaning of seawater reverse osmosis membranes in Kalpakkam nuclear desalination plant, Int. J. Nucl. Desal. 2,2006,172-178. 

J.E. Cadotte, R.J. Petersen, R.E. Larson, E. E. Erickson, A new thin-film composite seawater reverse osmosis membrane. Desalination 32 (1980) 25. 

B. Penate, L. Garcia-Rodriguez, Current trends and future prospects in the design of seawater reverse osmosis desahnation technology. Desalination 284 (2012) 1—8. 

T.M. Missimer, R.G. Mahva, M. Thompson, W.S. Manahan, K.P. Goodboy, Reduction of seawater reverse osmosis treatment costs by improvement of raw water quahty innovative intake designs, Desal. Water Reuse 20 (3) (2010) 12-22. 

T. Waly, M.D. Kennedy, G.-J. Witkamp, G. Amy, J.C. Schippers, The role of inorganic ions in the calcium carbonate scaling of seawater reverse osmosis systems, Desalination 284 (2012) 279-287. 

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