Seawater Desalination by using Nanofiltration (NF) and Brackish Water Reverse Osmosis (BWRO) Membranes in Sequential Mode of Operation

Document Type: Research Paper

Authors

1 Ege University

2 Chem Eng Dept, Ege University

3 Atılım University

Abstract

In this study, the applicability of nanofiltration (NF) membranes as a pretreatment prior to reverse osmosis (RO) in seawater desalination was investigated. The membranes used were
NF270 and NF90 as the NF membranes, while the brackish water (BW) RO membrane BW30 was used as the RO membrane. In desalination tests, permeates of the NF membranes
were collected and used as the feed to the BW30 membrane. The calculated permeate fluxes were 6.7 L/h.m2, 11.3 L/h.m2, 24.3 L/h.m2, and 36.6 L/h.m2 for single BW30-35 bar,
NF270-30 bar + BW30-35 bar, NF90-30 bar + BW30-25 bar and NF90-30 BW30-35 bar, respectively. The calculated water recovery and rejected salt values were 51.6%, 41.4%,
24.8%, 15.4% and 98.2%, 98.2%, 96.0%, 91.0% for NF90-30 bar + BW30-35 bar, NF90-30 bar + BW30-25 bar, NF270-30 bar + BW30-35 bar and single BW30-35 bar, respectively.
The qualities of the product waters of integrated systems (NF+BWRO) and the single BWRO system were also investigated. Boron rejection was fairly well with average boron
rejections of 59.3% and 60.2% by NF90-30 bar + BW30-25 bar and NF90-30 bar + BW30-35 bar combinations, respectively while single BW30-35 bar gave an average rejection of
49.6%. The results obtained showed that the quality of product water obtained using single BWRO did not comply with the irrigation standards, while the integrated systems provided
total compliance to irrigation standards with the exception of boron.

Graphical Abstract

Seawater Desalination by using Nanofiltration (NF) and Brackish Water Reverse Osmosis (BWRO) Membranes in Sequential Mode of Operation

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