A novel hybrid process of reverse electrodialysis and reverse osmosis for low energy seawater desalination and brine management
This paper introduces a novel concept for a hybrid desalination system that combines reverse electrodialysis (RED) and reverse osmosis (RO) processes. In this hybrid process the RED unit harvests the energy in the form of electricity from the salinity gradient between a highly concentrated solutio...
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Main Authors: | , , , , , |
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Other Authors: | |
Format: | Article |
Language: | English |
Published: |
2013
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Subjects: | |
Online Access: | https://hdl.handle.net/10356/99732 http://hdl.handle.net/10220/11011 |
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Institution: | Nanyang Technological University |
Language: | English |
Summary: | This paper introduces a novel concept for a hybrid desalination system that combines reverse electrodialysis
(RED) and reverse osmosis (RO) processes. In this hybrid process the RED unit harvests the energy
in the form of electricity from the salinity gradient between a highly concentrated solution (e.g., seawater
or concentrated brine) and a low salinity solution (e.g., biologically treated secondary effluent or
impaired water). The RED-treated high salinity solution has a lower salt concentration and serves as
the feed solution for the RO unit to reduce the pump work. The concentrated RO brine provides the
RED unit a better high salinity source for the energy recovery compared to seawater. In addition, the concentration
of the discharged brine can be controlled by the RED unit for improving the water recovery and
minimizing the impact on the environment. Different configurations of the hybrid RED–RO processes are
presented for a comparative study on the basis of mathematical modeling. Specifically, various operating
conditions for the RED unit are investigated for better adaptation to the hybrid system. The variations of
the total specific energy consumption and the discharge brine concentration for various hybrid modes are
simulated to verify the conceptual designs. The modeling results indicate that the RED–RO hybrid processes
could substantially reduce the specific energy consumption and provide a better control of the discharge
brine concentration in comparison to conventional seawater desalination RO processes. |
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