desalination future trends and challenges
TRANSCRIPT
D E S A L I N A T I O N
• The process of removing salt from seawater
• Typical example is water and brine system
M E T H O D S U S E D F O R D E S A L I N A T I N G
W A T E R
• Sea Water Reverse Osmosis (SWRO)
• Forward Osmosis (FO)
In seawater RO systems, pressure is
applied to seawater forcing water through
a semi-permeable membrane while most
salts, colloids, bacteria and other
impurities are rejected by membrane
R O
T E C H N I C A L
A D V A N T A G E S
• Versatile - treats all types of water
brackish-seawater
• Adaptable to all sizes of installation and
energy sources eg electricity, steam
• Setting up in all geographic zones
possible
• Minimal environmental impact
• Flexibility - plant sizes;can increase
production and hence plant size to
accommodate requirement
• Operation costs proportional to flow
variations
Things to Think About
Membranes sensitive to
abuse & feed water
needs pre-treatment to
remove particulates
Operation - high quality
materials
Safe & careful disposal
of brine
Risk of
membranes to
bacterial
contamination
T Y P I C A L F E A T U R E S O N A N R O
P L A N T
• Standard features of RO systems inc. major components such
as cartridge filter, pressure vessels, membrane elements, high
pressure pumps and control instrumentation w/failsafe devices
• Energy Recovery Devices comprises pressure exchanger and
booster pump
• Cleaning In Place (CIP Unit) comprises cleaning pump,
cleaning tank, bag filter, instrument control panel
• Post-Treatment System comprises chemical dosing units
(neutralisation or chlorination)
- Membrane biofouling
- Protecting SWRO from red blossom
algae
- Need to drive down energy costs
- Treating brine reject for beneficial use
eg as salts/road salts, providing
feedstock to chemical industry
- The need for driving down capital
costs for thermal desalination units
- Environmental impact concerns for
large scale desalination
C H A N G E S O N T H E H O R I Z O N
• Use of Forward Osmosis technology - developments in
stand alone systems or combination technologies use
with RO => lower energy consumption
• Using waste heat in desalination => lower energy
costs
S U M M A R Y
• Reverse Osmosis been established
a mature and sustainable
technology for seawater treatment
• New technologies platforms such
as Forward Osmosis (FO) aim to
improve RO, and are applicable
with multiple benefits
• These process focus on reducing
energy consumption and prevent
scaling/biofouling commonly
associated with membrane
technology