forward osmosis: desalination processes forward osmosis: desalination modern water owns, installs...
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Membrane Processes
Forward Osmosis: DesalinationModern Water owns, installs and operates world-leading membrane technologies and we are the world-leader in Forward Osmosis (FO) technology. We have successfully implemented and operated our patented desalination process internationally and produce fresh water in some of the most demanding seawater conditions in the world.
Our FO process consistently delivers significant reductions in operational costs, reduced lifetime costs and it reliably produces high quality product water, even in the most challenging conditions.
We use our world-leading FO technology platform in a number of membrane process applications other than for seawater or brackish water desalination. These include: evaporative cooling systems, secondary oil recovery and the development of renewable energy using hydro osmotic power (HOP).
FO desalination benefits
A proven, reliable and robust membrane process
Energy consumption typically up to 30% lower than conventional Reverse Osmosis (RO)
Inherently low fouling characteristics (both particulate and biological fouling)
Significantly reduced product boron levels without post-treatment when compared to conventional RO
Higher availability than a conventional RO plant due to low fouling, simple cleaning and ease of operation
Technology Status Membrane Fouling Energy Consumption Operational Costs Boron Removal Ease of Operation Capital Cost
Forward Osmosis (FO)
Innovative process solution now fully operational & commercially available (Al Khaluf, Oman - the world’s first commercial FO plant began operation in 2010).Competitive advantages over RO.Significant further process improvements to come.
Extremely low inherent fouling - low pressure, diffusion driven process.Possibility to consider reduced pre-treatment. * site dependentFO Membranes are chlorine tolerant allowing effective treatment for bio-fouling.
Typically up to 30% less than RO.The more difficult the feedwater the higher the energy saving.
Less than RO due to higher availability, less chemical cleaning and fewer membrane replacements.Extended membrane life - FO membrane life typically twice that of the equivalent RO membrane.
Inherently high removal, without the need for post treatment (less than 1 ppm).
Very similar to RO, but with less frequent cleaning and increased membrane life.
Similar capital cost on a like-for-like basis.
Reverse Osmosis (RO)
Mature, well established technology (Coalinga, California - the world’s first commercial RO plant began operation in1965).Little further improvement likely.
High pressure - prone to fouling, hydraulic forces increase fouling - a key issue.RO Membranes are not chlorine tolerant.
Typically up to 30% more than FO.Any degree of fouling, higher than FO.
More than FO due to lower availability, higher energy costs, more chemical cleaning and membrane replacements.
Poor removal and may require additional costly post treatment system.
Similar to FO but more frequent cleaning and reduced membrane life.
Similar capital cost on a like-for-like basis
Forward Osmosis Vs Reverse Osmosis
1 3
Product 72 m3/d
Brine 216 m3/d
Source Water
(Seawater or brackish
water)
OsmoticAgent(High
Osmotic Pressure)
Forward Osmosis (FO) Reverse Osmosis (RO)
RO
A1 Khaluf RO Plant
P1
P2
P1 - P2 > ∆ ∏
∆ ∏
∆ ∏
25% Conversion 65 barg
25kW
FO
A1 Khaluf FO Plant
35% Conversion 4 barg
2kW
Product in OA 100 m3/d Product 100 m3/d
Brine 188 m3/d Regeneration
42% reduction inenergy consumptionvs RO at A1 Khaluf
47% Conversion 65 barg
19kW
Feed 288 m3/d
Feed 288 m3/d
1
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Jan 2010 Feb 2010 Mar 2010 Apr 2010 May 2010 Jun 2010 Jul 2010 Aug 2010 Sep 2010 Oct 2010 Nov 2010 Dec 2010
FO N
orm
alise
d Fl
ow (
m 3 /
h)
AI Khaluf FO Plant
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Jan 2010 Feb 2010 Mar 2010 Apr 2010 May 2010 Jun 2010 Jul 2010 Aug 2010 Sep 2010 Oct 2010 Nov 2010 Dec 2010
Nor
mal
ised
Perm
eate
Flo
w (
m 3 /
h)
AI Khaluf RO Plant
Membranes Installed
August 2009, 4.2 m 3/hNew Membranes Installed
Cleaning Activity on New Membranes
30% Decline in Output Over Just Five Months
Typical Year
Typical Year
4
2
3
2
A1 Khaluf, Oman
Process explained
At the heart of the Modern Water process is a recirculating “osmotic agent” system that transfers pure water from the feedwater (eg seawater) to the regeneration (permeate extraction) system.
By linking two highly optimised systems, the FO system and the regeneration system, significant benefits are achieved.
In the first stage, feedwater is fed under low pressure to the forward osmosis membranes, which are highly resistant to fouling and are resistant to oxidising agents. The osmotic agent, on the other side of the membrane, draws fresh water from the seawater due to a difference in osmotic pressure. This fresh water dilutes the osmotic agent.
In the second stage, permeate is extracted from the system. The pure water is removed from the dilute osmotic agent which is regenerated (or concentrated) for reuse in the first stage. This can be achieved in a number of ways depending on the proprietary osmotic agent selected.
Technology Status Membrane Fouling Energy Consumption Operational Costs Boron Removal Ease of Operation Capital Cost
Forward Osmosis (FO)
Innovative process solution now fully operational & commercially available (Al Khaluf, Oman - the world’s first commercial FO plant began operation in 2010).Competitive advantages over RO.Significant further process improvements to come.
Extremely low inherent fouling - low pressure, diffusion driven process.Possibility to consider reduced pre-treatment. * site dependentFO Membranes are chlorine tolerant allowing effective treatment for bio-fouling.
Typically up to 30% less than RO.The more difficult the feedwater the higher the energy saving.
Less than RO due to higher availability, less chemical cleaning and fewer membrane replacements.Extended membrane life - FO membrane life typically twice that of the equivalent RO membrane.
Inherently high removal, without the need for post treatment (less than 1 ppm).
Very similar to RO, but with less frequent cleaning and increased membrane life.
Similar capital cost on a like-for-like basis.
Reverse Osmosis (RO)
Mature, well established technology (Coalinga, California - the world’s first commercial RO plant began operation in1965).Little further improvement likely.
High pressure - prone to fouling, hydraulic forces increase fouling - a key issue.RO Membranes are not chlorine tolerant.
Typically up to 30% more than FO.Any degree of fouling, higher than FO.
More than FO due to lower availability, higher energy costs, more chemical cleaning and membrane replacements.
Poor removal and may require additional costly post treatment system.
Similar to FO but more frequent cleaning and reduced membrane life.
Similar capital cost on a like-for-like basis
Product 72 m3/d
Brine 216 m3/d
Source Water
(Seawater or brackish
water)
OsmoticAgent(High
Osmotic Pressure)
Forward Osmosis (FO) Reverse Osmosis (RO)
RO
A1 Khaluf RO Plant
P1
P2
P1 - P2 > ∆ ∏
∆ ∏
∆ ∏
25% Conversion 65 barg
25kW
FO
A1 Khaluf FO Plant
35% Conversion 4 barg
2kW
Product in OA 100 m3/d Product 100 m3/d
Brine 188 m3/d Regeneration
42% reduction inenergy consumptionvs RO at A1 Khaluf
47% Conversion 65 barg
19kW
Feed 288 m3/d
Feed 288 m3/d
4
Seawater or brackishwater feed Reject from FO System
DilutedOsmotic Agent
ConcentratedOsmotic Agent
Product WaterRegeneration System
FO System
5
5
=
DesalJan13
To find out how we can help you please contact us on:
+ 44 (0)1483 696 000
www.modernwater.com
Modern WaterVilla 10593Way No 4494 AzaibahMuscatSultanate of Oman
+ 968 244 918 33
Modern WaterUnit 1701-2 Westgate Tower 1038 Nanjing Road WShanghai 200041China
+ 86 21 6218 5183 Ext.140
Modern Water plcBramley House, The GuildwayOld Portsmouth RoadGuildfordSurrey GU3 1LR United Kingdom
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