Reverse Osmosis Desalination
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For seawater
For brackish water
The global leader in water treatment,
Veolia Water Solutions &Technologies
The global leader in water treatment,
Veolia Water Solutions &Technologies
(VWS) has over 100 years of proven experience in thermal and membrane
desalination and the leading capacity
in the market with a production of
5.2 millions of m3/day.
With first class reverse osmosis references
ranging from modular installations
to large turnkey plants with capacities
of up to 350,000 m3/day, VWS provides
its customers with a full range of
solutions tailored to their specific
desalination requirements.
VWS expertise in reverse osmosis desalination
For local authorities, supplying fresh water to
everyone has become a key environmental
and economic issue. Desalination represents
an effective solution to meet the
challenges of rapid population and
economic growth, to face water
natural shortages and to prevent
overextraction and pollution
of coastal fresh groundwater.
Adaptable to all capacities,
Reverse Osmosis is the most
widespread desalination process
and well-suited when local energy
source is not available. Through
technology improvement, costs of
RO desalination have dramatically
decreased, making this technology
highly competitive.
Based on extensive experience in
operating membrane technologies since
the 1960’s, VWS provides global project
management coupled with a sustainable
approach to customized desalination
projects from design to construction
and
maintenance.
Understanding
customers’ environmental and economic
constraints, providing answers to water
scarcity and pollution issues, considering
the inlet water quality and integrating the
membrane technology in the entire
treatment line are all taken into account
within VWS’ sphere of expertise. Through
its specialized subsidiaries and local
entities, VWS offers customized and
packaged solutions to ensure plant
performance and high water quality.
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Global management of RO desalination line
Adapting water intake designs to
local environment
Taking into account natural features (rock nature,
seashore profile, water quality), VWS adapts the
intake design to your specificity. Pumped directly
from sea or from wells, the quality of raw water will
strongly condition subsequent treatments and
equipments.
Providing customized pre-treatment solutions
Because reverse osmosis is very sensitive to water quality, an efficient pre-treatment system is required.
With its unequaled experience in water treatment and its pilot testing program, VWS designs the best suited
pre-treatment line for its customers to reach the final water quality objectives.
Selecting RO membrane technologies
Through ARAMIS®, the membrane expertise center of Veolia
Water, VWS is able to ensure the best choice of RO
membranes for each application. ARAMIS® provides appropriate
technical support to optimize membrane operating conditions
by characterizing all membranes available on the market
(performance testing, diagnostic aging properties) and by
performing membrane autopsies (deposits identification
and suggestions of pre-treatment solutions).
Supervising post-treatments to fulfill high standards
Treating water after the reverse osmosis process is necessary to reach the final quality objectives, depending
on its diverse needs and applications. For drinking water standards, the water will undergo remineralization,
neutralization (adjustment of hardness, alkalinity and pH) and finally, disinfection.
Reducing environmental impacts of concentrates
Desalination processes result in production of brines. VWS commits to sustainable development thorough
assessments of the environmental impact in order to ensure the most efficient solution for concentrates
discharge. Looking ahead, VWS develops advanced solutions such as Zero Liquid Discharge (ZLD) systems
using our HPD evaporation and crystallisation technologies.
Optimizing energy recovery
Reverse osmosis process operates under pressure and the energy
requirement represents one third of the global desalination cost. VWS
couples its desalination facilities with Energy Recovery Devices (ERD),
which allow reduced operating expenses and improved desalination
process efficiency. The pressure exchanger systems recover 90% of
the energy, reducing energy demand by between 10-50% and therefore
reducing operating costs.
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An unlimited range of pre-treatment solutions
acid coagulant
acid coagulant
Media filtration
Media filtr
stage
polymer
FLOCCULATION
acid coagulant
U
M
SEAWATER
BRACKISH WATER
acid coagulant
polymer
coagulant
FLOTATION
acid coagulant
polymer
SETTLING
ACTIFLO®
Ballasted settling
coagulant
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Dual media filters
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Customized reverse
osmosis pre-treatment
solutions
Pre-treatment is a key issue in designing
desalination plants to optimize RO
membranes performance and extend
membrane life span.
filtration
age 2
acid
Prefilter
RO MEMBRANES
ULTRAFILTRATION
MICROFILTRATION
HP pump
antiscalant
Booster
pump
Ultrafiltration skids
Raw seawaters show large variability in
salinity, temperature, turbidity, organic
matters, biological and mineral contents,
all depending on geography, season
(e.g. algae bloom) and local pollution
(e.g. hydrocarbons). Brackish water
quality also varies, though to a lesser
extent. To prevent RO membrane fouling
and clogging, the pre-treatment line
should be adapted to raw water
characteristics in order to successfully
reduce:
• Turbidity and associated suspended
solids (SS). Turbidity should be lower
than 0.2 NFU.
• Silt Density Index. The target SDI average
value being 3. SDI measures the water
fouling potential on a membrane.
Reducing SDI means removing algae,
plankton, micro-organisms, organic
compounds and holding down mineral
precipitation.
VWS offers a wide range of pre-treatment
technologies:
• Conventional clarification lines (i.e.
with coagulation, flocculation and
mono or dual media filtration stages).
• Advanced clarification processes such
as ACTIFLO® and flotation, adapted to
water with high organic compounds.
• Advanced membrane technologies
for fine filtration (ultrafiltration,
microfiltration).
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Packaged Solutions
VWS offers skid-mounted pre-engineered desalination units that can be used for all types of applications
(drinking, irrigation, industrial process). These compact and flexible units optimize transportation and
installation. RO skids provide reliable solutions for isolated areas as well as for temporary needs (tourism,
pollution, natural shortage) or space limited environments (offshore platforms, on-board-ships).
• Wide range of capacities, up to 20,000 m3/day
• Short delivery time, up to 40% shorter than for a field-erected plant
• Easy and quick installation
• Minimum installation-related risks by shop assembling
• Cost reduction thanks to standardization
• Complete plant control system with optional SCADA system
• Low maintenance
Reverse osmosis
fundamentals
Osmosis membranes act as a
filter retaining all dissolved
species bigger than 1 Angström
(e.g. bacteria, viruses, organic
matters) as well as monovalent
and bivalent ions.
When membranes separate two
water types, water molecules
pass from the less concentrated
zone into the more concentrated
zone in order to balance ionic
forces.
Desalator units
To reverse the natural flow of
water through the membrane,
pressure greater than osmotic
pressure has to be applied on the
concentrated solution (i.e. more
than 32 bars for seawater of 40 g/l).
Associated services
Providing pressures from 70 to
84 bars, 40 to 60% of seawater or
brackish water is converted into
fresh water by reverse osmosis.
To ensure long-term success of a project and anticipate future needs,
VWS offers its customers a wide range of services:
• Hydrogeological modeling
• Pilot Plants, to test process suitability on-site
• Software systems for management
• Maintenance Services and Technical Assistance
The influent saline solution
is divided into two phases:
the permeate (fresh water free
of particulates and dissolved
impurities) and the concentrate
stream (brine enriched with
suspended and dissolved solids).
Veolia Water Solutions & Technologies
“L’ Aquarène”
1 place Montgolfier
94417 Saint-Maurice Cedex - France
Tél. : +33 (0)1 45 11 55 55
Fax : +33 (0)1 45 11 55 00
Yv’Anik Conseils 01 40 45 79 75 - 06/07 - Photos : VWS - Photothèque VE
Your contact:
www.veoliawaterst.com
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Reverse Osmosis Desalination