Reverse Osmosis Desalination

• For seawater

• For brackish water

The global leader in water treatment,

Veolia Water Solutions &Technologies

VWS expertise in reverse osmosis desalination

The global leader in water treatment,

Veolia Water Solutions &Technologies

(VWS) has over 100 years of proven ex-

perience 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.

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 processand well-suited when local energysource is not available. Throughtechnology improvement, costs of

RO desalination have dramaticallydecreased, making this technology

highly competitive.

Based on extensive experience in operating membrane technologies sincethe 1960’s, VWS provides global projectmanagement coupled with a sustainable

approach to customized desalination projects from design to construction and maintenance. Understanding customers’ environmental and economicconstraints, providing answers to waterscarcity and pollution issues, consideringthe inlet water quality and integrating themembrane technology in the entire treatment line are all taken into accountwithin VWS’ sphere of expertise. Throughits specialized subsidiaries and local entities, VWS offers customized and packaged solutions to ensure plant performance and high water quality.

Global management of RO desalination line

Adapting water intake designs tolocal environmentTaking into account natural features (rock nature,seashore profile, water quality), VWS adapts theintake design to your specificity. Pumped directlyfrom sea or from wells, the quality of raw water willstrongly condition subsequent treatments andequipments.

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 suitedpre-treatment line for its customers to reach the final water quality objectives.

Selecting RO membrane technologies Through ARAMIS®, the membrane expertise center of VeoliaWater, VWS is able to ensure the best choice of RO membranes for each application. ARAMIS® provides appropriatetechnical support to optimize membrane operating conditionsby characterizing all membranes available on the market(performance testing, diagnostic aging properties) and byperforming membrane autopsies (deposits identificationand 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, dependingon 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 concentratesDesalination processes result in production of brines. VWS commits to sustainable development thoroughassessments 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) systemsusing our HPD evaporation and crystallisation technologies.

Optimizing energy recoveryReverse 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.

8914 CHEMISE 4P DESSALEMENT GB.qxd:GB-int-Dessalement 1/10/07 8:15 Page 3

An unlimited range of pre-treatment solutions

coagulant

coagulant

polymer

polymer

polymer

coagulantacid

coagulantacid

coagulantacid

coagulantacid

coagulantacid

Media filtration

Media filtrstage

SEAWATERBRACKISH WATER

FLOCCULATION

UM

FLOTATION

SETTLING

ACTIFLO®Ballasted settling

8914 CHEMISE 4P DESSALEMENT GB.qxd:GB-int-Dessalement 1/10/07 8:15 Page 4

filtrationage 2

Prefilter

ULTRAFILTRATIONMICROFILTRATION

RO MEMBRANES

acid

antiscalant

HP pump

Boosterpump

Customized reverseosmosis pre-treatmentsolutions

Pre-treatment is a key issue in designing desalination plants to optimize RO membranes performance and extendmembrane life span.

Raw seawaters show large variability insalinity, temperature, turbidity, organicmatters, 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 lesserextent. To prevent RO membrane foulingand clogging, the pre-treatment lineshould be adapted to raw water characteristics in order to successfullyreduce:

• Turbidity and associated suspendedsolids (SS). Turbidity should be lowerthan 0.2 NFU.

• Silt Density Index. The target SDI averagevalue being 3. SDI measures the waterfouling potential on a membrane.Reducing SDI means removing algae,plankton, micro-organisms, organic compounds and holding down mineralprecipitation.

VWS offers a wide range of pre-treatmenttechnologies:

• Conventional clarification lines (i.e.with coagulation, flocculation andmono or dual media filtration stages).

• Advanced clarification processes such as ACTIFLO® and flotation, adapted towater with high organic compounds.

• Advanced membrane technologies for fine filtration (ultrafiltration,microfiltration).

Dual media filters

Ultrafiltration skids

8914 CHEMISE 4P DESSALEMENT GB.qxd:GB-int-Dessalement 2/10/07 9:19 Page 5

Packaged Solutions

Associated services

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

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, organicmatters) as well as monovalentand bivalent ions.

When membranes separate twowater types, water moleculespass from the less concentratedzone into the more concentratedzone in order to balance ionic forces.

To reverse the natural flow ofwater through the membrane,pressure greater than osmoticpressure has to be applied on theconcentrated solution (i.e. morethan 32 bars for seawater of 40 g/l).

Providing pressures from 70 to 84 bars, 40 to 60% of seawater orbrackish water is converted intofresh water by reverse osmosis.

The influent saline solution is divided into two phases: the permeate (fresh water free of particulates and dissolvedimpurities) and the concentratestream (brine enriched withsuspended and dissolved solids).

Desalator units

8914 CHEMISE 4P DESSALEMENT GB.qxd:GB-int-Dessalement 1/10/07 8:15 Page 6

Veolia Water Solutions & Technologies“L’ Aquarène”1 place Montgolfier94417 Saint-Maurice Cedex - FranceTél. : +33 (0)1 45 11 55 55Fax : +33 (0)1 45 11 55 00 www.veoliawaterst.com

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