Reverse Osmosis & Thermal Desalinationfor drinking water, industrial water & water recycling

Desalination technologies

Desalination

Finding new approaches through R&D On the strength of our extensive experience, our current focus is on the development of mem-brane distillation (MD). Membrane distillation is a thermally powered separation technology based on hydrophobic membranes, which allows higher concentration efficiency at lower cost.

Pilot tests are currently under way with the aim of studying concentration performance in the case of various effluents (such as produced water) and brines (such as concentrates from rec-lamation plant ROs). In this context, the development and design of an ideal pre-treatment for MD is extremely important.

Moreover, progress has been made in the area of minimising brine return volumes and this constitutes a step towards zero liquid discharge (ZLD).

WABAG - for over 90 years a synonym for innovative and successful water engineering solutions.

WABAG is an international supplier of water and wastewater treat-ment systems for both municipal and industrial segments. It is one of the innovative leaders in this field and in particular, is one of the few companies in the world to offer a comprehensive spectrum of technologies for the desalination of sea and brackish water:

�� Reverse osmosis�� Thermal desalination (MED, TVC, MED-XL™ and XXL™, MVC, MSF)�� Electrodialysis (ED)�� Ion exchange (IX)

With more than 30 years of desalination experience, WABAG has designed and built over 100 plants worldwide.

At present, the widely preferred technologies for the desalination of sea and brackish water are: �� Membrane technology: reverse osmosis (RO)�� Thermal methods: multi-effect distillation (MED)

These technologies can be utilised for both the production of po-table water and industrial process water, and form the basis for optimum and customised solutions. Desalination technologies are also of increasing importance in the field of water recycling sys-tems and demineralisation, while the employment of membrane technologies such as reverse osmosis allows the reuse of indus-trial effluents as highly-purified process water, e.g. as boiler feed water.

What makes WABAG a preferred partner?�� A comprehensive desalination technology portfolio

�� Proven process know-how and expertise as well as an under-standing of entire systems

�� The provision of complete solutions: EP, EPC, DBO, BOOT

�� In-house R&D centres in India, Austria and Switzerland, which guarantee the optimisation and further development of desali-nation technologies

�� Experience as a desalination plant operator

�� A multinational presence and long-term experience

�� The integration of desalination plants with water reclamation systems

�� Freedom of choice on the most suitable membrane systems

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Reverse Osmosis or Thermal Desalination

The larger the salt content of the untreated water and the greater the required degree of purity at the desalination output, the higher the energy costs.

In the past, reverse osmosis installations required sizeable amounts of electrical power. However, owing to increased energy optimisation, these processes have now become far more cost-efficient. In today’s world, RO is indispensable for the supply of potable water in countries lacking adequate ground or surface water resources. It has emerged as the most economic solution where residual steam is unavailable as an energy source.

By contrast, thermal seawater desalination using residual steam as an energy source is the most appropriate solution in power plants and offers major O&M savings. Thermal MED in-stallations, for example, are operated with low pressure exhaust steam or with output steam from steam turbines. For steam pres-sures above 2 bar, thermal MSF would then be appropiate. When such energy is available this process is most suitable.

REVERSE OSMOSIS

THERMAL DESALINA-

TION

WABAG is one among the very few companies in the world to offer both technologies on standalone or hybrid basis.

Al Ghubrah, Seawater Intake sinking

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RO – the advantages:

�� Proven and time-tested technology�� Relatively low investment costs as compared to thermal methods�� Application flexibility - from very small (< 100 m3/d) to large installations (> 100,000 m3/d)�� No cooling water requirement�� Less energy consumption than with an MED system

RO is a pressure-driven process. Saline water is forced through semi-permeable membranes under pressure, thereby separating the saltwater into a freshwater stream (known as permeate) and a brine stream (concentrate).

Typical process steps in an RO system:

1 Pre-treatment (protecting the RO membranes)2 High Pressure Pumps3 Energy Recovery system4 RO Membrane Modules5 Concentrate discharge6 Post-treatment (remineralisation, disinfection)

The recovery percentage of purified water de-pends upon various factors that include mem-brane size and internal structure, temperature, operating pressure and membrane surface area.

Due consideration given to the economic factors such as:�� Energy recovery�� Membrane durability�� Chemical consumption�� Process automation

Reverse Osmosis Desalination

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3

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4 6Raw water Product water

Nemmeli, IndiaSeawater RO, 100,000 m3/d

35Al Wasia, Saudi Arabia Brackish water RO, 200,000 m3/d

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Saving energy & costs

Employing pressure exchanger systems.

The RO process does not require thermal energy, but needs elec-trical power mainly due to the high pressure pumping required to obtain flow through the RO membranes. Brine energy recovery systems have also been optimised in order to reduce energy con-sumption and have proved to be highly successful.

Complete and Exclusive

Customized solutions

WABAG supplies RO plants for various types of raw water such as seawater, brackish water and industrial effluents. As a provider of end to end solutions, WABAG delivers the entire process from the raw water onwards, including deep seawater intake and outflow structures to the post-treatment of product water and product water pumping stations.

On the strength of its experience in design, construction and op-eration of plants of varying sizes, WABAG offers economically ad-vantageous and technically proven solutions for every application.

Highly effective pre-treatment systems are extremely important

From filtration to micro- and ultrafiltration

WABAG lays a special emphasis on efficient pre-treatment. In that, apart from conventional filtration technologies, highly effec-tive micro- and ultrafiltration systems are employed.

For example, WABAG designed and built the first plant in Oman (Duqm, Al Wusta region) to use microfiltration units for pre-treat-ment and subsequently this successful combination was also used in the desalination plant for the new Sohar International Port (start-up 2013), where an in-line RO system was successfully ex-ecuted.

The Nemmeli RO-drinking water plant in Chennai, which is one of the largest plants of its kind in India, employs ultrafiltration mem-branes for highly effective pre-treatment upstream of the RO sys-tem.

WABAG is an established name in various pre-treatment tech-nologies. 5 Duqm SWRO, Oman

6,000 m3/d, Pre-treatment (microfiltration)

Al Kharj BWRO, Saudi Arabia50,000 m3/d, Pre-treatment

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Combination of microfiltration and reverse osmosis desalination.

An integrated solution.

Client: Majis Industrial Services SAOCContract type: DBO - Design-Build-OperateCommissioning: 2013

Raw water: seawaterProduct: potable water and process waterCapacity: 20,000 m3/dProcess: reverse osmosis with self-cleaning filters and membrane pre-treatment

Microfiltration-based Inline RO system - reduced CAPEX, OPEX and footprint.

Main parameter: 44,000 ppm TDS Plant recovery: 40% Process water quality: < 25 ppm TDSPotable water quality: 120-600 ppm TDS

Completion of a reverse osmosis (RO) based seawater desalina-tion plant producing 8,000 m3/day of industrial process water and 12,000 m3/day of potable water, thus contributing substantially to a continuous water supply at Sohar Industrial Port Area, Sultanate of Oman.

Sohar International Port SWRO, Muscat, Oman Most modern desalination plant for drinking and industrial water production.

Best practice references

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Objectives�� Ensuring reliable operation even during difficult raw water intake conditions such as red seawater tides�� Continuous RO water production�� Low life cycle costs

SEAWATER INTAKE SYSTEMA 2.6 km, 800 mm diameter pipeline feeds the plant through a tap off from an existing cooling water pump manifold. Two 300 micron automatic self-cleaning filters are installed midway through the pipeline.

PRE-TREATMENTMicrofiltration to handle inlet TSS up to 80 ppm obtaining at the output SDI of less than 1 (input SDI 35+). Configuration: 7 Skids, each with 80 modules and 420 m3/h capacity.

DESALINATION Sea- and brackish water RO – 3 units: 12,000 m3/d, double-stage Seawater RO – 2 units: 8,000 m3/d, single-stage

ENERGY RECOVERY SYSTEMPressure exchanger

POST-TREATMENT1. Post-treatment for pH adjustment and disinfection of potable water.2. Neutralization system for brine.

Reduced energy consumption With its hybrid membrane system (high- and low-rejection) WABAG has met the stringent quality of product water with op-timized energy consumption. Energy recovery devices are de-ployed to extract power from the SWRO reject stream.

Modern design reduces costsIn general terms, the employment of a modern process design and in particular the direct combination of microfiltration as a pre-treatment with reverse osmosis plant without additional cartridge filters and feeding pumps between MF and RO, has resulted in lower investment and operational costs. In addition, the plant foot-print is smaller than that of conventional RO desalination plants.

Further references

SEAWATERMuscat, Oman

OPWP Al-Ghubrah: 192,000 m3/d, potable water, EPC, start-up: 2015

Ras Laffan, Qatar

PUNJ-LLOYD, 12,000 m3/d, process water, EP, start up: 2015

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Clean drinking water for one million people in Chennai.

A complete solution.

Client: Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB)

Contract type: DBO - Design-Build-OperateStart-up: 2013 O&M period: 2014-2021

Raw water: seawaterProduct: potable water Capacity: 100,000 m3/d

Main parameter: 41,900 ppm TDS Plant recovery: 45.4% Potable water quality: <500 ppm TDS

From the sea to the tap. Using technological competence and professional management.WABAG was awarded a contract for the design, construction and operational management of one of India‘s largest seawater RO desalination plants. The plant was built on a 16-hectare site 40 km south of Chennai and converts seawater into fresh potable water, which is supplied to one million people in the city’s southern suburbs.

SEAWATER INTAKE SYSTEM�� Pipeline (1,600mm diameter, HDPE, length: 1,050m, sea-side depth: 14.1m)�� Maritime intake filter �� Intake chamber (upflow filter and sedimentation tank)

PRE-TREATMENT�� Disc filters, ultrafiltration

ENERGY RECOVERY SYSTEM�� Pressure exchanger

DESALINATION�� Reverse osmosis (spiral-wound polyamide)

POST-TREATMENT�� Remineralisation system: carbon dioxide absorber and lime-stone filter�� Degasser tower

Nemmeli SWRO, Chennai, India Reverse osmosis to boost drinking water supply volumes.

Further references

BRACKISH WATERAl Wasia, Saudi Arabia: 200,000 m3/d,

potable water, start-up: 2010Al Kharj Saudi Arabia:

50,000 m3/d, potable water, start-up: 2009

SEAWATERDuqm, Oman: 6,000 m3/d,potable and process water,

DBO, start-up: 2010

Best practice references

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Highly efficient water recycling plant for a refinery expansion.

A sustainable solution.

Client: Indian Oil Corporation Ltd. (IOCL)Start-up: 2006 Raw water: secondary refinery effluent and various refinery/petrochemical process effluentsProduct: boiler feed water and process water for PTA production Capacity: 21,600 m³/day

Technology: multi-stage treatment including ultrafiltration and reverse osmosisPlant: water recycling plant

Main parameter: TDS: 1,786 mg/l, silica: 98 mg/l, COD: 150 mg/lPlant recovery: 90%

WATER QUALITY after RO: after demineralisation:TDS: 12 mg/l TDS: < 0.05 mg/lsilica: 0.09 mg/l silica: 0.007 mg/lCOD: 0

90% water recovery. Completion of a tertiary treatment plant (TTP) for the refinery ef-fluent recycling for the Indian Oil Corporation Ltd., in Panipat, In-dia with the aim of achieving zero liquid discharge in combination with the recycling of wastewater for reuse as boiler feed make-up water. It is the first plant of its kind in India.

Sustained focus on zero liquid discharge (ZLD).

�� High-rate clarification�� Pressure sand filtration�� Ultrafiltration (UF) – pressure-driven, hollow fibre system�� Cartridge filter�� Reverse osmosis (RO) – two-pass system in combination with a brine concentrator, 3 stages �� Degasser tower�� Demineralisation: RO permeate is polished by mixed bed, ion exchange filters

RO for water recycling at the Panipat Refinery, India Closing the water cycle.

Further references

Paradip Refinery, Orissa, India: 54,000 m3/d, process water, start-up: 2015

Panipat Naphta Cracker Project, India: 20,900 m3/d,

boiler feed water, start-up: 2009

Essar Oil, India: 9,600 m3/d, cooling and

boiler feed water, start-up: 2011

Best practice references

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Achieving synergy - MED The MED desalination process is normally used for medium-sized and large-scale thermal desalina-tion plants where thermal energy is available in the form of low-pressure steam (≥ 0.3 bar abs.) or waste heat, e.g. in combination with thermal power plants or industrial complexes. It therefore represents the most eco-nomic distillation process from an en-ergy efficiency perspective.

Main advantagesThe MED process operates at low temperatures with high thermal effi-ciency, providing:�� Low thermal energy consumption�� Low operating costs

MED-TVC - enhanced efficiency Standard MED plants are equipped with thermal vapour compressors for enhanced efficiency.

As a rule, the TVC desalination process is employed for small to large-scale thermal desalination plants where thermal energy in the form of medium pressure steam (>3 bar) is available, e.g. in combination with thermal power plants or industrial complexes and this results in low opera-tional and investment costs.

Therefore, from cost-efficiency standpoint, TVC distillation is the most advantageous, steam-heated process for medium-sized plants.

Main advantagesThe TVC process operates at low tempera-tures with high thermal efficiency, providing:�� Small to large train sizes�� Low investment costs

Thermal Desalination technologies

Multi-effect distillation

Selected references

AVR, Rotterdam, The Netherlands: 24,000 m3/d,

process water CMI, Marmara, Turkey:

3,360 m3/d, process water

Selected references

Tobruk, Libya: 13,333 m3/d, potable water, start-up. 2016

Suralaya, Indonesia: 6,000 m3/d, process & potable water, start-up: 2010

Rembang, Indonesia: 6,000 m3/d, process & potable water, start-up: 2010

GMDC, Kutch, Gujarat, India: 2,400 m3/d, process water, start-up: 2006

Benghazi North, Libya: 4,800 m3/d, process water, start-up: 2005

Thermal desalination (multi-effect distil-lation) takes place in a series of vessels (effects) in which the principle of con-densation and evaporation at reduced ambient pressure is applied. This per-mits the saline water to undergo boiling without the need to supply additional heat after the first effect.

Thermal desalination – the advantages �� Stable and proven process�� Minimal or no need for pre-treatment�� High output water purity level (≤ 10 ppm TDS)�� Ideal in combination with power plants �� Simple operation with low mainte-nance costs

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MED-MVC - the stand-alone solution Where an external steam source is unavailable for heating, standard MED plants are equipped with mechanical vapour compressors (MVC). These pro-vide heat for water evaporation through mechanical steam compression.

The MED-MVC desalination process is normally used for small to medium scale thermal desalination plants where thermal energy is unobtainable. The mechanical compressor is electrically or diesel driven.

Main advantages�� No need for external thermal energy�� A robust process

Multi-stage flash (MSF) - large-scale thermal desalination technology MSF - the big solution. The MSF de-salination process is utilised mainly for large-scale, thermal desalination plants where thermal energy in the form of low-pressure steam (>2 bar) is avail-able, e.g. in combination with thermal power plants or industrial complexes.

Saline water is heated by steam and then fed into a series of vessels (effects) where reduced pressure leads to imme-diate boiling (flash) without the need for additional heat.

Main advantages�� Large train sizes�� Low energy consumption

MED – XL™ and XXL™ Recently, the capacity of thermal sea-water desalination units has begun to increase considerably. In response to this trend, WABAG has designed and optimised its XL (in the range of 13,500 - 25,000 m3/d) and XXL units (from 25,000 up to 45,000 m3/d).

In these newly developed systems, all the preheaters are enclosed in an extremely compact manner, which not only prevents heat losses, but also guarantees highly efficient operations.

These large units can be built as MEDs or MEDs with thermal vapour compressors (MED-TVC).

Selected references

Burrup Penninsula, Australia: 3,600 m3/d, process & potable

waterCHP, Taba, Egypt:

2,000 m3/d, potable water

Selected references

REFURBISHMENTSKhoms, Libya: 30,000 3/d,

process water, start-up: 2008 Zliten, Libya: 30,000 m3/d, potable and process water,

start-up: 2008

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VA TECH WABAG GmbHDresdner Straße 87-911200 Vienna, Austria Tel.: +43 1 251 05 0contact@wabag.com

VA TECH WABAG LIMITED“WABAG House“No.17, 200 Feet Thoraipakkam – Pallavaram Main RoadSunnambu KolathurChennai 600 117, IndiaTel.: +91-44-3923 2323wabag@wabag.in

WABAG offers sustainable solutions for:

n Drinking water treatment

n Industrial and process water treatment

n Water reclamation

n Sea and brackish water desalination

n Municipal wastewater treatment

n Industrial wastewater treatment

n Sludge treatment

WABAG is one of the world’s most innovative water

treatment companies with know-how in specific techno-

logies and in-house developed processes such as:

n Biofiltration BIOPUR®

n Moving bed biology FLUOPUR®

n Activated sludge Hybrid™, SBR, processes MICROPUR-CAS®

n Membrane bioreactor MARAPUR®, MICROPUR-MBR®

n Membrane filtration RO, MF, UF, NF CERAMOPUR®, CERAMOZONE®

n Denitrification BIODEN®, ENR®

n Oxidation processes ADOX®, BIOZONE®

n Adsorption processes CARBOPUR®, PACOPUR®

n Thermal desalination MED, TVC, MVC, MSF MED XXL™n Fine sieving MICROPUR®

n Deep bed filtration in various designsn Anaerobic sludge digestion

including advanced energy recovery

The WABAG Group represents a leading multinational

player with companies and offices in 20 countries and

a focus on emerging markets in Eastern Europe, Africa,

LATAM, Middle East, South East Asia, China and India.

www.wabag.com

sustainable solutions. for a better life.

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