treatmentwaterby electromembrane processes

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MEGA is Czech company focused on electromembrane processes like electrodialysis (ED), electrodialysis reversal (EDR) and electrodeionization (EDI). Membrane technologies and relating products offered by MEGA are more known under trademark RALEX®, the official brand of MEGA for Membrane business unit.

MEGA develops, designs and delivers membrane technologies for water treatment and desalination which may represent solutions for industry as well as for the public water utilities in areas suffering lack of suitable water sources or which may treat and recycle the industrial waste water.

The core of the RALEX® technology is high-quality electrodialysis equipment – EDR stack – developed and manufactured by MEGA, technically fully competitive with any other ED modules in the world. Its efficiency and reliability originates from the engineering experience and technical know-how of MEGA technicians and is based on ion-exchange RALEX® Membranes that MEGA produces more than 25 years. The RALEX® Membranes are characterized by their excellent mechanical and electrochemical properties in comparison to other membranes available on the market.

All membrane technologies supplied by MEGA are the result of own research and science work. The company’s main goal is to ensure the satisfaction of the customers by providing them superior technology solutions and services with maximum respect to the environment.

about our company

Selected references – equipment supplier:

� KuibyshevAzot, Togliatti, Russia (2013), 1 440 m3/d (EDR) � Minudobreniya (Rossosh), Rossosh, Russia (2012), 1 440 m3/d (EDR) � Sant Boi – Depurbaix, Barcelona, Spain (2010), 44 000 m3/d (EDR) � Arak, Iran (2010), 4 800 m3/d (EDR) � Abrera, Barcelona, Spain (2008), 240 m3/d (EDR) � GPR, Alberta, Canada (2008), 40 m3/d (EDR) � GEAM, Dolni Rozinka, Czech Republic (2007), 1 440 m3/d (ED) � ZSNP, Ziar nad Hronom, Slovakia (2003), 350 m3/d (ED)

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The RALEX® Membranes are produced in the form of foils composed of fine polymer particles with ion-exchange groups anchoring polymer matrix and reinforced by fitting fabrics, which improves the mechanical properties of the membranes.

A  characteristic feature of ion-exchange RALEX® Membranes consists in the functionality of ion-exchange groups, which are covalently bound to polymer skeleton. The charge of bounded ions in the membranes is balanced by equivalent charge of so called counter ions. If polymer is placed in water solution, it swells and becomes pliable. In the swelled polymer, ions may move in a free way by a diffusive mechanism or by action of the electric field. The membrane behaves like ion conductor in the electric field and transmits ions of the charge with high selectivity.

HeterogeneouS ion-excHange raLex® membraneS

tHe SucceSS of tHe company mega on tHe fieLd of eLec tromembrane proceSSeS iS

baSed on own deveLopment and produc tion of aLL baSic partS of eLec trodiaLySerS

and eLec trodeionizerS. fundamentaL component, tHe raLex® membraneS, are

HeterogeneouS ion-excHange membraneS, proudLy produced by mega in tHe

czecH repubLic Since 1985.

benefits of raLex® membranes:

� Excellent mechanical properties and size stability � Mono-, bi-, trivalent ions removal � High permselectivity P [%]>90 � Chemical resistance in pH range 1–14 allows to use strong lyes and acids for CIP � Tolerance to free residual chlorine up to 1 mg/l as well as to chloramines and

chlorine dioxide � Low electric resistance � Simple handling and transport � Long lifetime

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Under the influence of the electric field the negatively charged anions pass through the anionic membranes but cannot pass through cationic membranes and hence the anions are concentrated in concentrated channel. Similarly cations pass through cationic membrane and are trapped in the concentrate channel on the other side. This results in concentrated and diluted solutions being created in the channels between the alternating membranes.

What is Electrodialysis Reversal?

A continuous self-cleaning electrodialysis process by means of periodic reversal of the DC polarity and switching concentrating and diluting flow streams.

Basic modes of electrodialysis in water treatment:

BATCH: for low capacity projects where high desalination degree and high concentrated brine is required. Usually two feed tanks for batches switching are used. Typically feed water salinity approx. 15–40 g/l.

FEED & BLEED: specific for industrial waste water processing, typical feed salinity 15–40 g/l. High concentrated brine (up to 150 g/l) can be achieved.

ONE-PASS (SINGLE): for large scale application in water desalination and water reuse. Usual salinity of feed up to 4 g/l. Feed water goes through stacks only one time.

eLectrodiaLySiSproceSS

eLec trodiaLySiS iS an eLec tric fieLd gradient driven proceSS enabLing Separate

mineraL mat terS from feed water SoLution wHiLe moving diSSociated ionS

tHrougH ion SeLec tive membraneS and forming t wo different fLowS – deSaLted

fLow DILuATE and concentrated fLow CONCENTRATE (BRINE) .

Na+Na+ +

Cl-

Cl-

Na+

Cl-

Cl-

Cl-Na+

Na+

Na+

Na+

-

Cl-

Cathode (-)

Anode (+)

Cation-Transfer Membrane

Cation-Transfer Membrane

Anion-Transfer Membrane

Demineralized Product

Concentrate

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Robust horizontal high capacity EDR-III electrodialyser is designated for one-pass systems. Operational flow-rate up to 45 m3/h, by default fitted by 500–600 membrane pairs. Electrodialysers for pilot units and small capacity units begin on 100 membrane pairs. Standardly equipped with TiPt electrodes for polarity reversal.

Vertical EDR-II electrodialyser is especially designated for processing of water solutions with higher salinity in batch or feed & bleed modes. Operational flow-rate up to 12 m3/h, by default fitted with 200–250 membrane pairs, polarity reversal option.

eLectrodiaLySerSraLex®

tHe baSic buiLding bLock in wHicH eLec trodiaLySiS proceSS runS iS referred to

aS ELECTRODIALySER . Standard induStriaL raLex® eLec trodiaLySer for water

treatment containS up to Six Hundred ceLL pairS and iS bound togetHer witH

titanium / pLatinum eLec trodeS on tHe outSide for poLarit y reverSaL.

main parts:

� Tightening boards with built-in collectors and electrodes � Heterogeneous RALEX® Membranes and spacers � Tie-rods � Robust stainless steel rack

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water treatment by eLectrodiaLySiS

MEGA SUPPLIES ROBUST ELECTRODIALySIS SySTEMS FOCUSED ON DIFFICULT-TO-TREAT wATERS wITH AIM TO ACHIEVE LOw VOLUME OF CONCENTRATE AND THUS MINIMIZE wASTE. OUR ELECTRODIALySIS IS ALSO PREFERRED IN PROJECTS AIMED TO OBTAIN HIGH CONCENTRATED BRINE AS THE MAIN PRODUCT (CONCENTRATION PROCESSES OF ELECTRODIALySIS).

features & benefits

� High water recovery � High concentrated brine � Less susceptibility to organic fouling � Higher resistivity against risk of scaling � RALEX® Membranes can be CIPed in pH range 1–14 � Tolerance of RALEX® Membranes to free residual chlorine � Silica does not affect performance of electrodialysis � Membrane regeneration by polarity reversal (EDR) � Longer membrane life in comparison with RO modules

typical ed/edr applications

� water reuse of pretreated municipal waste waters to produce water for irrigation � Recycle of industry effluents to reuse it back in a process – recycling of cooling

tower blowdown, preparing cooling tower make up… � Treatment of surface waters with variable feed quality as river waters � Desalination of well waters in aim to reduce dissolved solids as nitrates, fluorides,

sulphates… � Desalination of tailing ponds after mining � Desalination of high silica waters � Further treatment of RO retentate

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Electrodeionization, similar to electrodialysis, is a process which uses an electrical potential difference as the driving force. In EDI ion-selective membranes are combined with ion-exchange resins to form cell pairs consisting of concentrate and diluate compartments. An MPure™ EDI stack consists of multiple cell pairs sandwiched between two electrodes inside a rugged structural enclosure.

HigH purity water production witH mpure™ eLectrodeionization

MEGA OFFERS ELECTRODEIONIZATION FOR RO PERMEATE POLISHING TO PRODUCE HIGH PURITy wATER. EDI EFFECTIVELy REPLACES MIXED-BED ION EXCHANGE RESIN TECHNOLOGy wITHOUT THE USE OF HAZARDOUS REGENERATION CHEMICALS.

applications for edi

� Power industry – high pressure boiler feed water make-up and water for injection into turbines (NOX control)

� Electronics and Semiconductor industry – high purity rinse water production

� Oil & Gas and Chemical industry – boiler feed and process water

� Pharmaceutical, Automotive and Photo Voltaic industry – process and rinse water

features & benefits of edi

� No chemicals are required for regeneration; resins are regenerated continuously by an electric current resulting in consistent high pure water quality

� No bulk chemical storage or waste neutralization is required - environmentally friendly and sustainable process

� Modular equipment with small footprint at all flow rates � Simple and automatic process – no need for operators � Excellent ion removal at high recovery � Robust and reliable system design � Low operating and maintenance costs

� INDUSTRIAL WASTE WATER � COOLING MAKE UP & BLOW DOWN WATER � RO BRINE CONCENTRATION � IRRIGATION � DRINKING WATER

p r o c e S SeLectrodiaLySiS

we are innovative and Leading SuppLier of eLectromembrane proceSSeS, providing Superior SoLutionS and ServiceS witH maximum reSpect to tHe environment.

official trademark of company meGa for membrane processes

mega a.s., Straz pod ralskem, czech republic +420 487 888 300 +420 487 888 302 sales@mega.cz

www.ralex.eu

eLectrodiaLySiS couLd be