EDR 101Electrodialysis Reversal I

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Outline

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1. Introduction2. Components of EDR3. Operating Principle4. Advantages/Disadvantages of EDR5. Applications

Saltworks’ micro EDR stack (left) and full scale EDR stack (right)

Introduction

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• EDR = Electrodialysis Reversal

• Transport salt ions from one solution to another solution through ion-exchange membranes under the influence of an applied electric potential current

• Separation is due to charge, not pressure or size differences.

EDR Components

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Cathode

Concentrate ProductProduct Concentrate

Feed FeedFeedFeed

Anode

Anion Exchange Membrane

Cation Exchange Membrane

Anions pass through Cations blocked

Anions blocked Cations pass through

-+

-+

• Water flows parallel to the membranes.

• Positive ions flux through cation exchange membranes towards negatively charged cathode.

• Negative ions flux through anion exchange membranes towards positively charged anode.

• Water does not flux through the membranes.

• Product stream becomes purer while concentrate stream becomes more concentrated with ions.

Operating Principle

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• Polarity reverses periodically to prevent fouling on the membranes

• Product compartments and Concentrate compartments swap

Organic and inorganic fouling removed from membranes by reversed movement of ions

Reversal

Reversal

Operating Principle

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Advantages/Disadvantages of EDRAdvantages• High recovery• Higher brine concentration

achievable as system is not limited by osmotic pressure

• Little to no feed pre-treatment required

• Built in chemical-free scaling and fouling prevention due to periodic reversal feature

Disadvantages• Only removes ions; organics and

colloids not removed• Selection of membranes and

stacks highly dependent on feed water chemistry

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Mining

Brine Management

Acid & Base

Recovery

Agriculture

Food & Beverage

Mining

Brine Management

Acid & BaseRecovery

AgricultureFood &

Beverage

Electrodialysis Reversal

Mine runoffs

Acid rock drainage

Milling waters

Selective recovery

Process waters

Ion exchange resin regeneration

Aluminum anodizing

Acid etching

Metal pickling

Agriculture wastewaters

Phosphogypsum wastewaters

Water softener

Concentrate brine

Inland brackish water

Wine tartaric stabilization

Water recovery, recycling and reuse

Applications

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Saltworks offers five electrodialysis reversal products under the ElectroChem name:

Saltworks’ full scale skidded ElectroChem system (5-50 tonne/day)

Wastewater Desalter

Desalination, wastewater treatment, water purifier/remediation/reclamation

RO Brine Concentrator

Reverse osmosis brine concentrator

Salt Splitter Calcium sulphate, gypsum, water softener, tailings, acid rock drainage

Produced Water Desalter

Polymer, enhanced oil recovery produced water

Acid Recycle System

Sulfuric/hydrochloric/hydrofluoric acids, battery acid, etching acid, aluminum anodizing acids

Applications

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