Gypsum (CaSO₄) removal from acidic industrial wastewater

Reduce calcium sulphate discharge, stabilise operations and cut OPEX

Did you know?

ED is suitable for strong and weakly acidic feeds.

Advanced electrodialysis provides industries with means of minimizing waste or concentrating precious ingredients.

Extensive R&D is the key to continous innovation and manufacturing of our own membranes, modules and units.

System design is based on 30+ years of industrial experience. MPure™ Design software helps customers to evaluate possible different setups.

Advantages of MEGA electrodialysis in ZLD processes

How it works

MEGA’s electrodialysis with RALEX® ion-exchange membranes selectively separates ions to reduce sulphates and TDS while minimising scaling risk and enabling water reuse. For maximum impact, place ED before neutralisation, where it recovers 60–80% of water and significantly reduces acidic concentrate volumes.

What we deliver

ED stages engineered for acidic wastewater sulphate control with RALEX® membranes
Pre-neutralisation integration to boost upstream performance and reduce downstream load
H₂SO₄ concentration (for strong acid streams) to enable acid reuse and lower discharge
Process support & optimisation for stable, low-scaling operations in existing plants

Where it fits (applications)

Surface treatment & plating – lower CaSO₄/TDS in neutralised effluent; reduce dilution; eliminate scaling.
Chemical processing – relieve hydraulic overload, optimise gypsum precipitation; achieve ZLD/ZW with thermal steps.
Metallurgy & mining – reduce sulphate and metal contamination in wastewater.
Pulp & paper – increase water reuse and reduce chemical sludge.
Biological WWTPs – improve economics by eliminating gypsum scaling and raising yields

Typical implementation

Audit & feasibility using your wastewater data and operating goals.
ED placement before neutralisation to minimise downstream load and scale risk.
Optional acid concentration for strong acid feeds (H₂SO₄ reuse).
Integration with existing lines (incl. thermal steps for ZLD/ZW where relevant).

MEGA Electrodialysis zero liquid discharge plant

Why MEGA’s solution

High sulphate removal efficiency (prevents CaSO₄ saturation issues)
Scaling prevention & process stability (less fouling, fewer outages)
No additional chemicals needed (cleaner operation, lower sludge)
Significant cost savings via lower TDS discharge and reduced maintenance
Seamless integration with existing treatment systems
Turns waste salts into products (gypsum and mixed salt streams)

FAQ

Do we need extra chemicals with ED?: No, ED removes sulphates without additional chemicals.
Where should ED sit in my process?: Before neutralisation: that’s where it recovers 60–80% water and shrinks acidic concentrate volumes.
Can ED help reach ZLD/ZW?: Yes, when paired with thermal treatment, ED has enabled ZLD/ZW in practice.
Are there usable by-products?: Yes, 95%-pure gypsum (90% precipitation efficiency) and a mixed salt with 79% NaNO₃ predominance, both with practical uses.