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Process Technology

Salt Recovery & Crystallisation Systems

Recover valuable salts from high-TDS industrial wastewater through evaporation, crystallisation, and solid-liquid separation — turning waste into byproducts.

What is Salt Recovery?

High-salinity industrial wastewater from food processing (cheese brine, pickle liquor), chemical manufacturing, and water treatment (RO concentrate) contains recoverable salts. Rather than disposing these as hazardous waste, salt recovery uses thermal or mechanical evaporation to concentrate brine, followed by crystallisation and separation to produce purified salt. This reduces disposal requirements, generates output from salt sales, and enables zero-liquid-discharge (ZLD) systems.

Byproduct Output

Recovered NaCl, CaCl2, and mixed salts sold for road de-icing, chemical feedstock, or agriculture.

Waste Reduction

Eliminates liquid brine disposal. Crystallised solids are stable, storable, and transportable.

Energy Integration

Uses waste heat from boilers, WAO, or other processes. MVR evaporators achieve near-ZLD with minimal energy.

ZLD Enabler

Final step in zero-liquid-discharge systems, handling the concentrated brine that membranes cannot treat.

Process Steps

Step-by-step breakdown of the treatment process from influent to effluent.

01

Brine Pre-Concentration

RO or NF concentrates brine to 5-10% TDS, minimising thermal evaporator size. Anti-scalant prevents CaSO4 and CaCO3 scaling.

02

Thermal Evaporation

Multi-effect evaporator (MEE) or mechanical vapour recompression (MVR) evaporator concentrates brine to 20-30% solids. Steam or electricity drives evaporation.

03

Crystallisation

Brine further concentrated in crystallizer (forced circulation or draft tube) until salt crystals nucleate and grow. Mother liquor recycled.

04

Solid-Liquid Separation

Centrifuge or pusher centrifuge separates crystals from mother liquor. Wash water purifies crystal surface. Moisture <3% in product.

05

Product Packaging

Dried salt packaged in bulk bags or sold loose. Purity 85-99% depending on source. Mother liquor returned to crystallizer or disposed.

Typical Performance

85-99%
Salt purity
<3%
Crystal moisture
95%
Water recovery
ZLD
Achievable

Equipment Used in This Process

Explore the equipment components that make this process effective.

Where This Process is Applied

Cheese Brine

Recover NaCl from cheese making brine for reuse or road salt sale.

Chemical Process

Recover valuable salts (Na2SO4, NaCl) from chemical manufacturing effluent.

RO Concentrate

Treat reverse osmosis concentrate that would otherwise be discharged as brine.

WAO Effluent

Recover salts from wet air oxidation effluent after organics destruction.

Related Processes & Technologies

Process Fundamentals & Design

This treatment stage is engineered to achieve specific contaminant removal targets while providing stable, predictable performance across variable inlet conditions. Design parameters are calculated from wastewater characterisation data, regulatory requirements, and site-specific constraints including footprint, energy availability, and operator capability.

Process Optimisation

Design validated by CFD modelling and pilot testing to confirm performance guarantees.

Mechanical Reliability

Equipment selected for 20-year design life with minimal wearing parts and easy access.

Chemical Efficiency

Automated dosing and feedback control minimise reagent consumption and sludge production.

Compliance Assurance

Online monitoring and data logging demonstrate continuous consent compliance.

Design Parameters

Design Flow10 – 5,000 m³/h (application specific)
Inlet VariabilityDesigned for 1:3 peak-to-average flow ratio
Removal Efficiency85 – 99% depending on target contaminant
Hydraulic RetentionCalculated from kinetic constants and safety factors
Power Consumption0.5 – 5.0 kWh/100 m³ (process dependent)
Chemical DoseAuto-controlled based on online analysers
Sludge Production0.2 – 1.5 kg DS/kg contaminant removed
MaterialsSS304, SS316L, or carbon steel with coating

Integration with Treatment Train

No treatment stage operates in isolation. This process is designed to receive conditioned influent from upstream stages and deliver effluent quality suitable for downstream processes. Hydraulic and organic loading rates are balanced across the complete treatment train to prevent bottlenecking and ensure overall plant efficiency. Our engineers model the complete flowsheet to optimise Capital expenditure and Operating expenditure across the plant lifecycle.

Upstream Protection

Screening, equalisation, and pre-treatment protect this stage from damage and overload.

Downstream Conditioning

Effluent quality ensures downstream biology, filtration, or disinfection performs optimally.

Recycle Streams

Reject streams, filtrate, and centrate are routed back to appropriate upstream points.

Need This Process for Your Application?

Our engineers design and commission complete treatment systems including all equipment, automation, and commissioning support.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.