Project details:
- Client: PWN Technologies
- Location: the Netherlands
- Industry: Drinking water treatment
- Salttech technology: Dyvar® – Dynamic Vapor Recompression
- Pilot setup: Dyvar® Integrated with biological denitrification and nanofiltration
- Objective: Minimize brine volume and product recovery (NaCl and clean water)
- Case study based on Paper: Further Treatment of Ion Exchange Brine with Dynamic Vapour Recompression. E.Vaudevire, E.Koreman, G.Galjaard, R.Trommel, M.Visser
About PWN Technologies
PWN Technologies, a Dutch water technology company and former subsidiary of the PWN drinking water utility, decided to investigate managing spent brine generated from its advanced ion exchange (IEX) process, ‘SIX®.’ This case study highlights how Salttech’s Dyvar® technology enabled PWN to reduce brine volume and recover resources.
Goals For PWN Technologies
To guide design and verify outcomes, PWN defined clear, measurable objectives for integrating Dyvar® with the SIX® ion-exchange process. The targets focus on disposal reduction, water reuse, and salt recovery, with circularity as a core principle. The objectives are:
- Reduce disposal volume and fees: Reduce brine disposal volumes by up to 90%
- Recover components: Recover high-purity NaCl suitable for resin regeneration
- Recover water: Recover clean water for reinjection upstream.
- Reduce footprint: Establish a circular brine treatment loop that reduces the environmental footprint of brine disposal
The brine challenge
The SIX® process effectively removes dissolved organic carbon (DOC) and nitrate from surface water but generates significant volumes of spent brine. PWN sought to reduce the disposal fees and chemical use. Additional goals of the project were to recover NaCl and water for reuse and improve overall process sustainability.
Dyvar® One-step concentration and crystallization
Salttech provided the Dyvar® system, a one-step dynamic vapor recovery technology that combines efficient concentration and crystallization of saline streams. Implemented as a compact, containerized unit, the setup is designed for reliability, corrosion resistance, and hands-off operation.
Salttech’s Dyvar® technology was implemented as final step in the three integrated stages of the project:
- 1) Biological Denitrification (DNF): Removed nitrate from the brine before further treatment and achieved complete nitrate removal with low biosludge production.
- 2) Nanofiltration (NF): Separated monovalent ions (passage of Na⁺, Cl⁻) from divalent ions (rejection of Ca²⁺, SO₄²⁻), enabling partial NaCl recovery and retaining dissolved organic carbon (DOC) and divalent salts.
- 3) Dyvar® Technology: Final concentration and crystallization step that reduced brine volumes by up to 90%, possibly precipitating salts, and recovering clean water; operating efficiently at high TDS with low energy input of 50–60 kWh/m³ condensate.
System performance at a glance
Salttech’s Dyvar® technology delivered strong technical, economic, and environmental results during pilot testing with ion exchange brine. The system enables high recovery of clean water and possibly reusable salts, while significantly reducing disposal volumes and fees.
Key system highlights:
- Operates at high TDS with low energy input
- Selective salt precipitation at different concentration factors
- High-purity NaCl crystals recovered and rinsed for reuse
- Cooling to 5°C enhances NaCl separation from sulphates and carbonates
Economic and environmental benefits:
- Disposal and transport volumes reduced by more than 90% resulting in significant cost reduction
- Clean water recovered for reuse in upstream processes
- Scalable and energy-efficient alternative to conventional evaporation
Ready to take the next step in your brine processing?
Want to explore Dyvar for your site? Or request a bench-scale test for a quick, data-driven feasibility check? Get in touch.
Phone: +31 (0)85 0072 208
Mail: sales@salttech.com
