VMD · Technology
Vacuum Membrane Distillation
Vacuum membrane distillation drives separation with a vapor pressure gradient instead of a hydraulic one. A vacuum on the permeate side pulls water vapor through a hydrophobic membrane, leaving everything that is not volatile behind. The result: recovery rates up to 95% on feeds that defeat reverse osmosis, with one-third the energy of conventional evaporation.
What it solves
Performance you can size against.
The outcomes below come from commissioned systems and verified pilots, not theoretical limits. Every number is independently testable on your own feed.
- Maximum feed TDS
- Up to 250,000 mg/L
- Far beyond the 60,000 to 80,000 mg/L practical limit of reverse osmosis.
- Water recovery on tested feeds
- 85 to 95%
- Approaching ZLD without the energy of phase change.
- Operating temperature
- 60 to 80°C
- Low-grade heat works, including waste heat from upstream processes.
- Footprint
- 1/3 of evaporators
- Skid-mounted modules that retrofit into existing facility envelopes.
How it works
The working principle.
A hot, salty feed flows through the lumen of hydrophobic hollow-fiber or flat-sheet membranes. Vacuum on the shell side drops the vapor pressure, drawing water vapor through the membrane pores while liquid water and dissolved solids are blocked by the membrane's hydrophobicity. Vapor condenses downstream as clean distillate. Salts, metals, organics, and suspended solids stay in the brine, which can be cycled back through the loop until the desired concentration is reached.
Performance envelope
Specs and operating range.
For preliminary sizing only. Production sizing is always validated against your specific feed.
- Recovery
- 85 to 95%
- Maximum feed TDS
- 250,000mg/L
- Permeate quality
- <10mg/L TDSIndependently verified on tested feeds.
- Operating temperature
- 60 to 80°C
- Operating pressure
- Vacuum, 5 to 50mbar
- Specific energy
- 150 to 250kWh/m³Total process energy without heat integration; compared to 250 to 600 kWh/m³ for evaporation. Heat-integrated packages such as AQUA-SEP® run at roughly 69 kWh/m³ total.
- Membrane life (typical)
- 3 to 5years
- Footprint per m³/day
- 1.5 to 3m²
How we compare
VMD vs the alternatives.
Where Vacuum Membrane Distillation wins, where it does not, and where the alternatives are honestly the better fit.
| Trait | VMD | Reverse Osmosis | Mechanical Vapor Recompression |
|---|---|---|---|
| Maximum feed TDS | Up to 250,000 mg/L | 60,000 to 80,000 mg/L | Up to 350,000 mg/L |
| Specific energy | 150 to 250 kWh/m³ total (no heat integration); ~69 kWh/m³ in heat-integrated packages | 3 to 8 kWh electrical/m³ (low TDS only) | 20 to 35 kWh electrical/m³ |
| Tolerance to fouling | High; hydrophobic membrane resists organic fouling | Low; pretreatment cascade required | Moderate; scale management critical |
| Capex per m³/day capacity | Mid-range | Low (when feed permits) | High |
| Best fit | High-salinity, high-organic, ZLD-bound feeds | Low-TDS feeds with stable composition | Concentrated brines ahead of crystallization |
Maximum feed TDS
VMD
Up to 250,000 mg/L
Reverse Osmosis
60,000 to 80,000 mg/L
Mechanical Vapor Recompression
Up to 350,000 mg/L
Specific energy
VMD
150 to 250 kWh/m³ total (no heat integration); ~69 kWh/m³ in heat-integrated packages
Reverse Osmosis
3 to 8 kWh electrical/m³ (low TDS only)
Mechanical Vapor Recompression
20 to 35 kWh electrical/m³
Tolerance to fouling
VMD
High; hydrophobic membrane resists organic fouling
Reverse Osmosis
Low; pretreatment cascade required
Mechanical Vapor Recompression
Moderate; scale management critical
Capex per m³/day capacity
VMD
Mid-range
Reverse Osmosis
Low (when feed permits)
Mechanical Vapor Recompression
High
Best fit
VMD
High-salinity, high-organic, ZLD-bound feeds
Reverse Osmosis
Low-TDS feeds with stable composition
Mechanical Vapor Recompression
Concentrated brines ahead of crystallization
Where it's deployed
Industries that use this process.
Vacuum Membrane Distillation fits some sectors better than others. The industries below are where we have shipped multiple systems.
Oil, Gas & Energy
Process equipment, packaged plants, and patented separation for upstream, midstream, downstream, and energy.
Learn more
Mining
Process plants and patented separation for tailings, brines, lithium, and ZLD.
Learn more
Industrial Manufacturing & Environmental
Process equipment, packaged plants, and patented recovery for manufacturing, water reuse, and emissions control.
Learn more
Engineering FAQ
Questions engineers ask.
The questions we hear weekly. If you have a different one, send it with your consultation request and we will answer it directly.
Can VMD handle silica?
What about feeds with hydrocarbons or oil?
How does VMD compare to reverse osmosis on cost?
Can the system run on waste heat?
What is the membrane lifetime?
Have a feed that VMD
might fit?
We will pilot before we promise. Send us a sample and a target outcome. If the technology fits, we will tell you what to expect; if it does not, we will tell you that too.