Desalination & Membrane Water Treatment Equipment worked example

Membrane Fouling Loss with permeate flow lost to fouling of 30 m³ / hr: a worked example

This scenario runs the membrane fouling loss calculation on the strong side: permeate flow lost to fouling of 30 m³ / hr, with every other input held at its documented default. Use it when membrane fouling loss in desalination and membrane water treatment equipment is being quoted and consumables are a real chunk of the cost stack.

The inputs for this scenario

  • Permeate flow lost to fouling: 30 m³ / hr (raised for this scenario; the documented default is 12)
  • Hours run in fouled condition: 8 hr (unchanged)
  • Sale or replacement value of permeate: 3.5 $ / m³ (unchanged)

Working through the calculation

  • Applying the documented formula (Lost permeate volume = permeate loss from fouling × fouled operation runtime) to the inputs above produces each figure below.
  • At this operating point the engine returns 240 units for lost permeate volume, the number this scenario is built around.
  • At this operating point the engine returns 840 $ for fouling-related production loss cost.
  • At this operating point the engine returns 8 hr for fouled operation runtime.
  • At this operating point the engine returns 3.5 $ / unit for value of lost permeate.

How this compares with the baseline

  • Against the tool's baseline example, where permeate flow lost to fouling sits at 12 m³ / hr and the headline result is 96 units, this scenario comes in 150% above the baseline at 240 units.
  • Use it when normalized permeate flow has dropped below baseline and you need to justify the timing of a clean-in-place, element replacement, or pretreatment upgrade. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • Lost permeate volume: 240 units (headline result)
  • Fouling-related production loss cost: 840 $
  • Fouled operation runtime: 8 hr
  • Value of lost permeate: 3.5 $ / unit

Run it with your numbers

  • Every input above is editable in the live Membrane Fouling Loss calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.