ZLD is powerful and expensive. A practical guide to deciding whether your site needs it, or just needs high recovery.
The last 5% is the hardest
Taking reuse from 90% to 100% often costs as much as everything before it. Brine concentrators and crystallisers are energy-intensive and demand skilled operation.
When ZLD is right
ZLD makes sense where discharge is impossible or prohibitively regulated, or where the salts themselves have value. Elsewhere, high-recovery RO with responsible brine management is usually the better answer.
Designing for later
If ZLD may be needed in the future, design for it now: leave the footprint, the electrical capacity and the tie-ins.
Keep reading
Reverse osmosis
14 Oct 2026
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Reading the early signs of membrane fouling
Normalised permeate flow tells you more than any alarm. How to spot fouling weeks before it costs you a cleaning cycle.
Water reuse
30 Sep 2026
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The real economics of industrial water reuse
Payback is not just water price. A lifecycle model for reuse that includes risk, permits and the value of supply security.
Engineering
12 Sep 2026
5 min
Why we still build physical models
In a world of digital twins, a white model on a table still catches the clashes and access problems nobody saw on screen.