Every water treatment system splits its feed into two streams: the clean water you keep, and a concentrated stream that carries away what was removed. The share you keep is called the recovery rate, and it is the number buyers most often want pushed up — and engineers most often want held down. Both instincts are reasonable, which is why it deserves a proper look.
What recovery means in practice
A higher recovery rate means less water is sent to drain, which sounds like pure gain. But everything removed from the feed has to go somewhere, and as recovery rises the leftover stream becomes more and more concentrated. The equipment at the tail end of the system works in progressively harsher water, and at some point minerals start to deposit on surfaces — the water treatment equivalent of kettle scale, except far harder to remove.
Why more is not always better
Pushing recovery up also costs energy: the more concentrated the leftover stream, the harder the pumps have to work against it, and the product quality slowly falls at the same time. Past a certain point you are paying more in electricity and wear to save water that may cost very little. Where the water itself is cheap and discharge is unrestricted, a modest recovery is often the most economical choice. Where discharge is expensive or restricted, a high-recovery design can pay for itself quickly.
Finding the balance
- Start from the water analysis — the water itself sets a hard upper limit
- Price the wastewater: what does each cubic metre of discharge actually cost you?
- Leave a safety margin rather than designing on the theoretical maximum
- Review the setting after commissioning, once the plant’s real behaviour is known
If you are weighing this decision for your own site, send us your water analysis — we will show you where the balance point sits for your specific case.