An RO System Without Wastewater?

Why does an RO system discharge water?

The principle of reverse osmosis is to force a concentration imbalance between two solutions separated by a semipermeable membrane.

This necessarily produces a more concentrated solution that must be discharged to keep an RO system operating.

Because the pores in our RO membranes are as small as a water molecule (0.1 nm), our RO systems necessarily discharge 50 to 70 % of the water treated. This is a mark of quality!

How to limit wastewater

Nevertheless, there is a way to limit the amount of water discharged by an RO system. It involves operating it in a semi-closed loop.

How do you do this? Simply feed the concentrated water back into your RO system's inlet to filter it again, several times. This allows you to drastically reduce the amount of water discharged.

Caution: Each time the water passes through the RO system, its concentration of undesirable substances increases. However, there is a concentration limit that must not be exceeded. It all depends on your equipment; this limit can be extremely high in a specialized industrial installation, but for a residential or professional RO system, it is around 1,000 ppm (equivalent to 1 g of residue per liter of water).

Technology without wastewater: ultrafiltration

If you cannot set up this semi-closed loop, rest assured: a m3 of water in France costs an average of 3 euros. The additional water consumption caused by an RO system over a year for a household of 4 people therefore costs around ten euros. Of course, this figure only applies if you limit the use of your RO system to drinking and cooking. For all other household uses, we offer a filtration solution without wastewater: ultrafiltration!