Osmosis water: what is a domestic osmosis unit used for?

Today, we're going to discuss the usefulness of this device, the domestic water osmosis plantwhich can be found just about everywhere, and which usesreverse osmosis.

WHAT IS AN OSMOSIS UNIT?

An osmosis plant is a device for water purification based on the principle ofreverse osmosis. It uses a semi-permeable membrane to eliminate dissolved impurities, such as mineralsthe heavy metalsand some organic contaminants. This system is often used in homes to improve the quality of tap water, although it is more widespread in industry and laboratories.

WHAT EXACTLY DOES AN OSMOSIS PLANT DO (TECHNICALLY)?

An osmosis unit filters water in three main stages:

Pre-filtration : Removal of solid particles such as sand and sediment, and reduction of certain chemical components in the water, such as chlorine.
Membrane filtration : By exerting pressure on the water, the molecules pass through an ultra-fine membrane that retains ions and other unwanted substances.
Post-filtration : Final adjustment to eliminate odours or improve taste.

However, this process has its drawbacks, notably the high consumption of water to produce a small quantity of purified water. In addition, minerals that are essential to good health (such as magnesium and calcium) are also removed, leaving the water depleted of nutrients. Let's take a closer look at the arguments put forward by osmosis dealers

THE DIFFERENT TYPES OF WATER OSMOSIS PLANT

There are several types of reverse osmosis units for different uses:

Domestic reverse osmosis : Small models designed for domestic use, often installed under the sink.
Tank Osmosis : Practical for storing purified water, but more bulky.
Tankless osmosis systems : More compact, but often with reduced throughput.
Industrial reverse osmosis : Used in laboratories and industry to produce ultra-pure water in large quantities.

Each type of osmosis unit meets specific needs, but their operation remains broadly similar.

THE PROMISES OF THE WATER OSMOSIS UNIT

So no, reverse osmosis systems don't promise anything, we agree ;). But let's go back to the supposed benefits that the installation of a domestic water osmosis unit and its production ofosmosis water are supposed to bring you.

In general, manufacturers put forward the following arguments:

Improved water quality Osmosis units can effectively filter contaminants and impurities from water.
Safe drinking water Osmosis water is healthier for drinking than standard tap water.
Better taste of reverse osmosis water Water filtered by a reverse osmosis system is said to taste and smell better than standard tap water.
Filtration of potentially harmful contaminants By filtering the water in reverse osmosis systems, potentially harmful contaminants such as heavy metals, chemicals, pesticides, drug residues, bacteria and other micro-organisms are eliminated.
Ecological option : By eliminating the need to buy bottled water, osmosis systems are a more environmentally-friendly solution.

Our use of the conditional above should make it clear to you right away that, in our opinion, these arguments are, at best inaccurateat worst, downright fake.

In this article, we'll show you why you don't need a reverse osmosis system in your home.

In addition, we will be looking at solutions for improving the quality of tap water, such as tap water purifiers that use UV-A radiationthat exist and at a lower cost!

THE RECURRING COSTS OF A DOMESTIC OSMOSIS PLANT

First of all, let's talk about a strong trend in the current market for products sold to treat water and improve its quality: we are seeing a steady stream of recurring revenue products.

Filter jugs, water softeners, osmosis units and many others, which make us buy consumables (mostly filters) on a regular basis.

Read more: Filter carafes: a good idea?

The same applies tomineral water. These are always recurring purchases that will create an additional budget in your household.

INSTALLING A WATER OSMOSER: A substantial cost

To illustrate this further, let's take a look at a basic package, available on the market for around €250.

Components of the osmosis unit

Bear in mind that a standard osmosis unit costs more in the 1500€So this is a 'first prize'.

So, let's take a closer look: a pre-filter sediment filter type, a reverse osmosis membrane guaranteed to last 12 months at €70 for replacement, a afterfilter activated carbon, a 6l tankand a low-flow tap.

Installation

If you can install it yourself, great, if not approximately double the price of the appliance to include installation, i.e. more than €500 installed.

Here's a video showing you how to install an under-sink reverse osmosis unit. It's not that simple!

The manufacturer of this particular reverse osmosis unit claims that its membrane lasts 2 years, but in the comments on a major retail website, a customer mentions that the actual duration is halvedone year.

To sum up, you have to change the filters every six months, i.e. €100 per year, and €70 of membrane, which gives you over three years: 500+300+210= 1010€. In addition, you will continue to pay annually 170€provided your water is not too "hard", in which case the manufacturer recommends that you add a "hardener". water softener before the osmosis plant.

Above a water hardness of 15°F (water hardness is measured in French degrees (°F)), we strongly advise you to install a water softener to extend the life of the system and protect it from limescale.

Finally, you also need to take into account the energy cost of running the appliance's electric pump, as well as the extra water consumption (on average), 3 litres of water are rejected for 1 litre of osmosis water).

Okay, we get it, it's expensiveand capriciousand, roughly speaking the job of a carafe filter equipped with an active carbon filter and a 6-litre tank.

So what's in it for us?

WHAT ARE THE HEALTH BENEFITS OF OSMOSIS WATER?

No if your water is drinkable. The only benefit is to remove the salt that the softener would have added.

Elimination of essential minerals

An osmosis plant is originally a product for the Nasa space stations or boatsThe osmosis process can be used to recycle salt-laden water or urine, for example. But as salt is regulated in drinking water, there is no point in osmosing tap water.

Basically, this is how osmosis water is produced ultra-processed, "deadunfit for consumption, and therefore "unfit for human consumption" in the sense of minerals and dissolved oxygen. undrinkable ! Drinking water must contain as a minimum from calcium and magnesium. in regulated quantities from which this device will have extracted 80 to 90% through its membrane.

Production of acidic water

According to the WHOa drinking water should be in the region of a Neutral pHor between 6.5 and 8.5, ideally 7.5. Nevertheless, your osmosis plant will produce osmosis water that will be acid, corrosiveThe pH of the water should be around 6, just like a carafe filter.

To find out more: Understanding the pH of tap water

Fertile ground for bacteria

A drinking water contains little or no bacteria. However, the 6-litre tank in your reverse osmosis unit, stripped of the chlorine that used to protect the water from contamination, will quickly become a nest for these little creatures (as with filtering carafes).

Finally, don't forget that osmosis water is stored at 20°C, or even 30°C in summer, which is a very high temperature. temperature highly conducive to bacterial growth.

And don't think that the osmosis membrane removes chlorine, because it can't handle it. In fact, it's the pre-filter that does this job, to avoid "burning out" the membrane too quickly.

So, of course, some more expensive models incorporate mineralisation cartridges (calcium and magnesium). Another excellent way of catching a few more bacteria. And.., why would you want to artificially put what naturally went in?

You can push the envelope even further (but not with plastic water bottles, okay? :)). This is done in the big machines of large French companies with the 'bio' label (yes, they sell you ultra-processed water on the spot, in plastic bottles, but you mustn't throw them in the wrong bin...), and restore the lost dissolved oxygen using a vortex.

But are you really sure you still want to drink this water? A far cry from natural waterthe exact opposite.

Read also: What are the environmental impacts of plastic water bottles and how can they be avoided?

In these very expensive machines and a top-of-the-range version, there's also a flash ofUV-C on the way out. This process does not kill bacteria, but only prevents them from reproducing in your stomach. Finally, there are many other pre- or post-filters that I won't go into here, as they are not to be found in a domestic machine.

Read also: What are the effects of UV-A, UV-B and UV-C on water, micro-organisms and health?

THE ENVIRONMENTAL IMPACT OF REVERSE OSMOSIS SYSTEMS

Let's take a closer look at theenvironmental impact : four filters and a non-recyclable membrane per year, and more than 60% of incoming water which is discharged into the environment as concentrated soup. You will of course pay for this wasted water in your bill.

Read also : 10 tips to make your everyday life more eco-responsible

Let's not talk about filters that will not be recycled or theincrease in your electricity bill linked to the use of the osmosis unit!

Do you still want a domestic osmosis unit?

Of course, for our part, we have given a great deal of thought to the the best way to improve the taste of tap water in a much simpler and more environmentally-friendly way!

You can test our tap water purifiers LAVIEand you'll see that we work miracles on water with a high mineral content. And you can even return the product if it doesn't suit you!

There is no installation, no filter to change, no bacterial pollution to worry about, no trace of chlorine or poor taste or bad smells. Just the pleasure of a clean water and an incomparable taste!

Read also: Tap water purifier: 7 questions to ask yourself when buying a purifier

FAQ on reverse osmosis systems

What is a water osmosis unit?

An advanced filter system that removes a wide range of contaminants, but can also remove essential minerals from water

Why drink osmosis water?

For its high purity, although it lacks minerals that can be beneficial to health.

Is it good to drink softened water?

Yes, for domestic use, but it may contain more sodium than untreated water.

Is it good to drink reverse osmosis water?

Yes, if you supplement the essential minerals with other sources.

Why install a reverse osmosis unit?

To reduce contaminants, taking into account the costs and environmental impact of the process.

What is the difference between an osmosis unit and a softener?

An osmosis plant removes a wide range of contaminants, while a softener reduces water hardness without removing chemical or biological contaminants.

What is the difference between a reverse osmosis unit and a UV-A purifier?

RO systems use a membrane to filter the water, removing many contaminants but also essential minerals. LaVie UV-A purifiers, on the other hand, disinfect water using UV-A light to eliminate bacteria and viruses without removing these minerals, offering a gentler method of purification that maintains the beneficial qualities of the water while ensuring its safety.

What is reverse osmosis?

Reverse osmosis is a water filtration process that uses a semi-permeable membrane to remove various contaminants, such as salts, bacteria and chemicals, from water. This method works by applying pressure to push water through the membrane, leaving impurities behind. The results of reverse osmosis include a significant reduction in total dissolved solids (TDS) and other harmful substances. However, this process consumes a lot of energy and discharges a large quantity of water as waste, and requires regular maintenance to prevent the membrane from clogging.

Where can I buy a reverse osmosis unit?

Osmosis units are available in :

DIY superstores (Leroy Merlin, Castorama).
Websites specialising in water treatment.
Online shops such as Amazon or ManoMano.

However, before you buy, it's essential to assess your needs carefully to avoid getting a model that isn't suited to your use.

Article written on 11/02/2023 by Pascal Nuti - CIO Solable - Passionate about energy, I'm constantly on the lookout for new targets for improvement, exploring cross-disciplinary paths using novel methods.