I wrote more than a year ago that I tested the water in the well and found a lot of manganese in the water and that I needed to install a reverse osmosis plant to solve the manganese problem.
I installed it. It’s been over a year, and I recently changed consumables (filters), so it’s an excellent opportunity to write about this topic.
Technical stuff
There are currently two main types of reverse osmosis stations for domestic consumers: with and without a booster pump. I chose the booster pump option because I live at home, and the water pressure in the system is too low for reverse osmosis to work otherwise.
For those with high water pressure, i.e., 7-8 bar, you can also go for the version without a pressure pump. This generally means the lower floors of the block.
The reverse osmosis station I chose was made by Eco Krausen, and I bought it from eMAG. I didn’t know much about reverse osmosis when I purchased it, and it’s definitely not the best model available on the market.
It is a computer-equipped station that should automate many of the functions of the reverse osmosis station. It should flush the reverse osmosis membrane at regular intervals automatically. It also shows how much of the filters’ life is left. What’s bad about this computer is that all the buttons are marked in Chinese. It didn’t come with a user manual and has extremely annoying behavior when the power goes down: when the power comes back on, it starts with some extremely annoying and loud beeps. This leads me to not recommend it. It’s annoying to have it beep with every hiccup in the power supply voltage.
Most reverse osmosis systems for domestic users have six stages of water filtration. Three filters are ahead of the booster pump and reverse osmosis membrane: a polypropylene filter to retain large impurities and two increasingly fine-grained activated carbon filters to retain as much of the water’s chemicals, chlorine, and other impurities as possible. Next, the water passes through the reverse osmosis membrane. Finally, an activated carbon filter improves the water’s taste, and a remineralization cartridge adds minerals back into the purified water. The system I bought also has an additional UV lamp to remove any bacteria that has managed to pass through the system so far.
This mineral thing goes like this: the semi-permeable reverse osmosis membrane is 0.0001 microns. Water molecules pass through it, but other very small molecules (impurities) can also pass through. About 97% of impurities can be removed without problems by passing water through the reverse osmosis membrane.
In particular, nitrites will pass through reverse osmosis without problems, and if your water has a lot of nitrites, reverse osmosis will not help. Nitrates are retained at about 80%.
On the other hand, the reverse osmosis process will also remove useful salts and minerals from the water. That’s why the remineralization of water is important.
Anything that does not pass the reverse osmosis membrane must be discarded. This can be done automatically, as is the case with my computer station, or it can be done manually by opening a tap. Whichever option is chosen, the result is the removal of contaminated water to the sewer. If this operation is delayed too long or the reverse osmosis membrane is not flushed, it will eventually clog, drastically reducing its life.
Under normal maintenance, the first three filters and the two post filters are changed every six months. The reverse osmosis membrane is changed every 1-2 years depending on the degree of use. I do change mine every year, the manganese is a real pain in the well-you-know.
When I did my first filter change, I chose a set of supplies from Filtro.ro originally intended for the Balance station. These filters are equipped with quick connectors directly on the filter. As such it was necessary to make some small modifications to my reverse osmosis station to be able to use these filters in the future.
I had to replace some hoses that were too short for the new quick connectors, and after the post-filtration cartridge with granular coconut shell activated carbon, I had to install a T-type quick connector. All these modifications cost under 20 RON.
These changes are made only once. In the future, I will be able to use the Filtro consumable sets without any further intervention.
Installation
The space occupied is quite large because, in addition to the reverse osmosis station, there is also the 12l expansion tank. Pretty much all the space under the kitchen sink. I preferred to use the services of a plumber because I already had the dishwasher connections under the sink and it was quite crowded in there.
The water supply part comprises four hoses. A cold water supply hose. Another for the discharge of water from the reverse osmosis membrane washing. The third hose goes to the expansion tank. Finally, the fourth hose goes to the water tap. To install the water tap it is necessary to drill a 10mm diameter hole in the sink.
It is also possible to replace the existing tap with a three-way one, thus combining normal and purified water operation. This eliminates the need to drill holes in the sink.
Electricity is also needed for both the osmosis station and the UV lamp. The latter is permanently operational.
Costs. Savings made.
In one year of use I have changed two sets of filters. Cost about 500RON.
We use a minimum of 10 liters of water a day, both for drinking and cooking. So at least 3650 litres of water per year. This results in a cost of 0.14 RON/liter. Let’s say 0.2RON/liter because I didn’t measure electricity consumption. All prices are calculated at 2021 level.
If we used tap water for cooking, as full of manganese as it is, and drank plain water from 5l jugs then we would need 360 jugs of water to cover our current consumption. The cheapest bottled water I have found so far is Codrii Vlăsiei at 4.04 RON/can (0.81 RON/liter). Taking this price into account we would have paid about 1400 RON per year for water and thrown away a lot of PET bottles.
In reality, we are not really saving that much because we still drink PET-bottled water from different producers, trying to get a balanced mineral intake from the drinking water. Add to that sparkling water, at least until I get SodaStream. I think we save about 800 RON annually. So, I can say that in the first year, we completely covered the initial cost of the reverse osmosis station, which is not bad at all.
In addition, we have reduced our bottled water consumption by more than 80%. Hundreds of PETs that never made it to recycling.
These days, I also measured electricity consumption. In standby, with the pump switched off, the consumption is 8W, mainly due to the UV lamp. With the pump on it consumes 31W, and when washing the osmosis membrane, with the pump and solenoid valve on, the consumption rises to 40W. On average about 1 kWh per day.
One last update
Today, 22 November 2023, the reverse osmosis station failed completely. We experienced some power outages, with the power coming back on for 1-2 seconds, then down again. The station’s computer is totally messed up. It beeps nonstop and does nothing else. It stopped reading the flow sensors; it stopped starting the pump.
In the meantime, we got an infrastructure upgrade, and I’ve managed to hook up to the city’s water supply. I’ve decided not to bother with the repair. Overall, it was an OK investment; it did well when I needed to.
