Bladder and rainwater tank: compatible?

[kilou]

Hello,

new kid on the forum, I am about to install a rainwater recovery system from a buried pit (4m3) using a submerged pump and a pressure tank with butyl bladder (hydrophore group). Rainwater will be used for 2 toilets as well as for garden watering.

On the advice of several people, I have already invested in a large 200L tank in order to have a good useful capacity (around 40L) and therefore minimize pump starts, especially for WC use.

The problem is that I was able to read on several sites and forums Germans that it is strongly recommended not to use rubber (butyl) bladder tanks for rainwater. The reason is that the bacteria naturally present in rainwater, in the absence of air, start to eat away at the bladder and it quickly ends up piercing it ... This is not a problem of odor. linked to bacteria but the very reliability of the hydrophore group which would be called into question in rainwater use (which is not the case with drinking water of course).

I had never heard of rubber-eating bacteria but in any case for the Germans the only way to pump rainwater is with an automatic pump without a balloon. What do you think? Do you have rainwater systems that operate with a bladder tank without having to change the bladder every 2 years?

Thank you for your opinions!

PS:
A link for those who read German:
http://www.rewalux.com/ratgeber/rat.htm#Pumpen (go to the Pumpen section /
Hauswasserwerke)

[Forhorse]

Since you already have the ball, you might as well use it and see how long it will last ...

[kilou]

Hello,

I only have the ball at the moment. The rest of the installation will depend on the route to be taken because the pump will not be the same, the pipes will be different and there will be no pressure switch. In addition I really do not want to try to see because I want to achieve a "compliant" installation. So if the pumps with presscontrol are the right option I would rather sell the balloon new and in good condition rather than having to do it in 6 months or 1 year. Are there no recommendations on the type of pump to install specifically for rainwater in France? No matter how much I look, I can't find any info on these possible bacteria that feed on the bladders of the booster in the forums French. Maybe they only attack those who speak German

Is there anyone here who uses a bladder hydrophore group for rainwater?

[Rabbit]

I used one of 200l (not really given) for 4 years. no
worries. Then I moved. I could not put it back in place by
missing space. So I used low hydrophore groups of
range a + -100 €. The concern is that these groups do not last more than 3 years. It is the bladder that releases. I therefore stock pumps ... for 8 years.
If I can advise, I would say that it is necessary to install a hydrophore group
with an electronic hydrophore.
The reason is that it avoids running empty when the tank is empty.
As for the bladder, it prevents the pump from working at the
less leak of 2 drops of water.
If the hydrophore allows the pressure to be adjusted, 1.5 bars is more than enough at the highest point. In general these devices are set at 4 bars, being a turbine pump the 2 or 3 bar difference is a serious saving.
Regarding the pump, no need to invest in high-end.
Unless you have a lot of roof or live in England.
stock will not justify the price. The real economy is in the use of
washing machine soap which is divided by 2 and in the life expectancy of
washing machines which is at least multiplied by 2. I have a honey
who is 12 years old and does 2 washes a day on average. The only
repairs that I had to do are 1 join de hublo (tear due to forgotten objects in clothes),
2 evacuation pumps (wear of the shaft which pierces the pump) and
the 2 shock absorbers of the tank.
For water pipes, avoid metals and prefer soccarex. Rainwater is corrosive.
To limit this acidity, both for laundry and pipes, place
a limestone (size of a pave) in the tank and replace it
when it is digested. + - 5 to 10 years old it depends on the size
and the composition of the stone.
If the tank is made of concrete, coat the interior with a hydride mortar. The
problem is that concrete contains heavy metals. Avoid as much
to find them in his linen.
Also provide an aeration system (aquarium pump)
This will purify the water in the tank after introduction
organic matter (bird, leaves, moss but especially pollens) which
will rot later. When the stagnant water must be injected with air 10 min
every 2 to 3 hours.
Do not forget to filter the water. Debris of tiles or slates are fatal
to the washing machine or dishwasher valves. This causes leaks to these
valves, causing flooding. I took advantage of it and don't tell you
not wish. The magnetization valve is excessively expensive at miele.

[kilou]

Thank you for these details! So on average you last 3 years with 1 bladder. When you had to change the bladder, what was it like? Was there a bacterial film inside? Have you been able to observe if the cause of the bladder rupture was a tear or was it porous?

Regarding the pressure of the hydrophore group, as I want to use it both for WC and to feed a garden tap, I need more pressure. I am considering 3 bar at the garden tap so it is necessary at least for the group tripping pressure to be 4 bar, so the pump will have to provide at least 5 bar to put it under pressure.

[plasmanu]

A little idea.
Transform an old 200l hot water tank (2 ways) into a sanitary expansion tank (1 way).
By blocking the hot outlet at the top with a valve to allow the choice of indoor air level.
And use the cold outlet as an inlet / outlet.
I had tried at home by keeping it lying flat: this allowed the first filling to have 50% water and 50% air at atmospheric pressure and then block the hot water outlet.
Then the air is compressed and the booster was set to 3 bars.
All connected to the cold water part.
I used limestone spring water so not the faults of acid rain.
I also wanted to buy a new 200l sanitary bladder that fell legally from the truck for less than € 100, but Madame made a nervous poop: you're crazy, that's what to do again

[the middle]

For water pipes, avoid metals and prefer soccarex. Rainwater is corrosive.

I use a lot of rain water, and lately I have dismantled a 20 year old pipe, it was very corroded, I was surprised, because I believed that it was necessary to have air to have an oxidation.

[Rabbit]

Thanks for those details! So on average you last 3 years with 1 bladder. When you had to change the bladder, what was it like? Was there a bacterial film inside? Were you able to observe if the cause of the ruptured bladder was a tear or was it porous? "
Presence of a bacterial and porous film. With rainwater the
bacterial film is inevitable. You should not drink this water unless
to be highly immune.

Regarding the pressure of the hydrophore group, as I want to use it both for WC and to feed a garden tap.

For the WC 1 bar is sufficient. For the garden tap it is not the
pressure that matters but the flow. As long as the internal resistance of
conduit and the water column is under 1 bar you will have no worries.
But if I say 1.5 bars it is because the pressure switch does not allow to go
lower and because when the pump turns on the blow
belier releases the pressure switch.
By reducing the pressure, the pipes
will last longer.

Transform an old 200l hot water tank (2 ways) into a sanitary expansion tank (1 way).
By blocking the hot outlet at the top with a valve to allow the choice of indoor air level.
And use the cold outlet as an inlet / outlet.
I had tried at home by keeping it lying flat: this allowed the first filling to have 50% water and 50% air at atmospheric pressure and then block the hot water outlet.
Then the air is compressed and the booster was set to 3 bars.

It is the principle of the old hydrophore, before the rubber bladder.
Only precaution to take, regularly check the water level especially
when the pump starts too often. But this can be avoided by
leaving a slight air intake at the pump suction and installing
an automatic purge to the overflow of air from the tank. (towards the middle)
a little reading in this area: http://www.systemed.fr/forum-bricolage/ ... 28513.html

I was astonished, because I believed that it was necessary presence of air to have an oxidation.

Rainwater is acidic, which is why it must be neutralized with
a limestone. Just visit a used concrete tank
to realize that the water dissolves the cement from the concrete.

[Forhorse]

+1 with Plasmanu
In the past there was no bladder or membrane, it was a simple galvanized tank mounted vertically, the air was directly in contact with the water.
Just re-inflate the tank with air from time to time (exactly how those with a bladder by the way ...)
At my grandparents there was that (both) and that held for years despite the very acidic water of the Vosges mountains.

But frankly you take your head for nothing. A booster group costs a maximum of € 100 in trade and includes everything you need (pump, pressure switch and tank)
the performances are correct, the lifespan too. And if we want to improve the outlet pressure and / or the flow rate, just open them and modify them a little to block the venturi which is used for self-priming (but which suddenly drags down performance considerably)

Often it is the end of it due to improper handling (prolonged dry running) or because of frost but rarely by normal wear ...

[kilou]

A tank without membrane has a very low useful reserve compared to bladder tanks and it is often necessary to top up air because it dissolves in water. The bladder overcomes these problems.

Let's say that a rainwater recovery system to supply the toilets must be reliable! Why then are the Germans so fiercely opposed to bladder tanks to the point of recommending only automatic pumps?