a friend of my family working in a water analysis lab in Brittany told me:
carafe filters remove certain particles but bring in others, it is better to consume tap water in a carafe in the fridge in the open air: chlorine is eliminated.
when it is eliminated it has already accomplished its action I think ...
good I did not notice at the time ...
I know that :
the sand filters the larger particles
(crushed) carbon filters chlorine and others
shells (crushed) retain heavy metals
quote:
"
Here is how to make a sand / carbon filter (like commercial filter cartridges):
> Take 2 large receptacles and fill 1 with sand: you must wash it at least 5 or 6 times to be sure of its cleanliness. To wash the sand, put it in a large basin, fill it with water and stir the sand in the water with your hands. Discard the water and start over with new water. Do this operation at least 5 times.
> Here is how to get activated charcoal from the trade: only use good charcoal that has been well burned and does not contain unburned pieces of wood, crush it well.
> Take the other container, drill it at the bottom with holes neither too big nor too small, the sand must not escape there, if necessary lay out a cloth.
> Pour in 5 cm of sand, then 8 cm of charcoal, then cover with sand.
This filter must be cleaned before its first use: the first filtration is carbon black.
Maintenance: The charcoal should be replaced approximately every two weeks. The polluting elements gradually contaminate the coal which, after a certain time can no longer retain them and lets them pass through. If the water you are using is very dirty, you will need to skim it regularly and perhaps change the top layer of sand every 2 days. If your filter becomes clogged (the water no longer flows below), you will need to change the two layers of sand as well as that of carbon.
> Sand is a filter element used to remove particles suspended in water. By doing this, it limits the possibility of viruses proliferation since they - unlike bacteria - are not autonomous organisms. The sand also removes iron, manganese and ammonium.
> clay as a mechanical filter is also very effective. If used raw, it can neutralize certain elements and facilitate flocculation (see definitions, below). Cooked, it retains particles on the surface and allows water to pass through. There are ceramic filters that can be arranged as a filter cartridge.
> Coal is indeed the most powerful natural poison pump (1cm3 represents 1km² of contact surface). It can absorb up to 178 times its volume in ammonia, it neutralizes anesthetic gases (masks in army NBC outfits contain it), chlorine, ozone, permanganate, agricultural chemicals, heavy metals , detergents, venoms, certain viruses and
recently, there have been effects on chemotherapy treatments. On the other hand, it is so adsorbent that it can inhibit oral contraceptives as well as certain drugs. In filters or for internal use, active carbon is used, which is vegetable carbon recalcined at the same temperatures in the presence of water vapor, air or oxidizing gas, which further increases its contact surface. But very good vegetable charcoal (hardwood, holm oak, coconut) is also very effective.
> Diatomites are siliceous rocks of organic origin (insect fossils) very effective as a filter, but must be changed periodically. Seashells recalcify rainwater and bind heavy metals.
Document: Blue Gold:
http://www.nrjrealiste.fr/eau/eau.pdf
