March 1st, 2005 at 11:21 am
The water in the water cooler at work is from Nestle. It says that itâ€™s been filtered through a â€œReverse Osmosisâ€ process. What does that mean, to me the consumer, and is this better than other filter methods? Should I prefer it over Brita filtered water?
I can state this definitively: Reverse Osmosis is better than most other filtration methods.
In this answer, I will break down the most common water filtration methods, describing each, in order to prove that Reverse Osmosis filtration is better than the rest. The most common filtration methods are:
– Ion Exchange
– Carbon Adsorption
– Reverse Osmosis
Distillation is when you take your tainted water and evaporate it, directing the vapor towards some sort of condenser, where the water collects and drips into your drinking bucket (I assume you drink out of a bucket). This is okay, if you’ve got time to wait for your water to evaporate, condense, and drip, and you happen to have a really powerful source of energy to point at the water in order to make it evaporate or boil (like a death ray). It’s also okay if you want to drink bug killer, since that stays with the water when it evaporates.
This is when you have a bucket of salt beads to push your water through, and your water has a lot of metal in it (like iron and manganese). What happens is that the dissolved metal ions in the water stick to the beads of salt and (somewhat like bartering) exchange sodium ions for your water’s more valuable iron or manganese. The beads will then take the metals and trade it in for a brand new moped, while you are left with “soft” water. The problem with this method is that it doesn’t remove chunks of badness from your water (this is called “particulates” by the faint of heart). Also, bacteria likes to live on the beads, which makes your water nasty.
This is what a Brita does. Basically, your water flows through a block of “activated” carbon. “Activated” means that the carbon has been charged up by your death ray and that you have inserted the “Key of Horus” into it. It can also mean that the block of carbon was heat-treated in such a way that it has lots of tiny holes. These holes function as “jail cells” from which bad things cannot escape. These jail cells trap dissolved organics and chlorine effectively. This makes your water taste good, and it provides some measure of good feeling since you know that most of the bad organic stuff is now in jail. However, like any jail, the cells eventually fill up and you have to change your filter. This method also does not guarantee the removal of lead or coliforms from your water.
Filtration is when you force your water through something with very small holes (like one of those strainers that I sometimes use to create pulp-free lemonade). This is good for removing anything in suspension, but bad for removing anything that has been dissolved. Enough said.
Like filtration, but its taking the volume up to 11. You actually filter out molecules with one of these. Still not good for getting rid of stuff that’s dissolved in the water.
This is the king of water purification methods. As you are most likely aware, regular osmosis occurs when two solutions of different concentrations are place next to each other, with a semi-permeable membrane between them. Water will leak through the membrane until the concentrations are equalized (because water is totally controlled by peer pressure and wants to be just like everyone else). Reverse osmosis occurs when you apply hydraulic pressure to the solution, forcing the pure water to go through the membrane the other way, into your pure water collection place. Practically nothing gets through the Reverse Osmosis membrane. But, because the membrane is so fine, it takes a long time for the pure water to come out. Luckily, if you are drinking water that has already been purified via Reverse Osmosis, you don’t have to wait for anything – it’s already there. Reverse osmosis is especially good for removing any dissolved radioactives, like plutonium. So you are less likely to mutate.