Wednesday, December 06, 2006

RO Water

Here is an extract from wilipedia on RO (Reverse Osmosis).

Reverse osmosis (RO) is the process of pushing a solution through a filter that traps the solute on one side and allows the pure solvent to be obtained from the other side. More formally, it is the process of forcing a solvent from a region of high solute concentration through a membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure. This is the reverse of the normal osmosis process, which is the natural movement of solvent from an area of low solute concentration, through a membrane, to an area of high solute concentration when no external pressure is applied. The membrane here is semi permeable, meaning it allows the passage of solvent but not of solute.
The membranes used for reverse osmosis have no pores; rather, the separation takes place in a dense polymer layer of only microscopic thickness. In most cases the membrane is designed to allow only water to pass through. The water goes into solution in the polymer of which the membrane is manufactured, and crosses it by diffusion. This process requires that a high pressure be exerted on the high concentration side of the membrane, usually 2 - 14 bar (30 - 200 pounds per square inch) for fresh and brackish water, and 40 - 70 bar [(600 - 1000 psig)] for seawater, which has around 24 Bar (350 psi) natural osmotic pressure which must be overcome.
This process is best known for its use in desalination (removing the salt from sea water to get fresh water) and has been used in this way since the early 1970s. Its first demonstration was done by Sidney Loeb and Srinivasa Sourirajan from UCLA in the California town of Coalinga.

Confuse still !!??

Now let’s see if I can make it easier.

It is like normal filtering of water that we are so used to. The difference here is that it uses pressure to push water through a membrane (filter) so that particle or other molecules beside hydrogen and oxygen (h2O) the atoms that make-up water only goes through. That’s it.

The main component of a RO machine is a pump that provides the pressure and membrane to reverse filter the source water. There are so many commercial type and even mini house hold RO machine.

From my experience when I was working on a Resort in Sipadan we have a commercial type RO machine that can produce 1,200 gallon or about 4,542 liters per day or 24 hours operation. This is making fresh water from seawater. And we had a same capacity unit on a yacht. There are even much bigger commercials capacity RO water maker in the market.

As mention that all you need to make RO water is to force water using pressure through the membrane to produce RO water. Before this if you want to per long your expensive membrane you will need to pre-filter the source water with additional filters of minimun 5 micron. But if you can afford better per filter that is even better.

As mention I had a RO machine on a yacht, sadly the water source was very very bad with lots of sediment that we had to clean our pre-filters once every 2 days. It was different in Sipadan, the water source were from a well dug on the Island. The source water is pre-filtered naturally before it was feed to the membrane.

Here we are looking at household RO system. The water of course is now fresh water that came from the tap. Is the tap water clean? NO. That is why it is recommended that it be at least boiled. So here we feed tap water to our pre-filter and then to the RO machine.

But is RO water ‘really’ good for us? Yes, as it is ‘Pure Water’ with no other element in it. Hey don’t we need all the element (mineral) for a health body or the balance our body and blood ph. YES, but RO guru says that we can get all this mineral from other food source like vegetable. (Another good topic to talk about what we consume).

Some RO manufacturers even claim that their water is hospital standard. Yes but we are not in the hospital yeah? No argument that RO water is good. Still there are many other source making clean water.

Personally to produce RO water is still expensive for home use and not many households can afford a RO machine.



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