Reverse Osmosis, No Pressure

You’ve probably heard the term “reverse osmosis” come up regarding water filtration, but you might not be entirely sure what it means. How does it work? What has to be installed? How effective is it for your household? This technology is not as inscrutable as it may appear, though.

Osmosis is a natural process that occurs when two solutions with different solute concentrations are separated by a semipermeable membrane. The solvent is inclined to move through the membrane from low to high solute concentration, while said solutes are unable to pass, to reach equilibrium. This process can be reversed by applying high pressure to the high concentration region and pushing the solvent through to the low concentration region. The end result is leaving the solutes behind for a purer solution – in this case, pure water.

Reverse osmosis filters are more thorough in removing solutes compared to filters that are exclusively non-RO; primarily, this is due to differences in pore sizes. RO filtration systems may combine the semipermeable membrane with more traditional filters as well. This is especially vital for catching chemicals that might damage the membrane.

One consideration is that the necessary water pressure requires a lot of extra water for household systems. The purified water your RO system will provide is a fraction of how much water is going into the system – the rest is waste water carrying the filtered contaminants, and recovering this water without the solutes is inefficient for a residential system. In practice, the RO system will be installed somewhere specific in the household, such as under the kitchen sink, as it doesn’t need all of your house’s water passing through it. The filter also takes time to produce pure water, which will be stored in a tank for use.

If you want extra insurance on the purity of your drinking water, reverse osmosis is an option worth considering. Consult your local water filtration contractor to ask about RO products it offers.