Reverse Osmosis Membrane Elements
View Full Version : Backwashing a RO/DI Unit
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How To Sanitize A Reverse Osmosis (RO) or Reverse
Osmosis/Deionization (RO/DI) Water Filter
Chlorine is an excellent oxidative agent that can be used to sanitize and disinfect a RO or
RO/DI filter. If you believe you need to sanitize your filter unit follow the steps below:
1. Remove all filters including the RO membrane. If you have a “Taste & Odor”
polisher that needs to be removed too. IMPORTANT: You must remove the
RO membrane from the membrane housing before proceeding or you will
destroy the membrane.
2. Replace all EMPTY canisters except the 1st one.
3. Put 1/2 cup of household bleach in first filter housing and install it on the filter
unit.
4. Turn the source water on, slowly pinching the drain line to force water to exit the
membrane housing from both ports.
5. Wait to smell bleach from the drain and product side. If you have a drinking
water system you need to smell bleach from the faucet too. You can use a
chlorine test kit or your nose to test for the presence of chlorine. As long as there
is some bleach in all parts of the system you will be disinfecting it.
6. Once you have bleach to all ports, shut the water off and wait 20 minutes.
7. Check to make sure there is still bleach to all ports. If you smell the bleach then
you have successfully disinfected you filter system. If there is no bleach smell
left after 20 minutes it means there was still undesirable material in the filter,
which was not fully oxidized and you have not killed everything. In that case,
repeat the above steps until you can smell chlorine at the ports.
8. Now flush the system with fresh (no chlorine) water for 10 minutes. Make sure
water is flushed from both ports on the exit side of the membrane housing.
9. Test for bleach from all ports. If there is no bleach smell or chlorine left after
flushing you can reinstall your filters. If there is still bleach present, continue to
flush until all the bleach is all gone. IMPORTANT: You must be sure and
flush all bleach from the system before you replace the membrane in the
membrane housing or you will destroy it with the residual chlorine.
This is an excellent time to replace your filter cartridges to avoid any system
contamination. After reinstalling your cartridges, your filter will be as good as new.
Copied from the AQUAFX website.