Household RO systems typically filter water using the following steps:
1. Raw tap water first flows through a sediment filter to remove dirt, rust and other solid objects.
2. The water then flows into a carbon filter that takes out 98% of the chlorine and organic chemicals.
3. The next stage is the reverse osmosis membrane which separates 70-99% of the dissolved contaminants from the water molecules. These removed impurities are rinsed down the drain producing the final product, “pure water”.
4. This water is stored in a reservoir tank typically located underneath the kitchen sink and is accessed with a separate faucet.
5. When you open the valve the water is filtered one last time with a carbon “polishing filter” right before it reaches your glass.
Common Questions
Q.1: What is Reverse Osmosis (RO)
A.1: Reverse Osmosis (RO) is the finest filtration available. The RO process works by separating contaminants from water by forcing the water through a semi-permeable membrane. This membrane acts as a physical barrier to almost all molecules with a molecular weight greater than 200grams/mole.
For example, the membrane may allow passage of water molecules, but blocks molecules of dissolved salt. Unwanted molecules are blocked and discarded by the membrane while the ultra-pure water continues on for use/drinking
This process takes any unwanted molecules retained by the membrane and sweeps them away to your drain. This filtration prevents the membrane surface from clogging, thus permitting a long performance life.
Q.2: What are some of the advantages of Reverse Osmosis (RO)?
A.2: The advantages are:-
- Ultra fine filtration at the molecular level.
- Filters out 98% of all unwanted molecules.
- Membranes last typically a year
- Cross flow process prevents membrane from clogging.
- Easy to maintain, requires only routine maintenance which can be provided as part of our annual maintenance.
- Large storage tank for water-on-demand.
Q.3: What are some of the disadvantages of RO?
A.3: The disadvantages are:-
- Process is relatively slow, requires a storage tank.
Q.4: Why do I need a pre-filter system if the Reverse Osmosis (RO) Membrane takes out the contaminates anyway?
A.4: Reverse Osmosis (RO) membranes are designed to filter out contaminants at the molecular level. It is absolutely essential to remove water supply contaminants larger than 5 microns before passing it to the RO membrane to prevent fouling and clogging.
Q.5: Does Reverse Osmosis (RO) waste a lot of water?
A.5: It depends on what you mean by waste. A home RO unit uses water to clean itself and wash away impurities. It's like a lot of other water-using appliances. We use water to wash clothes, to wash dishes, to wash cars, to flush toilets. In terms of expense, it's like a couple or three extra toilet flushes a day.
Q.6: Does Reverse Osmosis (RO) remove chlorine?
A.6: A reverse osmosis membrane will remove chlorine but will degrade when in contact, therefore a Carbon Block pre-filter is used to remove the chlorine first thus protecting the RO membrane. Pre-filters will be changed regularly to prevent membrane fouling, as part of a regular maintenance.
Q.7: How often does the Reverse Osmosis (RO) membrane need to be replaced?
A.7: With proper maintenance of your sediment and activated carbon pre-filters, your reverse osmosis membrane should last a least a year and recommended replacing yearly due to bacteria/sanitary
Q.8: What is meant by Total Dissolved Solids TDS?
A.8: In the natural cycle of water, water that began its life as rain and eventually found its way to your tap has come in contact with many sources of potential contaminant. The various minerals and salts that have been dissolved by the water during this cycle are called Total Dissolved Solids (TDS).
Q.9: Is it necessary to change the filters on my system every 12 months?
A.9: Yes and this can be scheduled and carried out by our technicians as part of our annual maintenance or filters are always available at our store . Our systems have been designed to operate best to give high quality purified water with normal routine maintenance. By changing the filters on a regular basis, you will eliminate dirt and chemicals in the water that will plug the membrane. After six months of use, the carbon filters can have bacteria growing within the filter media. Your local water conditions may necessitate more frequent filter changes.
Q.10: Can I remove the nitrates from our water when using a Reverse Osmosis (RO) unit?
A.10: Nitrate removal when using reverse osmosis membranes is about 90-95%. So if you currently have 10 ppm of nitrate, then your levels after treatment should be around 0.5 - 1ppm.
Q.11: Are your membranes good quality?
A.11: In short the answer is yes they are top quality.
Our membranes are manufactured in the USA, They have an excellent rejection rate of between 92 – 98%
Q.12: Can you hook the Reverse Osmosis (RO) unit to my fridge/icemaker etc?
A.12: Yes, and to your coffee-maker, ice-maker, steamer and to any other appliance requiring potable water.
Water & Air Works
3110 NE Minnehaha St., Unit B
Vancouver, WA 98663
Phone: 360.696.9287 Fax: 360.695.1226