Distilled water is generated as a consequence of boiling water, collecting the steam in a separate container, and then condensing it to remove contaminants and minerals. Reverse osmosis performs water filtration by passing it through multiple stages of filtration stripping off all the minerals. In the final filtration stage, it adds healthy minerals back into the water. Distillation, on the other hand, also purifies water but doesn't add healthy minerals to the water. Distilled water is not much benefit to drinking distilled water since it does not contain the same minerals as RO water. Both RO systems and distillers purify water by removing almost all contaminants. Both systems remove chlorine, chloramine, VOCs, heavy metals, and some bacteria and viruses. RO systems remove these contaminants by passing them through a series of filters, while distillers boil the water and cool down the resulting steam to a liquid state. Both RO systems and water distillers output water that is more contaminant free than most other filtration systems.

RO systems are not water softeners, but water softeners can be added as a form of pre-filtration. If your water contains high levels of water hardness, adding a water softener can preserve the life of your reverse osmosis system.

the carbon prefilter in an RO system removes chlorine before water reaches the reverse osmosis membrane. You may hear that reverse osmosis filters cannot remove chlorine, but these sources are referring to the RO membrane, not a full RO system.

A distiller does not work fast enough to be used for most cooking applications. RO systems filter enough water in a day to be used for washing dishes, cooking, and drinking.

Distilled water: Distilled water is water that has been boiled into vapor and condensed back into liquid in a separate container. Impurities in the original water that do not boil below or at the boiling point of water remain in the original container.

RO water: Reverse osmosis (RO) is a water purification process that uses a semi-permeable membrane to separate water molecules from other substances. RO applies pressure to overcome osmotic pressure that favors even distributions. RO can remove dissolved or suspended chemical species as well as biological substances (principally bacteria), and is used in industrial processes and the production of potable water.

Both RO water and distilled water is completely free of inorganic salt, organic salt, mineral and bacteria.

deer sir/Madam..

The two mentioned are technologies used for water desalination

RO means Reverse Osmosis depending on the Osmosis pressure..

While distillation depending on the temperature difference

Kishore kumar Sriramoju has described how the distilled water process and the Reverse Osmosis process works.

i would only make an important correction With respect to purity of product water made from these two processes.

First assume that the feed water contains dissolved salts ( TDS) of about 35000 ppm, a few ppm levels of organic matter that have boiling point in excess of 100 deg C and has about 5 ppm of suspended solids ( TSS)

Simple distillation at a moderate rate ( to avoid carry over of droplets) will yield product water of nearly zero ppm TDS and zero TSS and zero organics. Theoretically one can get almost 95% of feed water as product water of this quality. However in practical equipment, one does not aim for more than 50% recovery due to limitations of salting out scaling etc.

putting that same water through an RO process means that a suitable semi permeable membrane is chosen (usually polyamide based) and the water is retained on one side of the membrane and is subjected to high hydraulic pressure. Under such conditions a part of water molecules along with some dissolved solids permeates across the membrane. This water, called permeate typically will have 250 ppm TDS and near zero TSS and organics. Of course it is not possible to have very high percentage of product water. As the water molecules permeate forward, the remaining solution gets even more concentrated and soon the permeation stops. If we try to further increase the pressure of feed side, some more water ( again at 250 ppm) can be extracted but soon the solubility limits of feed water and mechanical strength limits of membrane are reached. In industry practice, starting with sea water that typically has 35000 ppm TDS, the recovery is usually about 45% only.

where use of water with very low TDS is needed, as for example in a high pressure boiler in a power plant, The RO water could then be deionized in a conventional ion exchange resin based water treatment plant

Hope you found the information relevant

@ Asha Dahiya: i presume you are a chemical engineering student and had answered accordingly. If however you were looking for some distilled water to top up your lead acid battery but did not readily have this, don’t use domestic RO Instead! The RO water, unlike distilled water has plenty of chloride ions in solution and this can seriously affect your battery!

RO water undergoes multiple filtration stages to remove contaminants and impurities, while distillated water is purified by boiling water and condensing steam. Moreover, RO water typically contains certain minerals, resulting in a slightly higher flavor than distilled water, which is considered neutral in taste.