Pure Water Distillation Process

Now that you are through with your building and structuring and borehole, you have to start with the Distillation process. Distillation system is the most effective method of water purification for pure water production and can be used on all types of incoming water. Unlike other treatment methods such as carbon filters and reverse osmosis, distillation systems are effective on virtually all contaminants and are not dependent on water pressure, water temperature, pH, or chlorine and can even be used on water containing bacteria and parasites and still produce safe, 99.9% pure water.

Distilled water is water that has been heated to the boiling point so that impurities are separated from the water, which itself becomes vapor or steam. Steam is then condensed back into pure liquid form. The impurities remain as residue and are removed.

Pure Water Distillation Systems remove waterborne biological contaminants such as bacteria, viruses, organic and inorganic chemicals, heavy metals, volatile gases, cysts and other contaminants. Distilled water contains virtually no solids, minerals or trace elements. It is clean, natural and healthy. Steam distilled water is the standard by which all other waters are measured.

 

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Nevertheless, Reverse Osmosis is one of the most widely used and easier to install. Reverse Osmosis also produces water with highest level of purity and very perfect for your pure water production if you can afford it.

What is Reverse Osmosis?

Reverse Osmosis is a technology that is used to remove a large majority of contaminants from water by pushing the water under pressure through a semi-permeable membrane.

Whereas Osmosis occurs naturally without energy required, to reverse the process of osmosis you need to apply energy to the more saline solution. A reverse osmosis membrane is a semi-permeable membrane that allows the passage of water molecules but not the majority of dissolved salts, organics, bacteria and pyrogens. However, you need to 'push' the water through the reverse osmosis membrane by applying pressure that is greater than the naturally occurring osmotic pressure in order to desalinate (demineralize or deionize) water in the process, allowing pure water through while holding back a majority of contaminants.

Below is a diagram outlining the process of Reverse Osmosis. When pressure is applied to the concentrated solution, the water molecules are forced through the semi-permeable membrane and the contaminants are not allowed through.

Diagram source: Puretec Industrial Water

How does Reverse Osmosis work?

Reverse Osmosis works by using a high pressure pump to increase the pressure on the salt side of the RO and force the water across the semi-permeable RO membrane, leaving almost all (around 95% to 99%) of dissolved salts behind in the reject stream. The amount of pressure required depends on the salt concentration of the feed water. The more concentrated the feed water, the more pressure is required to overcome the osmotic pressure.

The desalinated water that is demineralized or deionized, is called permeate (or product) water. The water stream that carries the concentrated contaminants that did not pass through the RO membrane is called the reject (or concentrate) stream.

Diagram source: Puretec Industrial Water

As the feed water enters the RO membrane under pressure (enough pressure to overcome osmotic pressure) the water molecules pass through the semi-permeable membrane and the salts and other contaminants are not allowed to pass and are discharged through the reject stream (also known as the concentrate or brine stream), which goes to drain or can be fed back into the feed water supply in some circumstances to be recycled through the RO system to save water. The water that makes it through the RO membrane is called permeate or product water and usually has around 95% to 99% of the dissolved salts removed from it.

It is important to understand that an RO system employs cross filtration rather than standard filtration where the contaminants are collected within the filter media. With cross filtration, the solution passes through the filter, or crosses the filter, with two outlets: the filtered water goes one way and the contaminated water goes another way. To avoid build up of contaminants, cross flow filtration allows water to sweep away contaminant build up and also allow enough turbulence to keep the membrane surface clean.

What contaminants will Reverse Osmosis remove from water?

Reverse Osmosis is capable of removing up to 99%+ of the dissolved salts (ions), particles, colloids, organics, bacteria and pyrogens from the feed water (although an RO system should not be relied upon to remove 100% of bacteria and viruses). An RO membrane rejects contaminants based on their size and charge. Any contaminant that has a molecular weight greater than 200 is likely rejected by a properly running RO system (for comparison a water molecule has a MW of 18). Likewise, the greater the ionic charge of the contaminant, the more likely it will be unable to pass through the RO membrane. For example, a sodium ion has only one charge (monovalent) and is not rejected by the RO membrane as well as calcium for example, which has two charges. Likewise, this is why an RO system does not remove gases such as CO2 very well because they are not highly ionized (charged) while in solution and have a very low molecular weight. Because an RO system does not remove gases, the permeate water can have a slightly lower than normal pH level depending on CO2 levels in the feed water as the CO2 is converted to carbonic acid.

Reverse Osmosis is very effective in treating brackish, surface and ground water for both large and small flows applications. Some examples of industries that use RO water include pharmaceutical, boiler feed water, food and beverage, metal finishing and semiconductor manufacturing to name a few.

Note: Most pure water makers in Nigeria use just ultra violet bulb for purification which is not that effective but cheaper. And below is what ultra violet bulb treatment system look like.

Information source: Wealth Result, Puretec Industrial Water 

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