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Treatment of brackish water into domestic water

What is the best way to treat saline water into domestic water? Treating Saline water simple, highly effective by RO water purification system.

The problem of saline water causes many difficulties for daily life, production… Therefore, many measures have been applied to treat saline water into domestic water. So, what is the best way to handle it, which is both simple and cost-effective?

1. Learn the difference between saline (brackish) water and seawater

Currently, the Western (Mekong Delta) provinces and some coastal areas are very salty due to the encroachment of sea water into the mainland, climate change and a number of other causes, including anthropogenic.

Saline water is fresh water that is encroached on by salt water or sea water, with a lot of salt but mainly NaCl. Fresh water is contaminated with salt through 2 ways:

– Groundwater circuit: The prolonged dry season lowers the groundwater level, creating conditions for sea water to infiltrate.

– Groundwater level decreases while sea level rises: The water level of rivers and streams has been lowered along with sea level rise.

Although the salinity in brackish water is not high, it also causes big problem in terms of water shortage for daily life, agriculture, fruit trees, livestock, freshwater aquatic products, etc. Therefore, treatment of brackick water into domestic water urgently need today.


Salty contaminated water and soil making many difficulties for daily life and cultivation

Not only lack of fresh water, excess saline water, but when the soil is salty, it takes a lot of water or after a period of rain soaks enough to wash the salt out of the soil.

Treating brackish water is much more difficult than treating salt water (sea water) because:

Except for domestic water supplied by water supply companies or often using rain water like households, domestic water is only available from treating well water or treating surface water of rivers and streams.


Main sources of domestic water supply

– When the water source is salty, it is necessary to add the further treatment of saline water to domestic water, change the existing treatment systems because salt cannot be treated.


Step “Brackish water treatment” must be added to existing treatment system

– Meanwhile, the year-round sea water treatment system can be easily solved or only partially renovated to treat well water or and river water into domestic water. However, this happens very rarely because the seawater filtration system is a source of always salty water.

– On the contrary, it is very difficult to treat salinity from the existing system well water or river water because the cost of removing salt is very high.

2. How to treat saline water into domestic water

2.1 Steam Distillation (For reference only, not practical application)

Using energy to evaporate or boil water such as solar energy, electricity, firewood, coal, etc. After that, it will be cooled down to obtain a quantity of salt-free domestic water. However, this method of treating saline water into domestic water is for reference only and is not effective when applied in practice, because:

– It takes a lot of energy and costs to get the desired amount of water.

– It takes a lot of time.

– Distilled water still contains other impurities whose boiling point is lower than water at 100, mainly organic compounds containing dissolved gases. Because it no longer contains Ca, Mg and some other minerals, distilled water has a light taste, which is both difficult to drink and does not guarantee the amount of minerals for health.

– Only suitable for the laboratory

2.2 Use Ion exchange resin to remove salt (Only suitable for company size)

Using cationic and anionic resin to remove salts and other ions from the water, will have no more salt. However, this method of treating saline water into domestic water is only applicable to large systems of the plant because the resins have to be regenerated very complicatedly and need to be sterilized and replenished with minerals.

2.3 Transporting fresh water to salt-affected places

‘Transportation is also a fast and flexible way to have fresh water for domestic and production use. Transport by tank truck will go deeper into each area, alley but limited in quantity, if far, the cost may increase. Shipping by barge will be large quantity but depends on the river water level up and down during the day and continue to divide for tank truck as above

2.4 Treatment of brackish water with RO membrane system

Using reverse osmosis (RO) membrane is now considered the most popular, effective and simple to treat brackish water into domestic water.

– Any capacity can be met, from individual households to clusters of families or at the scale of production companies. Equipment also depends on the budget so the price will vary.

– If want water to use right away just turn on to operate RO machine. Installing a UV light after the RO membrane will have safety to directly drink or bottled for mobile use


Using RO membrane to treat salty water and adding minerals back become domestic water

Brackish water, after being filtered through the RO membrane, removes almost all of the ions in the water, leaving no minerals. Therefore, it is possible to add minerals by adding 5 – 20% with water filtered 5 microns before the RO membrane depending on the salinity from water source. Maybe this amount of mineral is not enough according to existing technical regulations on domestic water or drinking water but this dilution will be much better than non-mineral water.

RO purifier with 1m3/hour is enough for family, livestock and watering fruit trees in garden

Note that the rejected water of this RO machine must not be discharged into the soil because if it is soaked for a long time, it will make the polution to soil. Discharged water has salinity 3-4 times higher than untreated salinity, so it must be diluted by slowly drainage to river or canal when at high and low tide.


Treatment of saline water by RO system for large capacity plant

2.5 Treating brackish water into domestic water for people in need

Use rain water, store fresh water

The unit price for 1m3 of RO water is not high, but it is difficult to have an RO purifier for the whole family (not to mention for livestock and plants). The best way is to save water and retain rainwater in times of drought and salinity.

Traditional rainwater storage is the use of ceramic containers, but today can buy containers made of flexible plastic that can be folded when not needed. It should be noted that rainwater must still be boiled before use because it can be contaminated with bacteria and should not be used at the beginning of the rainy season because it contains high acidity or from dirty roofs.


Simple rainwater storage and filter, remove dirt from the bottom

Stocking up on fresh water in containers is as important as life’s necessities. However, it should be noted that this stored fresh water needs to be boiled to avoid bacteria before drinking


Traditional storage tank, concrete tank for rainwater, freshwater


Portable big container,  towed away when not in use

2.6 Support from local authorities and benefactors

– In the past time, it is very valuable to install a saltwater treatment system to have fresh water for people in difficulty, helping them to have enough domestic and drinking water, without so worrying about lack of drinking salty or polluted water but there are many areas still need to get the help.

However, in order to have fresh water for cattle, crops and livestock, this must be a big project of the State on a provincial, regional or national scale or of a large company because it takes up a lot of capital to deal with salty


Youth union supports in clean water treatment for poor people

Thus, there are many different ways to have fresh water in saltwater areas for daily life and production needs. In particular, treatment with RO water system is simple and popular at present

If you need more information or need to install a water treatment system to remove salt, alum contaminated, please contact us directly UCE Co., Ltd for quick support.