How to Reduce TDS of Water?

How to Reduce TDS of Water

What are Total Dissolved Solids?

TDS or Total Dissolved Solids is a terminology that many are seemingly unaware of. We know this for a fact that the drinking water we consume today is ridden with harmful chemicals coming from treatment facilities across the country.

What happens is we successfully eradicate any and all kinds of useful minerals present in the water, which can be really bad in the long run. The main factor which is the root of all this is the Total Dissolved Solids or TDS that remain left out in the water post a simple filtration process.

If we have to go in terms of technicalities, the impurities which are greater than 2 microns would come under this category. Generally, a filtration process removes the contaminants that are about 0.45 microns coming from multiple sources.

The remainder of these contaminants is left out in the water harming its aesthetics characteristics completely.

If there are a copious amount of TDS present in the drinking water, it might prove fatal giving rise to multiple health problems. Therefore, it is important that the TDS amounts be taken care of especially when it comes to drinking water bodies.


Acceptable TDS levels in Drinking Water

We would be giving you a tabulated format which sheds some light on the acceptable TDS Levels in the drinking water. Let us take a look at the optimum amount that can be ingested by the human body. You can measure the TDS level by using the best TDS meters.

TDS Levels (in Milligrams)Comments
Lower than 50Not a good choice to consume since the water will have lower mineral content.
50-150This is the optimum level of consumption, and it can be termed as a fairly acceptable level.
150-250This is a good enough level, and it can be used for the treatment of cardiovascular diseases.
250-350Another good enough level which can be used for the treatment of cardiovascular diseases.
350-500Passably OK Level.
500-900Not admissible at all.
900-1200Another one that cannot be allowed for consumption. Levels over 900 would be deemed unfit for human consumption.
1200-2000Unacceptable for consumption.
Above 2000Fatal.


Steps to reduce the TDS in water

We would now be looking at some of the important measures that would prove beneficial for industries and other facilities for reducing the TDS amounts in the water. Specifically, we would be talking about three processes that matter and will help out immensely.

Let us take a look at them for a better understanding,


1) Reverse Osmosis (R.O.)

What is Osmosis?

To understand the workings of Reverse Osmosis, you need to understand what is Osmosis. Osmosis is a naturally occurring marvel wherein a fragile saline solution would be migrating to a stronger counterpart.

The best example of this would be the fact when the roots of the plants absorb water from the soil where it is based.

  • Suppose we take a container brimming with water that has lesser salt concentration, and another one that has a supposedly greater salt concentration.
  • Both of these containers are essentially separated by a semi-permeable sheet in literal terms. Over time, the water with less concentration of salt would start mixing towards the one with the higher concentration of salt.
  • It’s a perfectly stable and natural process that takes place.


What is Reverse Osmosis?

Reverse Osmosis, on the other hand, is the complete opposite as you can make out but in a slightly different way. The reverse process can be defined as the osmosis process carried out with the application of external energy.

  • There are natural components involved in Osmosis which is not the case in Reverse Osmosis.
  • If we take the same experimental setup as before, the energy would be applied to the water with concentrated levels of salt.
  • Another factor which should be taken into account is that the membrane present in between these two containers would allow the water molecules to pass through.
  • This would ensure that the dissolved salts and other contaminants would be left behind.
  • The reverse osmosis would require the user to put in enough energy so that you can push the water out of the other side.
  • In comparison, the pressure applied during the Reverse Osmosis process needs to be higher than the Osmosis eliminating any naturally occurring osmotic pressure thereby removing the salt contents.


Impact of R.O. on TDS Levels

  • The process also makes sure that it allows in the pure water whilst keeping at bay the majority of contaminants and other pollutants.
  • Reverse Osmosis would keep out the TDS pollutants including colloids, organics, bacteria, and other pyrogens out from the fresh water.
  • It is one of the first and foremost steps in clearing out these harmful levels.


2) Distillation

What is Distillation?

Simply speaking, distillation is a simplified process of segregating multiple compounds with respect to contrasting conditions that would change the appearance or juncture of the said mixture.

Since the baseline that we are discussing is on water, a change in phase for water would be the formation of water vapor.

  • The vapor or gas collected is again put into the condensation process and turned back into the liquid form, which is then collected.
  • The process is repeated many times and over and over again to maintain continuous purity factor. This is what the distillation process is all about.
  • This process is mainly carried out at professional setups called distilleries where they carry it out with respect to the nature of the compound.


Types of Distillation

a) Simple Distillation

  • This process is used when the boiling temperatures of two liquid products would be completely contrasting to each other.
  • Simple distillation can be used to split up the liquid materials from the solids or in chemical terms, non-volatile components.
  • The said mixture would then be heated at an optimum temperature to change the liquid material into its vapor form.
  • The vapor would then be siphoned off into a condenser station. Post which it is cooled off, and then collected in a separate chamber.

b) Steam Distillation

  • This process is specially designed for isolating the temperature-sensitive or thermal materials from the volatile mixture.
  • Another material which is added to the mix would be the presence of steam.
  • This takes care of the fact that the liquids would be evaporated immediately, which is then collected separately.

c) Vacuum Distillation

  • This process is designed for components that have elevated boiling points.
  • If this is being done practically in a laboratory, then decreasing the pressure in the equipment would lower the boiling point levels.
  • Vacuum Distillation becomes extremely important when the boiling point outstrips that of the temperature required for the putrefaction of that compound.

Impact of Distillation on TDS Levels

Distillation is very vital in lowering the levels of TDS considerably since it ensures that the vaporized output in the chamber is the purest.


3. Deionisation

What is Deionisation?

Deionisation is a rather advanced process to weed out the TDS contaminants from inside the water.

It is a process that has been well accepted by many industry experts and also recommended by many.

  • The main components that are utilized during this process would be the ion exchange resins.
  • These resins help out in taking full control of the electrical current based ions in the water. This removes the traces of TDS particles out of the water.
  • The process also takes out the charged-up molecules or atoms from the liquids, and it takes place with the presence of two resins.
  • Water is essentially passed in through them thereby removing the positive and the negative ions completely.


What happens exactly?

  • The positive ions are called the cations and the negative ions are called the anions. These two play an important part in the process and are directly responsible for the Deionisation process.
  • The anions are basically made up from the ammonium groups that are already charged up with hydroxide ions, and they are positive. These resins basically attract the negatively charged ions which include chloride, sulfate, fluoride, thereby extracting equal amounts of hydroxide.
  • On the other side, the negatively charged sulfur groups are charged with hydrogen ions which are seemingly positive.
  • This process happens on the cations and the respective resins would be attracting positively charged ions like calcium, magnesium, sodium releasing the optimum amounts of hydrogen.
  • Both the hydrogen and the hydroxide combine together giving us the perfect compound called water.


Impact of Deionization on TDS Levels

  • The Deionization process is very effective owing to the fact that it is completely cheap, and it’s an easy method thereby producing effectual results.
  • It also helps in the removal of the inorganic and organic salts owing to a process called ion exchange.
  • It is immensely helpful in controlling the harshest effects of TDS on drinking water, and it is productive and a proven method.



TDS levels above a certain point of time can be fatal for ingestion as we have seen in the reports above. It is, therefore, necessary at some point of time to tap into these three major processes that would create an impact and lessen up the count.

Moreover, as citizens, you should take care of this, and be mindful of this. You can have measures put in place so that the situation does not escalate after a certain point.

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