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Water Treatment Breakdown: What is the Motive for Aerating Water?

This article aims to describe various methods used by water treatment plants to make the water safe for drinking and usage. Water aeration is one of the mentioned processes, and it is described as the process of exposing water to air. Although this process may seem relatively simple, it plays some significant roles in water treatment. Let us briefly look at why water plants deem it necessary to aerate water.


Reasons for Aerating Water

 

1. Oxidize Dissolved Metals

2. Remove Volatile Organic Compounds

3. Adjust pH Levels

4. Increase Dissolved Oxygen

 

Let’s review these reasons in more detail.


Oxidize Dissolved Metals


There are various reasons why water is aerated, and one of them is to oxidize dissolved metals like iron, manganese, and hydrogen sulfide.

Here's a breakdown:

 

- Iron and manganese are two of the most prevalent metallic elements that are soluble in water in such places as lakes and rivers. Iron and manganese coagulate into solid lumps that can be filtered when in contact with air.


- Hydrogen sulfide is a highly toxic and flammable gas, which is non-cloudy and non-transparent; it is soluble in water and has an odor similar to the smell of rotten eggs. The bubbles float up through the water and the gas is precipitated as a solid sulfur particle that can be filtered.


If these metals are to go through oxidation and are not washed off, then the picture maybe as shown below. This means they can cause coloring of sinks and clothes, build up of scales in pipes, and even give the water an undesirable taste and smell.


Remove Volatile Organic Compounds


Another application is in the removal of volatile organic compounds (VOCs). The pollutants include volatile organic compounds such as solvents and fuel hydrocarbons from industrial effluent discharge and sources such as landfills.

 

There are several ways through which VOCs can be removed from water, for instance, when water is shaken, the volatiles go to the air and evaporate. The VOCs can then be treated by air filtration such as carbon adsorption. This has the benefit of eradicating the dangers usually related to the water.


Adjust pH Levels


Aerating water can also assist in changing the water's pH level, although this might take some time. The pH is a measure of how 'acid' or 'alkaline,' or 'basic' the water is. According to WHO, the appropriate pH of drinking water should range between 6. 5 to 8. 5.

 

When water is allowed to come into contact with the atmosphere, a specific chemical change will move the pH up or down to the required degree of acidity or alkalinity needed for distribution. This is especially useful to avoid pipe rusting and unpleasant tastes of minerals contained in the water.


Increase Dissolved Oxygen


Finally, water plants oxygenate water by agitating the water to introduce dissolved oxygen. This water is then released into bodies such as lakes, rivers, or the ocean where sufficient oxygen is required for marine life to support the aquatic habitats.

 

During aeration, air exposure to water directly impacts oxygen gas solubility on the water's surface. This level of dissolved oxygen is a little higher than the average river water, which allows fish, plants, and other life forms to survive.


Methods of Aerating Water


Now that we've examined the main motives, let's discuss the various methods that water plants use to aerate water:

- Core aerators distribute water through showers or steps where water is dispersed into the air to increase the surface contact area.

 

- Mechanical aerators add air into the water using paddles, blades, or even holes with small diameters.

 

- Tower aerators spray water upward in the distribution towers to ensure strong interaction with the air.

 

- Pressure aerators are those types of aerators that spray water under compressed air pressure.

 

The method you need depends on factors such as the water flow rate or the level of aeration required. To guarantee that sufficient exposure to air takes place, the appropriate control systems must be used.

 

Conclusion

 

We have reviewed the primary reasons and techniques for water aeration during the treatment procedure. Aeration may sound like a straightforward process of introducing air into the water.


Still, the primary functions include:


· The removal of hazardous elements

· Change in water chemistry

· Facilitating the existence of aquatic life

 

Therefore, whenever you take a glass of water from the tap with foam on top, do not forget that the water goes through rigorous air contact at the treatment plant.

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