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What is an Aeration Tank?

M. McGee
M. McGee

An aeration tank is a place where a liquid is held in order to increase the amount of air within it. The most common uses of aeration tanks are in wastewater recovery, as the high oxygen levels will increase the speed at which the water is cleaned. There are two main methods of aerating liquid: forcing air through the liquid or forcing liquid through the air. Both methods are common, but the aeration tanks are very different between the two types.

Wastewater reclamation using an aeration tank is very common. The water is mixed with biological agents and then aerated. The increased oxygen promotes the growth of the beneficial biological material. That material will consume unwanted waste products held in the water. Finally, the beneficial material will grow due to the increased oxygen and food, which makes it easier to filter from the clean water.

Aeration tanks work like fish tanks but on a larger scale.
Aeration tanks work like fish tanks but on a larger scale.

There are two main types of aeration tanks. When a tank has air forced through it, it is generally very shallow and wide. Tanks that put the water into the air are usually tall and take up significantly less ground space than the other tanks. In both cases, the tanks are typically open to the air, promoting additional natural aeration.

In an air-through-water aeration tank, the tanks have the aeration system built on the bottom. This usually consists of nozzles that force air through the wastewater. In many ways, this system works like the aeration system in a household fish tank, just on a larger scale. The nozzles cover the bottom of the tank, forcing air up continuously. In addition, these tanks usually have a system that moves the water around, making the mix more complete.

The most common uses of aeration tanks are in wastewater recovery.
The most common uses of aeration tanks are in wastewater recovery.

These tanks have an additional feature that isn’t present on other aeration tank styles. Since the gases are pumped into the water through the system, the operators can change the gas mixture however they want. This allows them to add additional oxygen for particularly dirty water or other gasses for other purposes.

A water-through-air aeration tank is a little more complicated. These tanks have a column-like pipe that comes up through the center of the tank. At the top of the column is a cone-shaped sprayer. The water from the tank is pumped up the column, where it hits the sprayer. The cone breaks the liquid into fine streams and mist. As this water recollects against the sides of the tank and in the air, it absorbs a lot of additional air before falling back into the tank.

Discussion Comments

anon295750

I am looking for an HD aerator pumps, one with 3.7 kw capacity the other with 5kw. What is the best brand.

browncoat

@pleonasm - Well, if you think an air into water tank smells, try a water into air. In that case they are deliberately forcing the water into a spray, so it acts just like a perfume spray.

The algae are actually the ones that make it stop smelling so bad, because they absorb most of the bits that smell. I've seen the cheaper version of this, an aeration septic system which lots of farmers use to process cattle manure in order to quickly put it back on their fields.

They usually just have a couple of holding tanks, one above the other and shift the waste water down in a stream so that it gets some air into it that way. The lower tank is usually quite shallow and is agitated as well.

It's actually a really good system, as the algae grow off the manure and then can be put onto the grass as an excellent liquid fertilizer, while the manure by itself would need a lot of time to rot down and become compost.

pleonasm

I've seen an air through water tank at a wastewater treatment plant and the open air design does nothing for the people who have to work there. Because, of course the water they are treating doesn't exactly small good and then you add a whole bunch of oxygen and swish the water around so that it gets into the air more.

We were all happy to be wearing masks, although they told us that they were actually pretty good in terms of the smell and that it didn't travel very far which is kind of important for the neighbors!

It's kind of ironic that growing algae in water will actually help to clean it, since the opposite is true in a fish tank. I guess it's easier to filter the algae that feed on the pollution than the pollution itself.

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    • Aeration tanks work like fish tanks but on a larger scale.
      By: Sergii Figurnyi
      Aeration tanks work like fish tanks but on a larger scale.
    • The most common uses of aeration tanks are in wastewater recovery.
      By: magralex
      The most common uses of aeration tanks are in wastewater recovery.
    • In standing water, the upper areas can have higher levels of oxygen than the bottom.
      By: Michal Adamczyk
      In standing water, the upper areas can have higher levels of oxygen than the bottom.
    • Many municipal water treatment plants process millions of gallons of wastewater each day, and then pipe it back to users or release it into the environment.
      By: chartcameraman
      Many municipal water treatment plants process millions of gallons of wastewater each day, and then pipe it back to users or release it into the environment.