Everyone has been there. You’re taking a shower when you look down at the drain and wonder, “where does the water go?” All of the wastewater you produce goes down the drains and toilets in your home into the local sewer system or septic tank.
If you don’t have a septic tank, it then goes to a municipal water treatment plant. Here it is cleaned and processed for safe use in other areas. But how can we make wastewater safe to reuse?
One tool that is necessary for water treatment is the micro bubble diffuser. Please keep reading to learn about what it is and how it’s used to treat wastewater.
What Is Diffusion?
Diffusion is a process by which something concentrated in one area spreads out to fill a larger area. It happens with all sorts of things, from gases spreading out to fill a room to different liquids mixing together.
Diffusion occurs whenever there is a concentration gradient. This means some areas have a higher concentration of material compared to other areas. When this happens, the material naturally moves so that the concentration is uniform throughout.
Diffusion is necessary for all sorts of biological and chemical processes to take place. It is an important mechanism that pervades all of our lives, from inside our bodies to the Earth’s entire atmosphere.
What Is an Aerator?
One device that relies on the diffusion process to work is the micro bubble diffuser. This is a device that diffuses tiny bubbles of gas into a liquid or a different gas.
Typically, they diffuse bubbles of oxygen into liquids that need to be aerated, so they are similar in principle to wastewater aeration. Aerators work like a sieve or strainer to make air bubbles in a liquid.
In the case of water, they use compressed air to force water through a grating. This causes the water to split into many different streams that are separated by air bubbles.
These air bubbles quickly rise to the surface of the water because of their lower density. This makes it difficult for the bubbles to spread out evenly within the water.
Aerators tend to use lots of energy because they rely on compressed air. In addition, they also typically require stirring to fully diffuse the bubbles throughout the water.
What Is a Micro Bubble Diffuser?
Although similar to aerators, micro bubble diffusers have some essential differences. One key difference is the size of the air bubbles produced. As the name suggests, these devices produce tiny bubbles, down to fractions of a millimeter in size.
The advantage of having these very tiny bubbles is that they don’t rise to the surface of the water as quickly, giving them more time to interact with compounds in the water.
Because the air inside the bubbles is less dense than the surrounding water, they will always tend to rise due to the buoyant force. However, the surface tension of the bubbles will affect the buoyant force.
Higher surface tension will overcome the buoyant force and cause the bubbles to rise more slowly. Since the surface tension depends on the ratio of surface area to volume, smaller bubbles will have higher surface tension.
Although the exact mechanism that makes micro bubble diffusers work is proprietary, they utilize a concept called the hydrostatic paradox.
This says that the pressure at some point in a fluid is proportional to the distance to the surface of the fluid regardless of the surroundings.
What Is a Micro Bubble Diffuser Used For?
Micro bubble diffusers have found the most use in the realm of wastewater treatment. Whether your water goes to a septic tank or a municipal water treatment plant, aeration is an important part of the process.
One step in the treatment of wastewater is the use of bacteria to break down organic compounds within the water. These bacteria use oxygen in this process and release water and carbon dioxide.
Although they can find or make their own oxygen, this typically takes a long time and isn’t feasible for wastewater treatment. In addition, they could release hydrogen sulfide or organic acids in this slower process.
They need a catalyst to get them moving faster. This is where aeration comes in. Many treatment plants use conventional aerators to get more oxygen into the water for the bacteria to use, but these use lots of energy and are very inefficient.
Benefits of a Micro Bubble Diffuser
There are many benefits to using a micro bubble diffuser in a wastewater treatment setting. One of the most important is the smaller size of the air bubbles compared to conventional aeration techniques.
The smaller bubbles stay in the water longer, giving the bacteria more time to interact and clean the water. This greatly increases the oxygen efficiency in these systems.
Typical aeration systems tend to only use 5-10% of the oxygen they put into the water before it reaches the surface. In comparison, micro bubble systems can use more than 50% of the input oxygen.
Another huge benefit is the energy saved with micro bubble systems. Normally, aeration bubbles are pushed into the water with compressed air and have to be stirred to get the full diffusion effect.
Micro bubble diffusers use neither of these methods, so they save lots of energy.
A third benefit is the placement of the air bubbles within the water. Aeration systems typically only have one location within the water where bubbles are placed. Micro bubble systems can be placed throughout the water to get more even bubbles.
In addition, they can target certain areas with different oxygen concentrations.
Now that you know all about what a micro bubble diffuser is and how it works to clean wastewater, feel free to contact us for information about how we can help with your next project.
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