Air compressors play an important role in the wastewater treatment industry and are a vital part of the wastewater treatment process. Compressed air runs through the three stages of the wastewater treatment process: separation, aeration, and oxidation. Almost every sewage treatment plant requires an air compressor, so efficient use of air compressors is essential for the operation of sewage treatment plants.

What do air compressors do in sewage treatment plant

In most sewage plants, wastewater treatment include three stages. Sewage enters the wastewater treatment plant from a variety of sources, including residential sources such as kitchens and bathrooms, commercial buildings, and rainwater from streets and buildings.

After the untreated sewage enters the plant in primary treatment (physical treatment), screens remove large objects such as debris and sticks. The sewage then enters a sedimentation tank, where solids and large particles sink to the bottom of the tank.

In this stage, air compressors or air blowers will help with flotation treatment and aeration. Air is introduced into the sewage to create bubbles. Impurities with a relative density close to that of water attach to the bubbles and rise to the surface of the water with the bubbles, and then are skimmed off by mechanical methods, thereby separating pollutants from the sewage.

(KSB Series Low Pressure Oil Free Screw Air Blower)

Secondary treatment is also called biological treatment. After sedimentation and separation, the sewage enters the microbial decomposition pool. The microorganisms in the pool absorb dissolved organic matter and convert it into inorganic substances such as carbon dioxide and water.

The oil-free air compressors will provide these microorganisms in the sewage with enough oxygen for biochemical synthesis and decomposition, oxidize and decompose organic pollutants and some inorganic poisons (such as fluoride and sulfide) dissolved in the sewage, and convert them into stable and harmless inorganic substances, thereby purifying the wastewater. After this treatment, more than 99% of organic impurities in the sewage will be removed.

Finally, tertiary treatment, also known as chemical treatment, is the last stage in modern urban sewage treatment systems and is a measure of advanced sewage treatment (also known as deep treatment).

Wastewater enters a chlorine contact tank for disinfection to eliminate harmful microorganisms such as bacteria, parasites, and viruses. After removing the chlorine, the treated water can be discharged directly into nearby natural waterways.

In summary, air compressor for sewage treatment plant is mainly used in the following aspects: instrument air, aeration, stirring, material conveying, sludge blowing, deep cleaning of filter tank, backwashing of filter tank/filter sand layer, sludge belt filter press dehydrator air source, combustion air supply for waste gas treatment, ozone machine, pneumatic valve, sludge dryer, poison gas replacement and other devices’ air source.

Types of air compressor for sewage treatment plant

Air blower: The air blowers commonly used in sewage treatment are Roots blower, screw blower and centrifugal blower. The characteristics of air blower are large air delivery and low air pressure, which are very suitable for air flotation and aeration operations in sewage treatment.

Screw air compressor: Screw air compressor has large gas flow and high pressure, which is very common in sewage treatment. Screw air compressor has the characteristics of high efficiency, low noise and good stability. It is widely used in instrument air, mixing, sludge cleaning, filter tank, ozone machine air supply and other applications.

Centrifugal air compressor: The centrifugal compressor has a large air delivery capacity and can work continuously for a long time. It is also very suitable for the aeration system in sewage treatment. The centrifugal air compressor has low noise and stable operation. In addition, the centrifugal air compressor also has the advantages of low energy consumption and long service life. It is the combustion air supply for waste gas treatment, toxic gas replacement, and the air source for sludge dryers.

(KOA Series Centrifugal Compressors)

Common pneumatic tools compressed air consumption list