Dorroco aerator is a type of Combined aerator.

Explanation:
Combined aerators are devices used in wastewater treatment plants to introduce air into the water for the purpose of oxidation and aeration. They are designed to maximize the contact between air and water, facilitating the transfer of oxygen to the water.

Dorroco aerator is a specific type of combined aerator that is commonly used in wastewater treatment plants. It is named after its inventor, Dr. Dorroco, and is known for its efficient and effective performance.

The Dorroco aerator combines both mechanical and hydraulic principles to achieve optimal aeration. It consists of a set of rotating impellers that create a vortex in the water. The impellers are driven by a motor, which provides the mechanical energy required for rotation.

The rotating impellers create a spiral flow pattern in the water, which enhances the contact between air and water. This spiral flow helps to break up air bubbles into smaller sizes, increasing the surface area available for oxygen transfer. The smaller bubbles also rise more slowly, allowing for longer contact time with the water.

The Dorroco aerator also incorporates a ridge and furrow design, which further enhances the aeration process. The ridge and furrow configuration creates turbulence in the water, promoting the mixing of air and water and facilitating the transfer of oxygen.

Overall, the Dorroco aerator is a highly efficient and effective device for aeration in wastewater treatment plants. It combines the advantages of both mechanical and hydraulic principles to maximize the transfer of oxygen to the water. Its spiral flow and ridge and furrow design contribute to the enhanced aeration performance, making it a popular choice in the industry.