Mechanical aeration design

Dykman, M. and B. J. Michel, Comparing Mechanical Aerator Designs, Chem. Engineering March 10, 1960, p. 117. 

Mechanical Aerators. Mechanical aerators are modular ia design and built usiag electric motors. This type of aerator is also known as a surface splasher because it pumps water vertically iato the air. During this process the water is broken up iato small droplets allowiag exchange of oxygen from the air to the water. One type of mechanical aerator is shown ia Figure 3e. 

The activated sludge process for domestic wastewater treatment was introduced to the world in 1914.1 Since then, many studies have been conducted to improve the oxygen transfer efficiency. Among the aeration devices introduced have been a porous diffuser, a filter type diffuser, a mechanical aeration device, an orifice type diffuser and a fine-pore air diffuser. The aeration market is in a substantial state of flux in the USA today. Emphasis on high efficiency has led many intensive research programmes to aim at the evaluation of the design, operation and control processes to improve overall system performance. 

In this chapter, the mechanics of hopper flow and standpipe flow along with their operational characteristics are described. Problems such as segregation, inconsistent flow rate, arching, and piping that disrupt and obstruct the flow of bulk solids in hoppers are discussed. Remedies with respect to the use of flow-promoting devices such as vibrators and aerating jets to reinitiate the flow are presented. The importance of the flowability of the solids to be handled in relation to the hopper design is emphasized. 

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