Chapter No. 9 : Aeration and mixing
Aeration is an essential process in most wastewater treatment systems, representing the highest energy cost. Through aeration, oxygen is transferred into the liquid media and utilized by the microorganisms for the removal of organic matter and nutrients. Oxygen can be transferred by shearing the liquid surface with a mixer or turbine, releasing air through macroscopic orifices or porous materials, or through direct contact of air and a large water surface.
This course consists of 3 video lectures recorded by Prof. Michael K. Stenstrom in collaboration with Dr. Diego Rosso from the University of California, US. In this course, the main parameters used to measure and assess the performance of aeration systems are presented. It describes their main features, characteristics, advantages and drawbacks in order to provide certain guidance for the selection of the most suitable aeration system in accordance to local operating and design requirements. Suggestions for sustainable aeration practices, such as energy conservation strategies, are also discussed and a design algorithm is introduced for the selection of an appropriate aeration system.
Time Framework for the Course: 1 week
Aims of the Course
- To discuss the main parameters usually applied to define and specify the performance and efficiency of aeration systems.
- To provide guidance for the selection of the most suitable aeration system for a defined application based on local conditions and on their main features and characteristics.
- To analyze the impact of different operating conditions and maintenance practices on the performance and efficiency of aeration systems.
- To analyze and discuss different strategies towards achieving sustainable aeration practices.
- To describe the characteristics of different aeration and mixing systems commonly applied in biological wastewater treatment plants and assess the impact of different conditions (design, operating and environmental) and maintenance practices on the aeration efficiencies.