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Waste Water Treatment

  1. Arnim R. H. Hertle

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.ww6

Water Encyclopedia

Water Encyclopedia

How to Cite

Hertle, A. R. H. 2005. Aeration. Water Encyclopedia. 1:623–626.

Author Information

  1. GHD Pty Ltd, Wembley, Washington, Australia

Publication History

  1. Published Online: 15 JUL 2005


The aeration of wastewater and byproducts is a key process in the operation of most modern wastewater treatment plants (WWTP), which is reflected in the energy consumption of a WWTP's aeration system, which can be up to 70% of the WWTP's total energy consumption.

As most wastewater treatment plants and many sludge treatment plants include aerobic biological processes, the transfer of oxygen into the wastewater (or sludge) is a key operation.

As a result of the large quantities of CO2 produced in the course of the aerobic degradation of organic matter, the pH in such a reactor can be significantly lower than that of its feed. These CO2-related effects can be amplified when nitrification occurs or when the liquor's alkalinity is low. This drop in pH can lead to decreased performance of the plant as well as to impacts such as concrete and metal corrosion if not managed properly. The second key function of an aeration system is therefore to remove CO2 from the reactor (1).


  • wastewater;
  • aeration;
  • aeration efficiency;
  • oxygen transfer;
  • fine bubble diffusers;
  • coarse bubble diffusers;
  • mechanical aerators;
  • surface aerators;
  • submerged aerators;
  • membrane diffusers;
  • ceramic diffusers