The response to aeration involves all aspects of the lake ecosystem: biotic and abiotic, internal and external. Total oxygen demand is the sum of respiratory and nitrogenous demands and is dependent on allochthonous, as well as autochthonous, organic matter. Layer aeration provides a cost-effective aeration alternative, especially in stratified eutrophic reservoirs with anoxic metalimnia and depth-selective supply withdrawal capability. It provides a mechanical means for reversing the ascent of compensation depth which occurred during eutrophication. Layer aeration uses available ambient DO sources (as in artificial circulation) while maintaining desirable temperatures and stratification stability. Hence, layer aeration takes advantage of the air lift function for depth-discrete mixing (like destratification) as well as the oxygen transfer from bubble to water (like hypolimnetic aeration).

Reprinted with Permission from Ecosystem Consulting Service, Inc.