An ample oxygen supply in a wastewater pond system is the key to rapid and effective wastewater treatment. Bacteria need oxygen to allow their respiration reactions to proceed rapidly. Bacteria combine oxygen with carbon to form carbon dioxide. Without sufficient oxygen being present, bacteria are not able to quickly biodegrade the incoming organic matter. In the absence of dissolved oxygen, degradation must occur under septic conditions which are slow, odorous and yield incomplete conversions of pollutants. Under septic conditions, some of the carbon will be reacting with hydrogen and sulfur to form sulfuric acid and methane. Other carbon is converted to organic acids that create low pH conditions in the ponds and make the water more difficult to treat. For example, treated ponds designed to biodegrade wastewater pollutants without oxygen often must hold the incoming sewage for six months or longer to achieve acceptable levels of pollution removal. This is because the biodegradation of organic matter in the absence of oxygen is a very slow kinetic process.
The above video shows aeration of a pond