Aeration versus Oxygenation

The words aeration and oxygenation are unfortunately and incorrectly used interchangeably. There is a considerable difference between the two and it is important to understand this difference.


Air contains roughly 21 per cent of oxygen and 79 per cent nitrogen and other trace gases. Nitrogen makes little or no contribution to water treatment. Oxygen on the other hand is an essential component in the biological process. Without oxygen life cannot exist.

Dependent upon its temperature and composition, water can carry a limited amount of free oxygen (up to 15 ppm), which is expressed as dissolved oxygen content (DOC). Bacteria absorb this oxygen and fish extract it through their gills.

Bacteria - oxygen supports bacteria and other life forms. In aquatic ecology and wastewater applications bacteria plays a vital role in maintaining balance and preventing pollution by digesting many kinds of putrescence. Oxygenation is essential to fuel this process. Bacteria are extremely efficient when it comes to extracting oxygen from water and fish and other higher life forms will always come second in this race for life. It is therefore essential that oxygen levels are adequate to deal with the fluctuating demands of climate, natural and man-made pollution and the requirements of all kinds of aquatic life.

Without a residue of oxygen an anaerobic condition will prevail generating polluting solids and gases. In wastewater applications oxygen is delivered to accelerate nature's process of digesting contaminates, essentially converting them to water and inert gases. It is therefore vital to maintain a constant supply of oxygen in a manner that enables wide distribution and metabolic assimilation. The MANNER of oxygen delivery is critical! Just throwing oxygen or air into water is wasteful and ineffective. The Airmaster Aquafoil uses aerospace technology to conquer this challenge providing the most efficient means of oxygenating wastewater.

Fish - If the DOC level is deficient fish suffer in a similar way to humans at high altitudes. Short of this "metabolic fuel" energy is drawn from within the creature's body and an anaerobic chain reaction occurs. Acid accumulates in tissue (similar to cramp in humans) and stress negatively affects behaviour patterns and health. Lack of oxygen for an extended period will of course result in death.

In aquaculture tanks and cage farms where high stocking density conditions exist oxygen supply and demand are critical factors. Marginally lower levels DOC can limit swimming and feeding activity, retard growth and lead to aggressive behaviour. Oxygen demand varies according to climatic conditions and bacterial activity. It can increase significantly during feeding and fluctuate significantly with temperature change.

Consequently it is essential to maintain a continuous supply of oxygen in a manner that can enrich the water. DOC saturation levels limit the amount of oxygen that water can hold and the depletion rate in high-density tanks can be extremely challenging.


The term aeration is widely used and describes the practice of putting air and water together in the expectation of transferring oxygen. These expectations are frequently over optimistic. There are two basic approaches.

Putting water into air - Throwing water into the air (fountains) or moving it about at the surface (agitation) are common forms of Aeration. While these widely used methods make a dramatic display and may appear effective the oxygenation effect is both limited and expensive. The amount of energy used can be excessive for the amount of oxygen transferred.

As every schoolboy knows, pure water contains two molecules of hydrogen and one molecule of oxygen (H2O). However, small amounts of free oxygen can be held at within this structure dependent upon temperature, atmospheric pressure and other materials that it contains (salt, calcium, other minerals and materials). These are dissolved within the structure of the water and the quantity of free oxygen it can hold can vary up to a saturation level of 15 milligrams per litre (mg/l) - or expressed in different units 15 parts per million (ppm).

This tiny amount is all that is available to support life in its many forms. At ground level air contains approx. 21 per cent oxygen and this level is maintained across the surface of the planet by global environmental conditions. The transfer of oxygen from air into water is a process few understand and many take for granted. Just throwing water into the air and expecting the oxygen to instantly migrate into the water is frankly - just wishful thinking.

Putting air into water - Air contains only 21 per cent of oxygen and the balance of this global gas makes a negligible contribution to water. Many companies focused on "aeration" as opposed to oxygenation, seem to neglect this fact. Air pumps, blowers, compressors and diffuser systems expend energy delivering a fluid with only 21 per cent active ingredients into water. In addition, blasting air through water does not necessarily achieve the desired effect - large bubbles can maintain their structural integrity and pass through water without leaving behind any oxygen.

Airmaster's innovated mechanism combines oxygen and water by delivering microscopic air bubbles into the turbulence within the water flow that induces the air. This energy efficient method of oxygenation draws upon the aerodynamics employed by aircraft manufacturers and outperforms other means of "aeration". One independent study showed that the Airmaster method could perform at one third the cost of its nearest rival method and was more than five times more cost effective than other techniques.

As the registered patent holder and developer of this unique device Airmaster is able to provide specific advice and customs solutions for a wide range of applications.