Environmental Impact of Aeration
Total dissolved gas concentrations in water should not exceed 110 percent. Concentrations above this level can be harmful to aquatic life. Fish in water containing excessive dissolved gasses may suffer from “gas bubble disease”; however, this is a very rare occurrence. The bubbles or embolism block the flow of blood through blood vessels causing death. External bubbles (emphysema) can also occur and be seen on fins, on the skin, and in another tissue. Marine invertebrates are also affected by gas bubble disease but at levels higher than those lethal to fish.
Fine Bubble Aerator
Fine bubble aeration is an efficient way to transfer oxygen into water. Attached to a fine bubble diffuser are some emitters (diffuser) which produce fine air bubbles. The EPA (Environmental Protection Agency) defines a fine air bubble as anything smaller than 2mm in diameter.
Fine bubble diffused aeration can maximize the surface area of the bubbles and thus transfer more oxygen into the water per bubble. Additionally, smaller bubbles take more time to reach the surface so not only is the surface area maximized, but so are the several seconds each bubble spends in the water, allowing it more time to transfer oxygen to the water. As a general rule, smaller bubbles and a deeper release point will generate a greater oxygen transfer rate.
However, almost all the oxygen dissolved in the water from an air bubble occurs when the bubble is being formed. Only a negligible amount occurs during the bubbles’ transit to the surface of the water. This is why an aeration process that produces many smaller bubbles is better than one that makes fewer larger ones. The breaking up of larger bubbles into smaller ones also repeats this formation and transfer process.