Do you have cyanobacteria (toxic blue green algae) in your waterbody? Water mixing is a proven technique for ameliorating the development of blue-green algae blooms.
Most scientific studies on this technique have focused on deep water supply reservoirs where depths are greater than 10m. In these situations, successful results have been achieved. However, there is an increasing body of evidence suggesting that positive blue-green algae control can be achieved in shallower lakes. For this, a relatively vigorous mixing regime is pursued.
Diffuser based systems operate by creating columns of air rising from the diffusers to the lake surface. These act as air lifts drawing poor quality water from the bed and exposing it to the atmosphere where it is oxygenated. Circulation cells develop around each diffuser which is known as the primary mixing sphere. The primary mixing cell is a radial distance of 5 to 7 times the water so deeper waterbodies require less diffusers to mix the waterbody. Secondary circulation currents develop between the primary mixing areas, resulting in the entire waterbody being mixed.
Mixing of a lake tends to impact on blue-green algae bloom development in three key ways:
- 1. It increases dissolved oxygen concentrations in the lower water column helping with reducing internal nutrient loadings.
- 2. The system mixes the algae down to depth on deeper lakes where they become light limited. A similar effect may be achieved on a shallower lake through combining mixing with the use of lake dye.
- 3. A vigorous mixing regime disrupts the development of a bloom which seem to favour still water conditions.
Receive guidance on identifying toxic blue green algae.
Certain types of blue-green algae can be toxic to humans and lethal to animals. Learn more on the symptoms of toxic blue green algae poisoning to keep yourself and your loved ones safe.
There are further benefits to be gained from lake mixing, including the oxidation of organic material leading to consolidation of sediments. Our systems can also increase habitat availability by raising dissolved oxygen concentrations in areas of the lake bed where there are depressed oxygen levels. This reduces the concentration of bathing water bacteria by increasing exposure to UV radiation. Mixing can also prevent odour and ice formation.
The ISS Flowthrough systems are robust with a low maintenance requirement but do have an operational cost in terms of electricity supply and ongoing periodic maintenance.
If your waterbody has issues associated with stagnation, a diffused aeration system may be better suited.