Blue-green algae, or cyanobacteria, are the most ancient of all photosynthetic organisms. Some produce poisons that are harmful to humans and possibly fatal to domestic animals and fish – neurotoxins and liver toxins and skin allergens.

Algal blooms can cause waters to be unsafe for all users and uses including agriculture, irrigation and recreation.

It is essential that all persons affected by blue-green algae understand what it is, and what the potential impacts of the algae may to them or their business or recreational activities.

Algae is a form of plant life that grows in both fresh and brackish water. Growth becomes excessive when the combination of three environmental conditions sunlight, temperature and nutrients become optimum.

Sunlight and temperature are two prime drivers of algae growth, the third being nutrients including nitrogen and phosphate. As little as 0.01 mg / L of phosphate will stimulate growth. Removal of any one of these drivers will inhibit algae growth.

Algae growth is most likely to occur when:

• the water is calm
• the water temperature is warm (above 20 degC)
• there is low to zero flow
• the water is fairly clear
• pH is slightly alkaline
• the water is stratified in temperature layers that do not mix.

There is a considerable range of algae species found in fresh water. These include green algae, blue-green algae, diatoms, dinoflagellates and cryptomonads. All algae blooms can cause water use problems. However, those caused by blue-green algae are the most concerning as a number of these are toxic. For further information on the toxicity impacts refer to the NSW DPI Prime Fact No 1506.

Algae will not grow in darkness, so cover the top of water storages susceptible to blue-green algae.
Covering the water surface also reduces water temperature increase by eliminating radiant sunlight.
Artificial aeration circulates cooler water to the surface, de-stratifying temperature layers in the water while increasing oxygen concentration and maintaining a cooler overall temperature of the water.

Blue – Green Algae minimization with QUIT EVAP.

The QUIT EVAP evaporation mitigation technology, comprising large modular panels of opaque fabric reduces sunlight penetration and radiant energy impacting the water by 95 %, thereby providing a highly effective inhibitor of blue – green algae growth in water storages.

QUIT EVAP EMT, used in conjunction with bottom based bubble aerators which de-stratify thermal water layers and oxygenate the water possibly provide an optimum solution to blue-green algae occurrence.

Reference: NSW Department of Primary Industries. Prime Fact 1506 May 2017, third edition. Farm Water quality and Treatment: Algae.