Prevention of (blue-green) algae in drinking water sources

Algae and blue-green algae (Cyanobacteria) typically cause problems in summertime: they thrive in stagnant or slow flowing warm water with high levels of nutrients that is exposed to sunlight. Algae can make the water pH rise or cause blockages in the piping. But especially blue-green algae are a threat to animal health. When the layer of blooming algae starts to decompose, toxic substances are released. These toxins can cause a wide range of health problems, from mild to lethal. Consequently blue-green algae can indirectly promote unnecessary use of antibiotics.

Once algae have started to bloom, there is no way back. Prevention is the key to cope with algae. When drinking water supplies are stored in a basin, different techniques can be used to prevent algae growth.

Light shielding: this is the most efficient method as algae cannot survive without light. The water surface can be protected from light with a (floating) sail or if this is not possible, floating balls/hexagons. A regular check-up of the shielding is strongly recommended.

Aerating/stirring the water: This inhibits algae growth by increasing the oxygen levels in the water (aerating) and creating water flow (stirring).

Ultrasonic sound waves higher than 20kHz are an effective method to kill present algae and prevent their growth.

Certain water plants prevent algae growth by production of substances that prevent or slow down algae growth. Other plants compete with the algae for nutrients in the water, thus inhibiting algae growth.