Normally, this blog focuses on ozone and advanced oxidation technologies for water and air treatment. An interesting non chemical water treatment for algae control might be of interest to the readership of the blog.
Algae blooms can create both aesthetic and other problems for tanks, ponds and lakes. Chemical treatments are routinely used, but require adding toxic chemicals to the water and in safe doses might not always be effective. An alternative is the use of ultrasound.
The complex pattern of ultrasonic vibrations through the water causes the algae vacuole cell wall to resonate and break, much like a glass breaking from a high pitched sound. The broken vacuole wall eliminates algae’s ability to grow and reproduce, while the same vibrations are harmless to humans, animals, fish and other aquatic plants. The discovery that ultrasound waves in water kill algae was made over sixty years ago in submarine sonar experiments. the Navy discovered that surfaces impacted by the sonar waves did not accumulate algae as other areas not covered by algae did. This eventually led to the study of the phenomenon for algae control.
It is important to note that ultra sound alone might not be enough to solve all of the problems associated with a pond or lake. Even if the algae is killed, the pond might not contain enough bacteria or oxygen to break down the organic matter found in the water, including the algae killed by the ultra sound system. So, proper control of algae requires a balanced ecosystem which has sufficient oxygen and proper bacteria present in conjunction with the ultrasound.
Another issue is that some algae do not have the same physical structure as other algae and thus are not affected by ultrasound. Prior to applying ultrasound, the algae in a given body of water should be tested to make sure that it does not contain these algae species.
Although the method has some limitations, ultrasound algae control offers an economical treatment option for small bodies of water that has been used in a wide range of ponds, lakes and water treatment facilities.