ULTRASONIC sound waves are being used to kill off algae at an East Dorset reservoir.
Sembcorp Bournemouth Water (SBW) has installed an ultrasonic algae control system at Longham Lakes.
The system, supplied by Dutch company LG Sound, is used widely in mainland Europe but is the first to be installed by an English water company.
It uses underwater sound waves on scientifically proven frequencies to eliminate common algae, including toxic blue-green algae.
The ultrasonic waves 'pop' the air bubbles in the algae, causing it to lose buoyancy, sink to the bottom of the lake and die.
The environmentally-friendly system is run on solar energy, requires no chemicals and has no harmful effects for fish, water plants and insects.
The water in the lakes is extracted from the Avon and Stour.
Algae growth in the lakes can cause blockages which is why SBW needed to find a 'green' solution to the problem.