Eagle-eyed visitors to Hanningfield Reservoir in Essex or Ormesby Broad in Norfolk may have noticed small yellow devices floating on the water.
The devices that resemble 'yellow spaceships', are being trialed to help improve water quality and re-establish healthy ecosystems functioning; this can help to manage algae growth that can form in water during the warmer summer months.
Essex & Suffolk Water has placed the three approximately half-metre wide, yellow spaceships in Hanningfield reservoir at specific points to make them as effective as possible. One has also been placed in Ormesby Broad in Norfolk.
The solar-powered, self-sustaining devices emit a very low-power signal (less than 1 watt) that changes how the water behaves at the surface. This can double the rate of gas transfer between the air and water, helping to moderate pH and increase dissolved oxygen availability.
This helps support the ecology conditions and creates conditions that favour the production of algae-eating zooplankton. This, in turn, naturally reduces algae concentrations, and encourages the habitat to re-establish natural ecosystem function and processes.
Chris Fulton, Head of Water Supply at Essex & Suffolk Water, said: “The spaceships are one of five methods we are using to form a multi-pronged innovative approach to help manage the algae in the reservoir.
“We know we won’t be able to completely prevent algae, but algae blooms happen when the weather is warm and calm, so it has become something we need to manage going forward.
“This is important because the algae can cause problems within the mechanisms of the water treatment works and slow down the amount of water the works can process in a 24-hour period.
“This six-month trial will give us a better idea of what works and what doesn’t so we can invest in a longer-term solution and keep the water flowing.”
The yellow spaceships, officially called the “Equilibrium Modulating Fluids (EMF) Device”, have been used in over 20 countries around the world, but this is the first time they have been tested in the UK for drinking water reservoirs.
Natural England have been involved due to Hanningfield Reservoir being a Site of Special Scientific Interest (SSSI).