Sports centre eliminates Legionella and saves money on energy

Thanks to a Mini unit from Danish Clean Water (DCW), a sports and cultural centre on the Danish island of Als has eliminated Legionella from its water pipes as well as making savings on gas and electricity.

The Diamanten sports and cultural centre received the Danish Renovation Award (Renover-prisen) in 2014 for its transformation from a dilapidated sports hall into an attractive, energy-efficient sports and cultural centre. The comprehensive energy renovation included solar thermal collectors and a geothermal heat pump to produce climate-friendly domestic hot water.

However, the heat pump was unable to heat the water to above 50°C, and, for technical reasons, the old gas boiler, which was supposed to boost the temperature, could no longer raise the temperature enough either. This meant that biofilm grew in the water pipes and Legionella developed, with excessive bacterial counts as a result.

Mini unit rather than high temperatures

The centre manager considered using electric cartridge heaters to boost the temperature of the water to eliminate the bacteria, until a user at the centre suggested connecting a Mini disinfection unit from DCW to the centre’s hot water system.

“We started using the Mini unit in January 2023. Since then, the hot water has been free of biofilm and Legionella, and we can keep it at the 45°C it is when it has gone through the heat pump. Before installing the Mini unit, we had considered replacing the gas boiler with cartridge heaters to boost the temperature. The unit means that we don’t need to do any of that, saving us on both gas and electricity. It’s a win-win situation: the water is free of Legionella, and we save on energy costs,” says centre manager Jan Nielsen.

Jan Nielsen expects to scrap the gas boiler completely and instead invest in three air-to-water heat pumps for heating, as there is no longer a need to boost the water temperature to above 50°C.

“The boiler’s heat exchangers need replacing and that alone will cost DKK 20,000. A new boiler will cost DKK 60,000–70,000. We’d rather have air-to-water heat pumps to produce cheaper, efficient and green heat,” he explains.

Key benefits of the solution

Effectively removes biofilm and Legionella
Saves energy for heating the water
Is gentle and safe to use
Is easy to handle and maintain

Neuthox makes the difference

The Mini unit continuously adds a small, precise dose of the mild and effective disinfectant Neuthox to the water pipes. The active ingredient in the disinfectant is hypochlorous acid, which is produced from just water, salt and electricity.

“The health and safety of our users is of paramount importance to us. Before the unit was switched on, we shut down for 14 days and had all the pipes thoroughly flushed through with the Neuthox liquid to remove any old biofilm. Since the unit was connected, with the continuous dosing of the liquid, we’ve not had any Legionella,” says Jan Nielsen.

The Mini unit lives its own quiet life in Diamanten, where Jan Nielsen only periodically looks in to check that everything is as it should be. All he has to do is to check the figures for the operation and the bacteria levels in the water and occasionally fill up with salt.