Let's look at the issue in ...

Let's look at the issue in two parts: 

1. The formation of scale in pipework and cooling towers.

2. The growth of Legionella bacteria on the scale substrate.

The removal of scale can be solved chemically, my company has developed and manufactures a green-rated, non-toxic and cost effective pipe scale remover called 'Clean Pipe Extra.' This is a safe and non-acidic approach which will not damage the seals, fittings, pipework and other equipment in the cooling system. The control of future formation can be managed through control of pH through the use of water softeners. We have experience in developing ongoing scale and corrosion control strategies for cooling towers and water distribution networks for HVAC and potable water supply. 

It is worthy to note that the removal of scale will not necessarily solve your Legionella issue. The reason being is that the 'biofilm' colonies which house and protect the Legionella bacteria from disinfectants can form and grow on any surface within the network, even on the smoothest of surfaces. To effectively control Legionella, you will need a multi-barrier approach which combines preventative technologies, efficient chemical dosing and routine monitoring.

Research has shown Legionella to be resistant to thermal shock, high chlorine or biocide dosing, and UV irradiation because of their ability to survive inside amoeba and be protected by the biofilm colony that is formed. That is why Legionella outbreaks still exist in cooling towers of buildings in 1st world countries, even with routine monitoring and chemical control. New methods of prevention need to be considered in these situations. We have found in research that mechanical disinfection through hydrodynamic cavitation is the most effective way in breaking apart the biofilm layer, amoeba and Legionella bacteria cell wall. If the Legionella is not instantly killed, it will be killed with a minimal amount of residual chlorine or free radicals generated in the water. My company has developed an effective strategy currently used in Europe, Asia and Australia to prevent and control the growth of Legionella in cooling towers using this method of disinfection without costly chemicals combined with the efficient removal of organic microparticles and dissolved metal nutrients that feed bacteria.

If you are interested, please send me an email at andrew@waterandoilsolutions.com.au and I will be happy to send you any information you need and set up a time to speak over the phone or on Skype.