1. CHEMICAL TREATMENT

Intervention discouraged in plants dedicated to the transport of drinking water, as some traces of the chemicals used for the treatment may remain inside the system, compromising the potability of the water.

2. PHYSICAL TREATMENT 

THERMAL SHOCK: provides for a significant rise in water temperature, up to about 70-80 ° C [temperature which determines the rapid death process of the bacterium]. To be effective it is necessary to raise the temperature for at least 3 consecutive days and the water must run off at all points of the plant for at least 30 minutes. Due to the high temperatures required, this treatment cannot be performed with all types of pipes

THERMAL DISINFECTION: it is a process that is mainly applied to sanitary water distribution systems. The water in the system is brought to a temperature exceeding 50 ° C, thus reaching the temperature range in which the bacterium starts the progressive death.
To increase the effectiveness of disinfection, moreover, the water must periodically reach a temperature between 65 ° C and 70 ° C.

We also recommend a complete recirculation of the system [at a temperature between 55 ° C and 65 ° C] to be carried out daily for at least 30 consecutive minutes. Due to the high temperatures required, this treatment cannot be performed with all types of pipes


             
                                                                                                                            
             WATER TEMPERATURE                    COMPLETE SYSTEM                         RECIRCULATION FOR 
                   RAISING                                     RECIRCULATION                      30 CONSECUTIVE MINUTES




Water temperatures

 

25°C -50°C : development 
35°C -45°C : critical range of development and proliferation
>55°: beginning of the progressive death of the bacterium
70°C -80°C :rapid death rate of legionella


 

Spread

 

These are the main conditions that favor the spread of the Legionella bacteria:
 
water stagnation;
• presence of scale and sediment;
biofilm [micro-organism aggregation];
• presence of amoebae [single-celled organisms].
inadequate water circulation temperatures in the system

Precautions

 • limit unforeseen overheating (eg through insulation of pipes, correct positioning of hot and cold water pipes ...)
• organize the production and storage of hot water at temperatures above 65 ° C;
• guarantee an adequate recirculation line to support hot water and let it flow before using it;
• provide for the maintenance and cleaning of taps, shower diffusers and water storage tanks
• avoid sources of emission of water vaporized outside homes