Domestic hot water
Heating systems of hotels, hospitals, care homes and swimming pools, where hot water circulates continuously and the risk of Legionella is high.
Legionella control →
Disinfection
Chlorine dioxide
Chlorine dioxide is a powerful oxidant and disinfectant: it eliminates microorganisms, including Legionella, destroys biofilm and hinders its regrowth, and oxidises substances such as iron and manganese. It is an unstable compound: it is used in stabilised form or generated directly at the point of use.
- Effective against biofilm
- Active between pH 4 and 10
- Stabilised or generated on site
- Hydrochloric acid and sodium chlorite
0.1 – 1.0mg/lConcentration in water networks
4 – 10pHEffective range
30daysShelf life of activated stabilised product
2g/lConcentration produced by LOTUS
Applications
Where it is used
Drinking water
Water storage tanks of large public installations and treatment of well and spring water.
Drinking water →Industry and agriculture
Washing of bottles, fruit and vegetables, cooling towers, livestock drinking troughs, water for irrigation and plant nurseries.
Advantages
Why chlorine dioxide
Biofilm and Legionella
It destroys biofilm, which provides shelter and nutrients for bacteria, and hinders its regrowth: it is the most suitable disinfectant against Legionella.
Independent of pH
Effective between pH 4 and 10, with no loss of effectiveness; its action is not affected by corrosion inhibitors.
Residual effectiveness
It remains dissolved in water for a long time and also reaches the most remote or slow-circulating sections of the system, with a higher residual effectiveness than other disinfectants.
Rapid action
It disinfects in approximately 5 minutes of contact with the water.
No organohalogen compounds
It does not produce organohalogen compounds and, as it does not react with ammonia, it does not form chloramines.
Water unaltered
It does not alter the odour, colour or taste of the water.
Stabilised or on site
Stabilised or generated on site
Chlorine dioxide degrades very easily: for this reason it is used in two ways.
Stabilised chlorine dioxide
It is stabilised with an additional chemical component to allow storage and transport; the user activates it, manually or with a dosing pump, with an activator that releases its disinfecting power.
Advantages
- No production plant: it is dosed with a dosing station or with the LDsCL system.
Limitations
- Once activated it must be used within 30 days, with progressively decreasing effectiveness; any unused product must be disposed of.
- A few days after the drum has been opened, chlorites and chlorates may form.
Chlorine dioxide generated on site
A generator combines two precursors, hydrochloric acid (HCl 9%) and sodium chlorite (NaClO2 7.5%), and automatically produces chlorine dioxide at the point of use.
Advantages
- Always freshly produced, in small quantities, with virtually no by-products.
- Precursors far less expensive than stabilised chlorine dioxide: cost-effective in the medium term.
Limitations
- Cost-effective where water consumption justifies its adoption.
Production
How it is generated on site
In the LOTUS AIR generator, production takes place at ambient pressure, with fully automated and controlled cycles.
The LOTUS AIR production cycle →
Precursors
The control unit feeds water and the correct quantities of hydrochloric acid and sodium chlorite into the 1-litre reaction tank.
Reaction
In 15 minutes the two precursors react and form chlorine dioxide.
Dilution
Further water, free of free chlorine, brings the concentration to 2 g/l (2,000 ppm).
Storage and dosing
The chlorine dioxide passes into the integrated storage tank, from which one or more dosing pumps inject it at one or more points or into one or more systems.
Dosing and measurement
Dosing and measurement
The quantity of chlorine dioxide required depends on the oxidisable substances present: microorganisms, organic matter, iron, copper and manganese. When contamination increases, the residual falls and the system must dose more disinfectant.
Proportional to the water meter
The pulse-output water meter on the pipe controls dosing in proportion to the volume of water; it can also control the film-forming inhibitor pump.
Based on the measured residual
A self-cleaning amperometric cell measures the residual chlorine dioxide in mg/l and controls dosing up to the set point; combined with the water meter, it provides pre-dosing and correction based on the residual.
Amperometric cells →By signal or Redox
Constant dosing, proportional to a 4/20 mA signal or to the Redox potential measured by an electrode.
Safety
Safe production
Process control
The reaction takes place at ambient pressure and is continuously monitored; in the event of a malfunction, the drain valve discharges the chlorine dioxide.
Air sensor
It detects chlorine dioxide in the air of the room between 0.03 and 5.00 ppm: above the set point it triggers the alarm and stops production and dosing.
INAIL suitability
The LOTUS systems have received a statement of suitability for the safe management of water systems from INAIL (the Italian National Institute for Insurance against Accidents at Work): their installation allows a reduction of up to 28% in the annual INAIL premium.
Technical advice
Tell us about the system, the water consumption and the current treatment: we will assess whether to use stabilised chlorine dioxide or to generate it on site.