Anwendung von Chlordioxid zur Beseitigung von Legionellen

Anwendung von Chlordioxid zur Beseitigung von Legionellen 

Zur Zeit läuft eine Untersuchung zur  Bestimmung der  Dosierung  von TwinOxide-Chlordioxidlösungen, um die Legionellenkonzentrationen  um ca. 99,999%  zu senken. Darüber werde ich später berichten.

Bekanntlich werden Chlordioxid-Lösungen auch aus zwei pulverförmigen Stoffen und Wasser hergestellt.

Im folgende  sind die Ergebnisse der Untersuchungen bei Siemens dargestellt, über die in folgender Quelle berichtet wird:

http://www.water.siemens.com/SiteCollectionDocuments/Product_Lines/Wallace_and_Tiernan_Products/Brochures/WT.085.272.017.IE.AN.0409.pdf

Cooling Systems - The ACoP, L8 guidelines state that chlorine

dioxide is effective for the control of Legionella when a residual

of 0.5 mg/L – 1.0 mg/L is maintained in the return water. The

effective concentration should be present for at least four out of

every 24 hours when chlorine dioxide is applied intermittently.

Under these guidelines, routine monitoring for the presence of

Legionella is required by an accredited laboratory. If the aerobic

count cfu/ml at 30°C (minimum 48 hours incubation) is 10,000

or less and the Legionella bacteria cfu/L is 100 or less, the

system is considered under control. If the Legionella levels are

higher than 100 cfu/L then appropriate action is required.

Hot and Cold Water Systems – The AcoP states that chlorine dioxide at levels of 0.5 mg/L can, if properly managed, be effective against planktonic and sessile Legionella in hot water system.

Feed Requirements

For control of bacterial slime and algae in industrial recirculating

and one-pass cooling systems, the required dosages will

vary depending on the exact application and the degree of

contamination present. The required chlorine dioxide residual

concentrations range between 0.1 and 5.0 mg/L. 

Chlorine dioxide may be applied either continuously or intermittently.

The typical chlorine dioxide residual concentration range is

0.1 - 1.0 mg/L for continuous doses, and 0.1 - 5.0 mg/L for

intermittent doses.

The minimum acceptable residual concentration of chlorine

dioxide is 0.1 mg/L for a minimum one-minute contact time.

Relative Effectiveness of Treatment

Alternatives

In general, the following comparison, in decreasing order of effectiveness, holds true for control and removal of bacteria by biocides present under the conditions described:

Bulk Water Bacteria: Biocide efficacy is dependent on the organism. For Legionella at neutral pH:

O3 > ClO2 ≥ HOCl ≥ HOBr

Bacterial Biofilms:

ClO2 >> HOCl ≥ HOBr > O3 > non-oxidizing

Algae:

ClO2 > certain non-oxidizing > HOCl > O3 > HOBr

Amoebic Cysts and Protozoa:

O3 > ClO2 >> HOCl > HOBr

( Dr.W. Storch-2013-09-30)