Des P037/en Coolant water disinfection in major industrial plants © SANOSIL 1/8

Sanosil C (cooling tower) Disinfection of coolant water

in major industrial plants

SANOSIL AG., CH- 8634 Hombrechtikon, Schweiz Tel.: 055 254 00 54, Fax: 055 254 00 59 E-Mail: info@sanosil.com, Internet: www.sanosil.com

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Des P037/en Coolant water disinfection in major industrial plants © SANOSIL 3/8

What is SANOSIL C?

SANOSIL C is a patented hydrogen peroxide and silver-based disin-

fectant with strong bactericidal, algaecidal and fungicidal properties.

Hydrogen peroxide is a strong oxidizing agent which releases oxy-gen molecules (atomic oxygen) and destroys membrane structures

in microorganisms.

Silver interferes with basic bacterial metabolic functions (enzymes)

and has an excellent long-term effect.

The two main ingredients exert similar effects and these are multiplica-

tive (potential synergy).

Mode of action: The main active ingredient is environ-mentally friendly hydrogen peroxide,

which undergoes a sophisticated stabili-

sation process and has its efficacy against microorganisms further en-

hanced by the addition of silver. The result is an antimicrobial effect many

times greater than that of normal hy-

drogen peroxide. The tiny amounts of silver left on the surface help to prevent

recolonisation.

[[Legend: Hydrogen peroxide destroys the cell wall

Silver blocks the microorganism’s ability to di-vide/reproduce and obtain energy]]

On coming into direct contact with it, the elemental oxygen (O2) produced by the hydrogen peroxide attacks

the microbial cell wall. The oxygen reacts with molecules in the cell wall, leading to its denaturation and de-

struction. The effect is enhanced by silver ions, which bind to sulphur bridges in specific microbial proteins, resulting in their inactivation.

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Sanosil C - effect on biofilms: Thanks to the method used to stabilise the hydrogen peroxide in Sanosil C, it achieves a much improved

effect against biofilm structures. Stabilisation allows the peroxide to penetrate the biofilm matrix rather than decomposing immediately. The effect is like that of an explosive charge with a time delay fuse – the decom-

position of the peroxide actually within the biofilm physically tears it apart.

1. Stabilised hydrogen peroxide (blue) comes into contact with the biofilm structure (brown)

2. Thanks to their stability, the peroxide molecules are able to penetrate the film struc-ture

3. The peroxide which has penetrated the film

begins to release oxygen

4. The oxygen bubbles come together, expand in volume and blow the biofilm apart.

Good to know: A 0.02 mm biofilm layer provides the same level of thermal insulation as a 2 mm layer of limescale.

Biofilms also provide excellent protection for bacteria such as Legionella, which are difficult to control using

standard methods or require the use of very high dose biocides.

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Properties and advantages: SANOSIL C...

has no gaps in its spectrum of activity and is active against all types of bacteria (including filamen-tous bacteria), yeasts, fungi and protozoa

is highly effective against biofilms (dual-phase product)

does not react with ammonium ions (no decomposition)

by releasing oxygen, largely prevents anaerobic conditions from arising in coolant water. This impedes the growth of sulphate-reducing bacteria (formation of corrosive hydrogen sulphide: 4 H2 +

SO42-S2-+ 4 H20).

has a very good long-term effect and reliably prevents recolonisation

has no significant corrosive effect

produces no breakdown products

is environmentally friendly and almost 100% degradable (2H2O2 = 2 H2O + O2)

can be measured and controlled instantly

we offer a full range of products for industrial plants

has a very long shelf life, with a maximum drop in concentration of approx. 3% per year

its use requires negligible amounts of equipment/investment

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Two examples of the biocidal effect of Sanosil C Cooling tower in Switzerland:

Cooling tower in Germany:

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Environmental impact: Sanosil C has an excellent environmental compatibility profile. In contrast to other products, its use produces no trihal-omethanes or other problematic compounds. Example: AOX measurement at a cooling tower in Switzerland:

AOX measurement at a cooling tower in Switzerland after using sodium hypochlorite:

AOX measurement: AOX g/l

Untreated water 23

Primary coolant water before addition of NaOCl 73

Primary coolant water 1 hour after addition of NaOCl 151

Primary coolant water 4 hours after addition of NaOCl 122

AOX measurement at a cooling tower in Switzerland after using Sanosil C:

AOX measurement: AOX g/l

Untreated water 5

Primary coolant water before treatment with Sanosil C 16

Primary coolant water during continuous treatment with Sa-nosil C

16

Good to know: AOX = adsorbable organic halogens. These include chlorine, bromine and iodine compounds, some of which have the potential to cause serious environmental and health problems.

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Disinfection of cooling tower water Comparison of microbicides

Cl2 Non-continu-ous

ClO2 Non-continu-ous

Cl2/Br Non-continu-ous

O3 Continu-ous

O3 Non-continu-ous

Organic biocides

Sanosil C

Efficacy + + + ++++ ++ ++ +++

Efficacy at pH > 8 -- + + ++++ ++ (++) ++

Investment + - ++ -- -- +++ ++++

Operating costs ++ + - ++ ++ --- +++

Cost of equipment + - ++ -- --- +++ ++++

Health and safety -- --- + - -- - +

Recolonisation + + + ++ -- - +++

Breakdown prod-ucts

AOX Chlorite Bromate Insignifi-

cant

Insignifi-cant

Metabo-lites

none

++++ Excellent +++ Very gut ++ Good + Adequate - Inadequate -- Poor --- Very poor

More detailed information on SANOSIL C can be found in the SANOSIL document DES P 29/de “Use of SANOSIL C in cooling towers”.