UV Disinfection

The Science of UV Light
Ultraviolet Sterilization is unmatched in its efficiency, simplicity, and dependability when applied as a microorganism disinfectant. UV sterilization is a proven solution to waterborne planktonic algae as well as other harmful pathogen problems. Certain critical UV performance factors greatly affect all UV sterilizers, no matter who’s the manufacturer. The information contained in this outline should be considered before purchasing any UV equipment .
Factors Influencing UV Effectiveness

Whether you choose to label a UV as a clarifier or a sterilizer, the same design, performance, and operating principals apply. Successful UV operation destroys the targeted microorganism. Here are five main factors that will help determine the ability of a UV sterilizer (or clarifier) to achieve this desired effect.

1. The type of lamp used in the application. (low-pressure or medium/high-pressure)
2. The length of the lamp being used. (the ARC Length)
3. The physical design of the UV’s water exposure chamber.
4. The condition of the water being treated.
5. The water flow rate through the UV’s exposure chamber

The Science of UV

Let’s start at the beginning. Ultraviolet light is a spectrum of light just below the range visible to the human eye (below the blue spectrum of visible light in the chart above). UV light is divided into four distinct spectral areas-Vacuum UV (100 to 200 nanometers), UV-C (200 to 280 nanometers), UV-B (280 to 315 nanometers), and UV-A (315 to 400 nanometers). The UV-C spectrum (200 to 280 nanometers) is the most lethal range of wavelengths for microorganisms. This range, with 264 nanometers being the peak germicidal wavelength, is known as the Germicidal Spectrum.

The Targeted Microorganism

It is critical to first identify the microorganism. Each type of microorganism requires a specific UV-C radiation exposure rate to successfully complete the disinfection process. The targeted microorganism must be directly exposed to the UV-C radiation long enough for the radiation to penetrate the microorganism’s cell wall. However, it takes only seconds for UV-C light rays to inactivate waterborne microorganisms by breaking through the microorganism’s cell wall and disrupting their DNA. This often totally destroys the organism, or at the very least will impair its ability to reproduce.

The UV Lamp… the Source of UV

UV light sources primarily come as low-pressure or medium/high-pressure lamps. Low-pressure lamps produce virtually all of their UV output at a wavelength of 254 nanometers-very close to the peak germicidal effectiveness curve of 264 nanometers. These lamps generally convert up to 38% of their input watts into usable UV-C watts. This is much higher than other classes of lamps. (i.e. a 150-watt low-pressure lamp will have approximately 57-watts of UV-C power.) Low-pressure lamps typically run on low-input power currents of 200 to 1,500 milliamps and operate at temperatures between 100 and 200 degrees Fahrenheit. They have a useful life of 8,000 to 12,000 hours depending on the operating current of the lamp.

Medium/high-pressure lamps produce wavelengths widely ranging from 100 nanometers to greater than 700 nanometers, well into the visible light spectrum. These lamps are very poor producers of usable germicidal wavelengths; they generally convert only up to 8% of their input watts into usable UV-C watts. (i.e. a 400-watt medium-pressure lamp will have approximately 32-watts of UV-C power. The remaining 368-watts are converted into heat and visible light.) Medium/high-pressure lamps typically run on high-input power currents of 2,000 to 10,000 milliamps and operate at temperatures between 932 and 1,112 degrees Fahrenheit. They have a useful life of only 1,000 to 2,000 hours depending on the lamp’s operating current. As you can see from these comparisons, low-pressure lamps perform safely and efficiently. They are the better option for use in UV sterilization.

Low-pressure UV lamps come in many different styles and lengths. As a general rule, the longer the lamp, the greater amount of UV the water will receive because it will be exposed to the UV source for a longer period of time.
UV Lamp Length + UV-C Output + Useful Lamp Life = Lamp Value

• UV lamp length is a critical performance factor that helps establish UV exposure.

• Evaluating UV lamp performance based on input watts is inaccurate! The “Input -vs- UV-C output Watts Chart above demonstrates the poor germicidal value of med-pressure lamps compared to low-pressure type UV lamps. Low-Pressure UV lamps convert approximately 38% of their input watts into UV-C output watts while the medium-pressure UV lamps convert 8%. Low-pressure style UV lamps offer greater germicidal value than medium pressure lamps for this reason.

• Knowing when to replace UV lamps is critical to achieving a consistent UV disinfection dose, but not all lamps offer the same useful operating life!

Design of the Water Exposure Chamber
The design of the water exposure chamber is completely overlooked by some manufacturers, but it is key to successful operation. The distance UV light energy has to travel from the surface of the lamp to the inner wall of the UV’s water containment vessel determines how much UV the water will receive. This is known as the “UV dose rate.” The amount of water passing through the UV filter ultimately determines the unit’s actual UV dose rate, which is expressed in microwatt’s per second per square centimeter or (u-watts-sec/cm2). When selecting a UV Sterilizer for your application:

• Make sure the UV lamp is positioned between the water inlet and outlet ports of the unit’s water containment vessel. Any portion of the UV lamp(s) not located between the water ports is useless. When calculating the UV’s performance data, only the ARC length located between the water ports can be applied to the calculation, reducing its capabilities if portions of the lamp are not between the ports.

• Select the unit with the largest diameter water containment vessel in the wattage you are considering. A unit with a larger diameter will always have a greater contact time. (For example, a 25-watt model with a 3″ diameter housing will flow more water than a 2″ housing model.)

Single UV Lamp Array Diagram

Multiple UV Lamp Array Diagram

Open-Channel UV Lamp Array Diagram

• Make sure the unit you are considering uses a quartz sleeve. A quartz sleeve isolates the UV lamp from the water to avoid a short circuit path for the lamp’s electrical power. It also allows the lamp to operate at its optimum temperature by acting as an insulator.

• Does the manufacturer list water flow rates at the end of a lamp’s life or the beginning? Most UV manufacturers give a water flow rate, but do not indicate whether it applies to a new lamp or to one that is at the end of its useful life. Try to find a manufacturer that includes the water flow rate in the unit’s end of lamp life rating. The end of lamp life rating takes into account the lamp losing UV-C output due to age so it is a more realistic prediction of how the unit will perform.

• Do the manufacturer’s water flow rates account for the reduced effectiveness UV light has when treating green water? This information should be listed as some type of percent transmissibility rate or absorption coefficient (decimal value). Units that account for green water will have lower water flow rates.

UV Transmittance
UV transmittance is also largely overlooked, but it is one of the most critical factors in determining the ability of a UV sterilizer to treat a given volume of water. Regardless of the type of UV light source used, any body of water containing impurities will adsorb UV energy. Green water, water plagued by algae and microorganisms, will absorb the UV energy emitted by our UV light source in proportion to its density (or how green the water is). The greater the amount of algae in the water, the more of a reduction in percent transmittance. Percent transmittance is the ability of a body of water to be effectively treated by a UV light source. This value indicates the quality of the water being treated. The higher the percent transmittance, the easier the UV sterilizer will be able to treat the water at a given flow rate. A lower percent transmittance means the UV sterilizer will be less effective in dealing with the algae problem. If the sterilizer’s water flow rates have not been calculated with a reduced percent transmittance rate, the unit will have considerable trouble dealing with an algae bloom.
Water flow rate through the UV’s contact chamber
A sound UV sterilizer design revolves around the careful selection of lamp type, lamp length, lamp position, and body diameter. These factors, together with the intended water flow rate, percent transmittance of the water to be treated, and UV dose rate needed to kill the targeted microorganism should be your basis for the selection of a unit for your pond. When researching which type of UV sterilizer to purchase, remember the criteria laid out in this article, read the manufacturer’s literature, ask questions, and most of all ask yourself, does this information make sense to me? If not, conside

another UV manufacturer.

Press Presse Prensa
Industrial Solutions
and Services
I&S Press Office / Roland Hensel For “Archiv des Badewesens“,
Issue January 2008
Degradation of nitrogen chloride compounds in swimming pool water by means of UV radiation – An examination of the literature
Georg Csontos, Rob van Esch, Robert Kappel
Siemens Water Technologies, Wallace & Tiernan GmbH, Auf der Weide 10, D-89312 Guenzburg, Tel. +49 8221 904 -216, E-Mail: Georg.Csontos@siemens.com
Chloramines in swimming pool water are produced due to the effect of chlorine products on urea or ammonium nitrogen. However, there is no direct method of analysis for bound chlorine. It has to be calculated from the difference between total chlorine and free chlorine. This article indicates the ways in which chloramines are produced and describes the occurrence of different chloramine species in swimming pool water. In addition, different reaction mechanisms for the degradation of chloramines are described. These mechanisms explain why polychromatic UV light from medium-pressure lamps is successful at eliminating nitrogen chloride compounds.
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1 The origins of chloramines in swimming pool water
Public swimming baths are disinfected by adding free chlorine. However, apart from the desired effect of its killing unhealthy germs, the free chlorine also produces undesirable by-products due to the incomplete oxidation of organic substances. Among the most frequent of these by-products are nitrogen chloride compounds or chloramines which are formed in swimming pool water due to the interaction between free chlorine and urea. The most important precursor for chloramine formation is urea from anthropogenic sources. This urea comes from urine, sweat and peeled-off parts of the skin’s horny layer. A swimmer can deposit between 1.5 and 2.5 g of urea in the swimming pool every hour.
H2N NH2CO+ 2 HOCl=>CO2+2 N+ H2OUreaChlorineCarbon dioxide Monochloramine WaterH ClH
Fig. 1 Formation of monochloramine
Monochloramine is the starting material for the formation of dichloramine and trichloramine.
H
Cl
N
H
Monochloramine
+
HOCl
=>
Cl
Cl
N
H
+
H
2
O
Dichloramine
Fig. 2 Formation of dichloramine
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Monochloramine is initially formed in the pH range from 6.5 to 7.6, which is relevant for swimming pool water. Once the ammonium nitrogen present in the water has been almost completely transformed, monochloramine continues to
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react to form dichloramine (NHCl2). The ratio of monochloramine (NH2Cl) to dichloramine depends on the pH value in the water. Fig. 3 shows how the balance of different chloramines in the water depends on the pH value. In the normal pH range of swimming pool water, namely between 6.5 and 7.6, the chloramine is almost completely made up of monochloramine. At higher pH values, the proportion of dichloramine decreases and that of monochloramine increases accordingly.
pH range of swimming pool water
[%]
6
5
100
90
80
70
60
50
40
30
20
10
0
18
96
98
100
4
2
0
7
8
9
NH2Cl
NHCl2
[pH]
82
48
52
Ratio of monochloramine to dichloramine
depending on the pH ratio of swimming pool water
Fig.. 3 The balance between monochloramine and dichloramine in relation to the pH value, according to /4/
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0 20 40 60 80 10012 34 5678pHTotal bound chlorine (%)MonochloramineDichloramineTrichloramine
Fig. 4 Distribution of chloramine species in relation to the pH value /2/
Trichloramine is an undesirable by-product of disinfection. It causes inflammation of the eyes and the mucous membranes. Due to its high vapor pressure and poor solubility in water, it degasses easily from the swimming pool water.
In the pH range between 6.5 and 7.6 which is relevant for swimming pool water, trichloramine cannot be formed from monochloramine and dichloramine as the latter two substances are in balance as a consequence of the pH value. Trichloramine is not produced through the chlorination of dichloramine (Fig. 5). Figure 4 shows the distribution of the chloramines in water in respect of different pH values. This indicates that trichloramine cannot be formed from the reaction with monochloramine and dichloramine in swimming pool water because the pH value of the water is at least 6.5 and is therefore far above the pH range in which trichloramine can exist, namely pH <= 4.0.
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ClClNHDichloramine+HOClpH < 4ClClNCl+H2OTrichloramine
Fig.5: Mechanism of trichloramine formation under acidic conditions not occurring in swimming pools
On the basis of sources within the literature, Stottmeister und Voigt /6/ describe a plausible manner in which trichloramine is produced:
According to these two authors, urea tetrachloride and not dichloramine is the starting substance for the formation of trichloramine. The reaction involves the chlorination of urea tetrachloride to form trichloramine, thus avoiding the long route via monochloramine and dichloramine (cf. Fig. 7).:
H2N
NH2
C
O
+ 4 H
OCl
=>
+ 4 H
2
O
urea
Urea tetrachloride
water
Cl2N
NCl2
C
O
chlorine
Fig.. 6 Formation of urea tetrachloride as a precursor of trichloramine
Cl2N
NCl2
C
O
+ 2 H
OCl
=>
CO
2
+ 2
N
+ H
2
O
Urea tetrachloride
chlorine
Cl
Cl
Cl
Carbon dioxide Trichloramine water
Fig. 7 Production of trichloramine from urea tetrachloride in a neutral milieu
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The reaction described by Stottmeister and Voigt explains why trichloramine also occurs in the neutral pH range stipulated by DIN for swimming pool water. They describe investigations according to which a diluted aqueous trichloramine solution has a half-life period of 218 minutes at a pH value of 7 which means that 50 % of the substance breaks down in water within three and a half hours at a pH value of 7. The degassing factor of a diluted aqueous trichloramine solution thus is just under 1000 times higher than that of monochloramine. Larger water surfaces such as slides, water mushrooms, etc. promote this additionally. The fact that the amount of chlorine bound in swimming pool water is in accordance with DIN does therefore not mean that the concentration of trichloramine is negligible in terms of its effects on health.
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3 The problems of using chlorine in the presence of ammonium nitrogen for the supply of drinking water
Fig. 8 below shows how the addition of chlorine to water containing ammonium initially increases the chloramine species in the water.
Free chlorine
Fig.. 8 Diagram of the inflexion point of chlorination in relation to the chorine content per mg NH4-N according to /2/
Chlorine dosis
The chloramine content does not increase at constant rate when chlorine is added. From 5 mg of chlorine per mg of NH4-N upwards, the chloramine content decreases and reaches a minimum value at a specific content of 7 mg of chlorine per mg NH4-N. Above a specific content of 7 mg of chlorine per mg of NH4-N, the chloramine content increases again. If the chlorine added amounts to less than 7 mg per mg of NH4-N, there is practically only monochloramine and dichloramine in the water. Above the ratio of 7 mg of chlorine to 1 mg of NH4-N, trichloramine NCl3 is the main chloramine component.
If the water’s chlorine content falls below the ratio of 2 to 4 mg per mg of NH4-N, especially oxygen dissolved in the water is consumed for the oxidation of ammonium by micro-organisms. The oxygen is used up rapidly. As a consequence, partial denitrification of the water starts. This can lead to the production of highly toxic nitrite (NO2-). The process of denitrification due to the
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oxidation of ammonium is a multiple-stage micro-biological process. Denitrification, which is incomplete and only proceeds as far as the nitrite stage, is described by the following chemical equation:
NH4+ + 2 NO3- => N2 + NO2- + 2 H2O
Ammonium Nitrate Nitrogen Nitrite Water
If the chlorine surplus is excessive, i.e. a chlorine/nitrogen ratio of more than 6, greater problems of smell can be expected /2/. Modern water treatment therefore requires that all the ammonium must have been transformed into nitrate before the addition of chlorine.
So much for theory. In contrast to this, the treatment of swimming pool water has to deal with small amounts of ammonium and urea which are continuously deposited in the water by the people. The elimination of all ammonium nitrogen before chlorine is added is therefore practically impossible. In this case, the formation of chloramines can only be reduced by means of an effective elimination strategy such as the UV radiation method described below.
4. Degradation of chloramines through UV radiation
The exact mechanism involved in the transformation of chloramines when they are exposed to UV light has not yet been fully explained. The most important degradation processes discussed in the literature are described in the following sections of this article. The complex processes during the chemical degradation of nitrogen chloride have already been described in detail by G.C. White in the “Handbook of Chlorination” (1980) /6/.
4.1 Breakdown of monochloramine due to the effect of UV light according to /1/
4 NH2Cl + 8 H2O + h x  􀃙 4 Cl- + 5 H3O+ + NO3- + 3 NH3 (1)
UV radiation enables splitting of a covalent chlorine-chlorine CI-CI compound or a nitrogen chloride CI-NHR compound (R= organic residue e.g. of type CnH2n+1).
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Breakdown occurs due to excitation of the Cl – Cl and Cl – N bonds by means of the electromagnetic wave spectrum in the UV-C range. In the process, electrons are raised to an antibonding orbital. The molecule is destabilized and finally breaks down /1/. The products of chloramine degradation which is initiated by UV light are chloride, nitrate and ammonia. Degradation is accompanied by a reduction of the pH value. The ammonia thus released, however, reacts to form chloramines again if more chlorine is added.
4.2 Monochloramine, dichloramine and trichloramine degradation according to /3/
Monochloramine
Monochloramine is split at a wavelength of  = 245 nm and is oxidized to form elemental nitrogen when it comes into contact with free hypochloric acid. Small amounts of hydrochloric acid are also produced in this reaction:
2 NH2Cl + HClO 􀃙 N2 + 3 HCl + H2O = 245 nm (2)
The production of acid is expressed by a barely measurable reduction in the pH value.
Dichloramine
After catalyzation due to UV radiation, dichloramine is initially hydrolyzed to become a dichloro-nitrogen anion.
NHCl2 + OH- 􀃙 NCl2- + H2O (3)
The dichloro-nitrogen anion immediately reacts with dichloramine to produce a multiply chlorinated hydrazine compound, namely trichloro-hydrazine Cl2N-NHCl:
NCl2- + NHCl2 􀃙 Cl2N-NHCl + Cl- (4)
Via a further intermediate stage, whereby hydrochloric acid is split off, the trichloro-hydrazine reacts with the N = N double bond, namely dichloramine N2Cl2,
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to form elemental nitrogen, which degasses, as well as chlorine gas and hydrochloric acid. The chlorine thus released is then available in the swimming pool water for purposes of chlorination:
Cl2N-NHCl 􀃙 Cl-N=N-Cl + HCl 􀃙 N2 + Cl2 + HCl  = 297 nm (5)
The entire reaction, made up of stages (3), (4) and (5), is a UV-catalyzed transformation of dichloramine in the presence of hydroxide ions to form elemental nitrogen, hypochloric acid, water, chloride and protons. As a result of this series of reactions, acid capacity is used up:
2 NHCl2 + OH- + H2O 􀃙 N2 + H2O + Cl2 + 2 Cl- + H3O+ (6a)
N2 + H2O + Cl2 + 2 Cl- + H3O+ 􀃙 N2 + HClO + HCl + 2 Cl- + H3O+ (6b)
Or (6a) and (6b) summarized:
2 NHCl2 + OH- + 2 H2O + h x  􀃙 N2 + HClO + 3 Cl- + 2 H3O+ (6c)
Trichloramine
Compared to monochloramine and dichloramine, trichloramine only plays a subordinate role in terms of quantity in the context of swimming pool water treatment. However, trichloramine has a very strong smell and causes greater irritation of human tissue than monochloramine and dichloramine even if it is only present in much smaller concentrations. The transformation of trichloramine when it is subjected to UV radiation in the UV-B range is shown by the following equations:
2 NCl3 + 6 OH- 􀃙 N2 + 3 ClO- + 3 Cl- + 3 H2O  = 340 nm (7)
4 NCl3 + 6 H2O 􀃙 2 N2 + 12 H+ + 12 Cl- + 3 O2  = 260, 340 nm (8)
Equation (7) shows that the reaction takes place when there are increased pH values and a surplus of hydroxide. Equation (8) describes the degradation of
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trichloramine when subjected to UV radiation, starting from a neutral milieu with the formation of protons.
Reactions (2), (5), (7) and (8) which take place or are induced during exposure to different UV wavelengths explain why the reduction of mucous-tissue inflammation in swimming pool water due to the effect of polychromatic light from medium-pressure lamps is much more effective than if low-pressure lamps which emit monochromatic light are used.
Fig. 9: The polychromatic spectrum from medium-pressure UV lamps and the photochemical degradation of chloramines
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Spectral data of low-pressure lamps
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Fig. 10 The monochromatic spectrum of low-pressure UV lamps in the UV range
The transformation of chemical substances takes place according to the laws of physics. The first photochemical law according to Grotthuss-Draper is:
A photochemical reaction can only take place if a certain energy quantum, characterized by its wavelength, has been absorbed by the molecule to be transformed.
Every low-pressure mercury UV lamp has an emission line with a maximum intensity of 253.7 nm. This absorption line has a certain width and encompasses lower and higher wavelengths to a small extent. The wavelength of 245 nm, which is needed for the photochemical degradation of monochloramine in accordance with (2), is provided to a small extent by the spectrum of a low-pressure lamp. If, however, there is more dichloramine and trichloramine in the water, low-pressure lamps cease to have an effect. The spectrum of medium-pressure lamps has a sufficient intensity at 260 nm and 340 nm for trichloramine degradation and, especially at 297 nm, for dichloramine degradation. Only medium-pressure lamps are therefore effective in degrading chloramines and especially in eliminating dichloramine and trichloramine.
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((Proposal for additional text))
Investigations in the Langnau indoor swimming baths on the Albis, Switzerland
The Langnau indoor swimming baths on the Albis in the canton of Zürich consist of a pool for swimmers and a pool for non-swimmers. The total volume amounts to around 700 m3. The water for both pools circulates through a diatomite filter and is disinfected with sodium hypochlorite (type llB in accordance with SIA 385/1). On peak days, high concentrations of bound chlorine occurred repeatedly, sometimes close to the tolerance value of 0.3 mg/l. The addition of powdered active carbon was able to reduce these levels somewhat but not eliminate them entirely. Filter backwashing and re-flooding did not lead to the desired result either. An improvement was only achieved by adding much more freshwater. In 2004, a UV disinfection system with two 2000-watt medium-pressure lamps was therefore installed in the Langnau indoor swimming baths as an alternative to active carbon. The UV test system was installed in the full current directly after the circulating pumps and before the flow was split up between the pool for swimmers and the pool for non-swimmers. Because the swimming pool water passes through the filter before being radiated, cloudiness is minimized and maximum radiation intensity is therefore achieved.
In an long-term test over a period of around four months, the UV system was operated at different intensity levels and with different amounts of fresh water being added. This was done during the entire day or only during opening times. The concentrations of free and bound chlorine were measured and evaluated in both pools several times a day. These data were supplemented with manual urea measurements in the filter.
The aim of this test was to measure how much chloramine the UV system was able to degrade and how much this enabled a reduction in the amount of material used such as fresh water, active carbon or chlorine. It was therefore possible to evaluate the effectiveness and economic efficiency of the UV system.
The measurement data clearly showed that, when the UV system was kept running for 24 hours a day, the chloramine concentration was reduced by approx. one third compared to the previous years. However, not only was the chloramine content
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reduced, it was also possible to reduce the consumption of fresh water by about 55 %. The amount of water used by each swimmer was around 70 liters a day during the test period. In the same period in previous years, this had been around 180 liters a day. For the lifeguards in Langnau, there were also some positive subjective changes from the very beginning. The typical smell of an indoor swimming pool has been greatly reduced, the water is clearer, the cloudiness in the pool is less than without the UV system and the number of complaints due to “bad water” has decreased considerably. The UV system has therefore been kept in use even after the test period. /9/
Installation of UV systems
A UV system is always installed directly in the main flow of water, after the filter and before the disinfection stage. This protects the UV system against particles of dirt, hair, etc. Due to the minimal cloudiness of the water at this point, maximum radiation intensity is achieved. It is also advantageous if the UV systems are fitted with a built-in cleaning mechanism. Thanks to this manual or automatic cleaning mechanism, there is no need for chemical cleaning equipment and its installation in the network of pipes. Moreover, the system does not have to be shut down during the cleaning cycles.
If the UV system is installed directly after the filter, direct protection against legionella bacilli is also provided. The destruction rate is up to 99.99 % depending on the intensity of radiation. The positive effect of the UV system is especially apparent in hot bubbling pools, therapy pools and exercise pools, the reason being that, in these cases, the contamination of the water and filters used is especially high due to the high water temperatures. Legionella bacilli prefer to settle in the filter bed. This especially affects filters with active carbon loading. Even chlorination during filter backwashing does not eliminate the legionella bacilli. A UV system with a wide spectrum thus has a double effect: it degrades bound chlorine and disinfects the water. This pays for itself.
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E-mail: roland.hensel@siemens.com
Literature
/1/ Chen, Gobulukoglu: The Elimination of Residual Chlorine / Chloramine in Water using UV Radiation
/2/ Draft Guidelines for Drinking Water Quality Management for New Zealand, October 2005 http://www.moh.govt.nz/moh.nsf/0/ 5A25BF765B400911CC25708F0002B5A8/$File/15-disinfectionprocesses.DOC
/3/ Zinnbauer 1988: Persönliche Mitteilung an Mr. Brannon, Mr. Wilder, Coca Cola USA, July 13th 1988
/4/ Roeske W. 1980: Schwimmbeckenwasser
/5/ G. C. White (1980): Handbook of Chlorination, 2nd Edition, Van Nostrand Reinhold
/6/ Stottmeister; Voigt (2006): Trichloramin in der Hallenbadluft, Archiv des Badewesens 158 – 162, 03 (2006)
/7/ Hollemann, Wiberg (2007): Lehrbuch der Anorganischen Chemie 102. Auflage
/8/ Povl Kaas, Hendrik R. Andersen (2007): Photochemical and Advanced Redox Treatment of Pool Water, Presentation given on the 2nd International Pool & Spa Conference 2007 Munic
/9/ UV-Anlagen zur Chloraminreduktion – Ein Praxisversuch im Hallenbad Langnau am Albis Veröffentlicht in: VHF/GSK-Bulletin 1/2005
15 / 16
Siemens AG
Corporate Communications
Media Relations
D-80312 Munich
Reference number: I&S 1007.6720e
Press Office Industrial Solutions and Services
Roland Hensel
P.O. Box 3240, D-91050 Erlangen
Tel.: +49-9131 7-44432; Fax: -25074
E-mail: roland.hensel@siemens.com
Equipment used by Wallace & Tiernan for chloramine reduction
Photo 1 Barrier M
Photo 2 DEPOLOX pool
Photo 3 The total chlorine measuring cell determines the amount of bound chlorine and thus reduces the circulating volume rate of flow (see Wallace & Tiernan-publication for EWO Pool Energy and water optimization concept)
Further information at: http://www.siemens.com/wallace-tiernan
Bitte senden Sie Druckfahnen, Korrektur- und Belegexemplar an:
Siemens AG, Industrial Solutions and Services Group Communications – Pressereferat (I&S GC MR) Roland Hensel Schuhstraße 60, 91052 Erlangen Tel. 091931-744432, Fax -725074 E-Mail: roland.hensel@siemens.com 16 / 16
Siemens AG
Corporate Communications
Media Relations
D-80312 Munich
Reference number: I&S 1007.6720e
Press Office Industrial Solutions and Services
Roland Hensel
P.O. Box 3240, D-91050 Erlangen
Tel.: +49-9131 7-44432; Fax: -25074
E-mail: roland.hensel@siemens.com

EPA Document for Guidelines

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