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Nature Flow Systems use ultra-violet (UV) light as a disinfection medium.

Ultra Violet (UV) is nature's natural method of disinfection.  It is a specific section of wavelength that occurs naturally in sunlight.

Manufactured UV has a greater intensity than natural UV and is concentrated in the 254nm wavelength.  This wavelength will destroy or prevent the reproduction of micro-organisms through DNA disruption.  

How does UV affect an organism's DNA?

The mode of action by which bacteria, viruses, and molds are inactivated is well known and was established in the 1960’s. The primary mercury emission band occurs just below 254 nm. Fortuitously, genetic material is “damaged” by photons in the range from 230 to 290 nm. Optimum damage occurs near 254 nm. “Damage” is typically Intra-strand bonding across adjacent aromatic rings. A series of enzymes try to “fix” the lesion by excision and replacement. Inactivation occurs by 1) inability to fix the bond, or 2) a deletion of a nucleic acid or 3) replacing the wrong nucleic acid. This causes the organism to improperly reproduce.

 

How is UV Disinfection used in typical water and wastewater treatment systems?

UV sterilisation works by irradiating flowing water or wastewater with the correct dose of UV light. The design of almost all systems on the market revolves around a UV lamp, held in a quartz thimble, which is then placed inside a cylinder. Water or wastewater flows into the cylinder, around the outside of the quartz thimble where it is irradiated by UV light and passes out the other end. An identified weakness of UV disinfection is the gradual fouling of the thimble, which causes a decrease in UV light transmission through the water or wastewater. This decrease in light transmission means that the UV dose rate may not be sufficient to maintain effective treatment.

How does Nature Flow's technology overcome this weakness?

Nature Flow's self-cleaning UV technology basically provides a non-mechanical, self-cleaning device that ensures the thimble remains clear and thus maintain the correct UV dose rate for effective treatment.

Other companies have also tried to overcome this problem, however their methods rely on mechanical wiper or other devices made up of numerous moving parts. These methods may have some success in maintaining unimpeded UV light transmission however they require more maintenance, are higher in cost and have a greater risk of mechanical failure.

 

What are the advantages of UV disinfection compared with chlorine disinfection?

Chlorine

UV

(Nature Flow System)

Long retention time required (20-45 minutes).

Fast disinfection (3-5 seconds).

Corrosive.

Non-Corrosive.

Has a distinctive odour, can be tasted, and modifies pH, connected with the production of carcinogens.

Does not affect odour, taste, pH, chemical composition, and does not leave any harmful by-products.

High maintenance.

Low maintenance.

Expensive to run.

Generally cheaper to run than chlorine.

Sodium Hypochlorite degrades back into sodium chloride (salt) and therefore it becomes inactive on storage.

Lamps only need replacing when recommended hours have been reached.

Hazardous when transporting, storing, and handling.

No hazardous chemical.

 

What are the minimum quality requirements of source water?

For maximum UV germicidal efficiency source water (ie the water you wish to treat) needs to be relatively clear with minimal suspended solids.  

As UV treatment works by irradiating the waterborne pathogens it is most effective when it can pass unobstructed through these organisms.  Cloudy water in effect may "hide" these pathogens from the UV light and thus will reduce the germicidal efficiency of the UV treatment process.  

(Think of the suspended solids as a large number of small umbrellas with pathogens hiding under each one.  UV cannot effectively treat these pathogens as it cannot "see" them.)

Source water must meet these standards for effective UV treatment.

Turbidity

5 NTU

Suspended Solids

10 mg/litre

Colour

NONE

Iron

0.3 mg/litre

Manganese

0.05 mg/litre

pH

6.5-9.5

Hardness

6 gpg

Pre-filtration may be necessary to ensure source water complies with these concentrations.

 

Send mail to webmaster with questions or comments about this web site.  Copyright © 2015 Nature Flow Systems Pty Ltd atf Nature Flow Systems Trust.  Nature Flow Systems reserves the right to alter product designs and specifications without prior notification.  While every effort is made to ensure the information on this website is up-to-date, no responsibility is taken for incorrect or outdated information.  Last modified: 25-May-2015