Photo: R. Hemmingsen
UV lys ødelægger DNA i de enkle celler så mikroorganismer ikke kan formere sig igen.
UV lys er stabil, nem, økonomisk og miljøvenlig at bruge.
Der er ikke nogle mikroorganismer som kan tåle UV lys, for at ødelægge DNA i celler må man vide hvor meget UV lys (mWs / cm2) de enkle celler kræver.
For at kunne give den rette mængde UV lys for at ødelægge DNA i mikroorganismer, er det vigtigt at vide UV lyset lysgennemtrængelighed og UV lyset lysabsorbering, i det vand der skal UV-bestråles. Samt hastighed af det vand som skal UV-bestråles.
Lav vandhastighed giver en kraftig bestråling (mWs / cm2)
Høj vandhastighed giver en mindre bestråling (mWs / cm2)
Low pressure lamps mainly emit radiation with a wave- length of 253.7 nm, which is appropriate for the bacteria treatment of air and water. They are typically used for sterilisering drinking water, upgrading grey water in industrial settings, and reducing bacteria and vira in fish farms. They are also employed in air conditioning and cooling systems and will disinfect surfaces as well as air.
Generally, UV is installed simply, requires low maintenance, or space. Also low operation and maintenance costs, and no chemical smell or taste in finished water are all factors favoring UV technology to many other traditional disinfection technologies.
Ultraviolet or UV energy is found in the electromagnetic spectrum between visible light and x-rays and can best be described as invisible radiation.
UV energy penetrates the outer cell membrane, passes through the cell body, and disrupts its DNA, preventing reproduction.
UV treatment does not affect the water chemically; nothing is being added except energy.
The sterilized microorganisms are not removed from the water and do not remove dissolved organics, or particles in the water.
The effect of ultraviolet radiation is directly related to the UV dose applied to the water. The dose is, a combination of UV light intensity and exposure time, and is measured in microwatt second per square centimeter (µws/cm2). Special low-pressure mercury vapor lamps produce ultraviolet radiation at 254 nm, the optimal wavelength for disinfection and ozone destruction. The Water ApS UV lamp never contacts the water as they are enclosed in a quartz glass from Water ApS
For Water ApS UV units to successfully disinfect water, the following parameters must be taken into account.
MediaCertaincontaminants in water can reduce the transmission of UV light through the water, which reduces the UV dose that reaches the bacteria. Suspended particles are a problem because microorganisms within particles are protected from the UV light and may unaffected by the UV-treatment.
Flow-rate Water ApS UV units have a maximum flow rate capacity. If the flow is too high, water will pass through without proper UV exposure. If the flow is too low, heat may build up which is damaging to UV lamps.
Advantages of using UV disinfection is: No known toxic or significant non-toxic by products.
Removes some organic contaminants No impact on the environment No danger of overdosing
No volatile organic compound emissions or toxic airemissions
Requires minimal space for equipment and reaction chamber
Does not affect minerals in water