Generally most systems come with a 2 or 3 filter configuration and have a UV chamber attached on the side or top of the unit.
Simple explanation of how 'UV water filter systems' work
Firstly the Filtration Process. The right system for you may have either 1,2,3 or 4 filters. The purpose of the filtration is two fold - to improve the quality of your water - & to improve the clarity of the water so that the UV light can effectively sterilise the 'living nasties'. Cartridges trap contaminents either on the 'surface' of the filter material or within the 'depth' of the filter material.
- Primary Filter - Can be a course (50 or 20 micron) cartridge to cope with large amounts of floating material such as leaf fragments and courser particles of mud/silt. Can be a fine 1 micron if the water is exceptionally clean. Typically a 5 micron to cope with most water sources. The first cartridge is typically a 'pleated paper' surface cartridge, but may also be a synthetic depth cartridge. A surface cartridge is washable if you have the time, but certain material such as pollen can remain lodged in the papers pores.
- The second filter (on a 3 filter system) usually contains a carbon block cartridge which primarily improves taste & removes odor. The carbon can also help with removing most sprays. These carbon cartridges are a larger version of what many households have under their sinks.
- The final filter contains a Melt Blown Polyprop 1 Micron depth cartridge (a little like a condensed toilet roll). This is the polishing filter which removes fine sediments .
All cartridges 'plug' progressively as material becomes trapped, to the point where your shower pressure reduces enough to cause you to change the cartridges. Some users prefer to locate a fine 1 micron sacrificial cartridge prior to the carbon cartridge to extend its life, as fine particles can coat the carbon thereby rendering 'activation' as ineffective.
Secondly the Sterilisation Process.
- The filtered water is now sufficiently clear (the correct turbidity)as it enters the UV chamber.
- The chamber is fitted with a quartz sleeve (seals at both ends).
- A UV lamp sits inside the sleeve. This is a dry area (provided the sleeve is not cracked).
- The wattage of the lamp needs to be sufficient to sterilise at the maximum water flow rate that your building will experience.
- The water spirals around the chamber whilst being exposed to the UV light (the sleeve must be clean) which sterilizes the reproductive organs of the 'living nasties'.
- These 'bugs' will not be able to multiply, thereby rendering them harmless and the water safe to drink.
In summary the right system for you will comprise two essential matches:
- the right balance of cartridges with your water source
- the right lamp wattage for your water usage