Most of the rainwater harvesting systems rely on a combination of sediment filters, carbon filters and ultraviolet (UV) rays. All of these components work together to remove the impurities and ensure the water is potable. In order to understand elaborately how they work, we would take a detailed look at their functions.
A pair of sediment filters (25-micron and 5-micron respectively) removes the particulates from the water so that the UV light can do its job disabling the DNA of bacteria in the rainwater. Without these filters, the particles can block the UV light and the bacteria would be able to pass through it. Thus, it is important to change these filters on a regular basis. Moreover, UV light has the distinction of adding no harsh chemicals or flavour to the water, which makes it a preferred method to kill bacteria.
Carbon Filters :
Activated carbon filters are also used to treat the odour, test problems in water as well as remove harmful water contaminants. They are manufactured from a variety of materials such as coal and coconut shells.
In many installations, the sediment filters are followed by the carbon filters, which is then followed by the UV light. Some of the rainwater harvesting manufacturers in Kerry actually preconfigure these components for use in private wells and rainwater catchment systems.
Complications When The Water Treatment System Is Turned Off :
The placement of the carbon filter, between the sediment filters and the UV light, can be an issue in some isolated cases, specifically when the water system is not used often. In such cases, bacteria can adhere to the walls of the carbon filter and replicate, turning the carbon filter into a bacterial breeding ground.
This can also be a common case where the UV light is turned off to save energy. The water may become cloudy due to this explosion of bacteria. Even when the system is turned back on, this cloudiness in the water remains and can actually protect some of the bacteria to pass through the UV light. Furthermore, turning the UV light on and off may actually shorten its life.
What If You Want To Close For A Certain Period?
If you are opting for a vacation, shutting off the UV light is the only option. But you can certainly follow some simple solutions in this case:
Drain the filter and UV cartridges. Remove the canisters and store them in a clean environment before reinstalling the system. Or you can also opt to install new cartridges. Remember both options require sterilization of the cartridge with a bleach solution.
Position the carbon filter on the opposite side of the UV light and install a backflow preventer between the two. It ensures that only water treated by the UV light can flow into the carbon filter. From this method, the carbon filter will still be effective in removing taste and odour problems without forming a bacteria farm.
Add a little bleach to the system. To make the process effective, remove the carbon filter, turn off the UV light and make sure that proper dosage of bleach is used. Contact a rainwater harvesting company to apply the appropriate dosage.
UV light and activated carbon filters both play a key role, each of which has a specialised function to perform.