One of the most common queries we get this time of year is people wanting to filter or treat dirty rainwater. Now we are at the end of summer, rainwater tanks are at their lowest level for the year. When the new season rains start, then these inflows cause the water to be stirred up, making water look dirty, taste bad and in some cases be dangerous to your family’s health. With any rainwater tank installation for use on a house, we always recommend that you install cartridge filtration as a bare minimum to ensure the water stays clean and safe. In addition to this, we recommend that you utilise a form of disinfection to kill any remaining microbes before they enter your house plumbing and drinking water. Probably the most common type of disinfection for domestic water is Ultraviolet (UV) filtration, it is also used widely by local councils, the food, dairy and brewing industries.
Once water is filtered to 1-5 micron, then it is passed through a housing which exposes the water to a UV light source. This renders any remaining microbes that are in the water sterile and stops them from multiplying. This minute number of microbes die after a short period and with no growth of microbe populations, the water is disinfected. There are many different brands and models of UV filtration systems available, one of the most renowned and what we recommend and sell is the Davey Steriflo. These sturdy and reliable units have been made by Davey in both New Zealand and Australia for around 20 years. There are units in the range from 15L under sink and 40l-150L whole house right up to commercial units that treat 4500L/min.
The unit for your house consists of a stainless steel canister, which has a waterproof quartz glass tube inside it. A florescent UV globe is fitted inside the tube and this is controlled from a ballast power source which plugs into a 240V power point. When filtered water passed through the canister, the UV light attacks any microbes that were not removed with filtration and disinfects the water. The water needs to be filtered so that there are no particles remaining that will shadow the UV light and stop it working.
As with any treatment system, there is some basic maintenance that needs to be done to keep it operating to its maximum capacity and keeps your water safe. The main things to check are:
- Your filters, usually a 20 or 50 micron course and a 1 or 5 micron fine or carbon cartridge, need to be changed out approximately every 6 months. This stops them blocking up and stopping water flow, but also stops them filling with microbes that then grow and will finally work their way through your system.
- Your thimble and globe. Once every 3 months, the UV unit should be checked. This involves cleaning the outside of the quartz thimble so that light can get through it and keep on functioning to capacity. In addition the globe should be checked to ensure it is working.
- Your Globe. Even though it may still work, the globe should be changed approximately every 18 months to 2 years. After this much operation time, the globe stops producing large amounts of UV light and will not be effective in killing microbes any more.
At Southern’s we can supply, install and service your filtration equipment. If you want to buy the parts and DIY we will help you with fitting and selecting the correct parts.
If you want it regularly serviced, then our helpful staff can book you in for routine maintenance, remind you when it’s due and get the work done quickly and professionally to give you complete peace of mind.
UV Filter Board