Our old well is shallow, so it is inevitable that some form of bacterial contamination will get into the well water. We use injected chlorine to oxidize the ferric iron present in the water so that the sand filter can catch it and remove it.
We also use a DWS-7 Ultra Violet (UV) disinfection unit made by ATS to be sure that the water does not contain any harmful bacteria. The UV kills any bacteria that are in the water. The DWS-7 has a maximum effective flow rate of 7 gallons per minute.
The UV unit was installed before our closing because the house did not pass its water test. The installation looks pretty good with appropriate shut off and bypass valves, unions to remove the unit and a boiler drain.
Basically, the UV light itself looks like a small florescent tube with an electronic ballast. The light slides into a glass tube within a metal cylinder. Water enters one end of the cylinder and flows to the other end, thus being exposed to UV light for a period of time. Exposure to UV kills any bacteria in the water.
The light bulb lasts about 1 year, and they are about $85-95 dollars each to replace. You can check the operation of the light bulb by viewing the small port on the side of the unit. It is recommended that you do not look directly at the viewing port as UV can damage eyes. Put your hand up to the port and look for the green glow on your fingers.
To replace the light tube, remove the brass covers on the top and bottom. There is a wire which runs to each end of the tube and are held in place by clips. Remove the clips and slide the light tube out. Slide the new tube in.
The manufacture also recommends that you clean the glass tube every year or so. For this you have to dismount the unit from the wall and take it apart. Clean the glass with a mild dish detergent and rinse.
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