Which of the following is a method to disinfect well water?

Ultraviolet (UV) light is an effective method for disinfecting well water because it utilizes specific wavelengths of light to kill or inactivate microorganisms such as bacteria, viruses, and protozoa. When water is exposed to UV light, the DNA of these pathogens is altered, rendering them incapable of reproduction and causing illness. This method is particularly advantageous because it does not introduce any chemicals into the water, making it a safe and environmentally friendly disinfection option.

Other methods listed, such as water softeners, reverse osmosis, and distillers, primarily focus on the removal of minerals, contaminants, or impurities rather than disinfection. Water softeners reduce hardness caused by minerals but do not eliminate pathogens. Reverse osmosis is effective for removing a variety of contaminants, including some pathogens, through a filtration process, but it does not specifically target microorganisms like UV light does. Distillers also purify water by boiling it and collecting the steam, effectively removing many contaminants, but they may not be as effective as UV light at inactivating pathogens. Thus, UV light stands out as the method specifically designed for disinfection in the context of well water.