6. 7. T Is UV disinfection more likely to be used by drinking water utilities that use groundwater or surface water sources? Explain your answer. Hint: are viruses, protozoa, or bacteria more of a concern with groundwater or surface water? 8. L Treatment facilities have multiple ion exchange resin present in series. Why? A desert community pumps groundwater from an aquifer that contains a hazardous amount of arsenic. The community has no alternative water sources. List at least two advantages and disadvantages of using reverse osmosis for this application relative to ion exchange.