How does the heavy rains in 1986 relate to the increased incidence of waterborne disease from private water systems? Years with heavy rains caused the septic tank water to mix with the rain and entered the reservoir. Years of heavy rain caused the reservoir water to mix with the rain and entered the septic tanks. The floods caused the sewage lines to overflow into the reservoir. Years with heavy rains caused the septic tank water to mix with the private well water.

Waste water from industries and domestic sources can be treated by chlorination or ultraviolet radiation. there are pros and cons to using either chlorine or uv radiation to kill harmful microorganisms. what is one reason chlorination would be preferred over ultraviolet radiation? a) chlorine only eliminates visible impurities and is ineffective against microorganisms. b) chlorine not only kills bacteria but provides a residual effect on returning microorganisms. c) uv radiation can be used only to treat drinking water and is ineffective in treating waste water. d) ultraviolet radiation is more effective