Disinfection apparatus having submersible disinfection devices for disinfecting fluid. The disinfection apparatus includes: a pipe having one or more linear segments； one or more disinfection devices installed on the pipe, each of the one or more disinfection devices generating light for disinfecting fluid in a linear segment of the pipe； and a controller electrically coupled to the one or more disinfection devices and controlling the one or more disinfection devices. Another embodiment of the disinfecting apparatus includes； side and bottom walls and a lid that define an enclosed chamber； an inlet and outlet for communicating fluid to the enclosed chamber； a plurality of disinfection devices disposed on the side wall, each of the plurality of disinfection devices generating light for disinfecting fluid inside the enclosed chamber； and a controller electrically coupled to the plurality of disinfection devices and controlling the plurality of disinfection devices.
