Abstract: A purification apparatus comprising a filtration unit comprising filtration screens, a disinfection unit comprising a source of disinfecting light and a passage for filtrate from the filtration unit to the disinfection unit. The filtration unit may be selected from at least one static drum, at least one rotating drum, and at least one filter pack. Louver vanes or baffles may be used in the passage to create turbulence and direct flow. A process for removing particulate matter and disinfecting a process flow comprises the steps of filtering the process flow to remove particulate matter, directing the filtrate to a source of disinfection light while creating turbulence in the filtrate and disinfecting the filtrate.