Every disinfection system has ...

Every disinfection system has its drawbacks and you have to decide on what works best for your intake water. Ozone is great, but could lead to bromate violations if you have bromide (if you are required to monitor for bromate). UV is great if you control your turbidity since bacteria can hide in particles. Chlorine is an excellent traditional one, but forms DBPs that you may have to monitor depending on where you are. Disinfection in general will be easier with some sort of pretreatment to reduce the load of organics that can create a demand for disinfectants or affect UV efficacy. A good approach will be to identify the regulations applicable to your area and decide on the best affordable technology.