A portable, personal advanced-oxidation water treatment system based on ozone and a catalyst such as titanium dioxide that can cycle and purify water to make it portable by removing organic contaminants. The unit can be used for long periods of time without having to replenish the active portions. The unit can be carried in a backpack or in a vehicle. Fresh water is typically loaded into the unit, and the unit is cycled until the water is pure enough to drink. A battery is used to produce ozone and to cycle the water through a reaction vessel and can optionally be charged with a small solar panel The unit can also be powered directly from a vehicle.