I get that approx 50kw, thats not a school project, something around 75amps at 440 3ph.
Looking at the link however that machine processes up to 2000litres an hour, I thnik the op probably wants to zap something the size of a can of pop.
Maybe soemthing like a zvs flyback driver circuit would work, powered from a largeish electrolytic and a thryristor, or a circuit that generates constant dc hv and on time varied by smoothing capacitance values in conjunction with a spark gap.
Be carefull rectifying and smoothing a flyback output, the fairly dangerous output becomes very dangerous when its used to charge up a capacitor.