Peroxide injection system
35% Food grade Peroxide is a good choice save for finding it from time to time, if you have a place that you can get it down the road it will work.
Like Chlorine it will need some form of contact time, chlorine is 20 minutes times the flow rate for the size of the tank, peroxide is less but a contact tank of some size would be a good idea.
There are say two ways of injection.
When the well comes on the injection pump comes on and injects
Then there is the flow injection, where water flow through a meter sends a pulse to the pump to inject based on the number of pulses.
Simplest is the well pump on and injection pump on, there a contact tank would be a good idea.
The injection based on flow would most likely get around that but would be more costly as that kind of pump and meter are not cheap.
There are formulas for pump stroke and % of peroxide in solution tank but it all comes down to a bit of trial and error because each well and location is different.