
Id have thought it possible to make something suitable.... but not just using a bucket with some holes in sunk into the ground.
You'd be looking at something more like an old fashioned sewage pit, different gradients of sand and gravel, with reeds etc to remove the different stuff out of the degrading effluent.
Possible in a LARGE garden and worth it perhaps if you have a lot of dogs, but if not, erm, not!
Em