I have a grey water drain (70mm diameter) that has roots growing in it. I can rod the first foot, and that's it. Looking for some chemical that will work to clear them, as physical removal is nigh on impossible. The pipework leads to a septic tank, where the bacteria live on all the sewerage that arrives in a different tube, so anything which kills them isn't such a good idea.
Hoping there's a chemical which will dissolve the roots, but still be kind to the bacteria. Digging up the pipe isn't easy - concrete has been put over the ground above it.