Comfrey plants multi uses

I attended a farm walk with Alan Keys and the Ballinderry Rivers Trust a while back to look at a dirty water swale system. What got my attention was the comfrey plant. Alan advised I buy a book by Lawrence Hills, he is the guru on comfrey.

This powerful plant can utilise up to 2.5L of water a day. It has impressive medicinal uses, great protein and B12 for animal fodder and will ferment to make a potent fertiliser.

After looking around I did find many companies selling it as a liquid

plant food and as dried leaves for medicinal use. The root is divided to make more plants as it does not provide seed.

I am looking at planting around 500 on a stretch over an extra underground drain to take all yard water and roof run off to the main drain to the river. The comfrey will clean the water and it is a long stretch to the river.

I plan to then harvest the plant to ferment for a fertiliser for the farm.

Has anyone done this or know of anyone doing it?

I'd love to chat with them and get some advice.