It should be fine. I have a similar (non-Speidel) fermenter in 30 and in 60 liter. Some people argue that you should never ferment kombucha in plastic, because it might leach chemicals into the brew. If you do want to use plastic, then this (HDPE) is probably the best kind you can use. The nice thing about these fermenters is that they're relatively cheap, lightweight and come in BIG sizes. The only problem I see is that the hole might be a bit small for cleaning.
You'd have to leave the lid off, and cover with a cloth to get oxygen to the scoby. It'd be much cheaper to put a spigot on a food grade bucket, or use a bottling bucket.