I’ve been bokashi composting, worm farming, tumble composting, hot and regular composting for the best part of 30 years with wonderful success but have never had a soil factory. At first I had a garden where I could dig the bokashi into the ground but since I moved to Devon that proved near impossible with the heavy, sticky red clay soil we have here. I could literally make pots out of the stuff! I started adding the bokashi to my worm farm but though the worms did eventually eat it many also migrated as I assume it was too acidic despite all the added extras I added to keep them happy. I then started adding the bokashi directly to my compost bin and that works great, so great in fact that it’s so full of worms it’s difficult to get soil out without the worms coming too. Because of this I’ve stopped using a separate worm farm and just throw everything in my compost bins. From the other questions I’ve read it seems your using soil factories but is that not just a small scale compost bin of sorts? Is it really necessary? On another subject I also bokashi my dogs poop which then gets tumbled for several weeks in my Envirocycle in full sunlight to build up heat. Once that process has been done it goes into my general compost bin which remains steamy even in the winter. The worms devour it and I’m left with sweet smelling compost. I was worried as I worm my dog monthly that this wouldn’t work but I assume the bokashi breaks it down sufficiently not to affect the worms. I have been experimenting with another way of composting dog poop recently. Once a year I have a bonfire with branches and other things I’ve cut back in the garden. My incinerator gets added to throughout the year and I started adding the poop too. The ash then gets added to my general compost bin and I know that the poop is completely void of any nasties.
Yes a soil factory is kind of like a compost bin, but perhaps its better to describe it as mimicking a garden on a very small scale. You are simply bringing in healthy garden soil, so that it can process the bokashi fermented food waste into the soil structure. The people who use this method are ones who do not have access to a garden. If you have access to a garden, then its better and easier to take your bokashi fermented food waste directly there.