I don't know the case of mushroom cultivation with sludge in direct use.
But, Li commented that the ratio between Straw and stalks:dregs = 1:10.
I suppose that the sludge contains very little carbon source and could
be a source of microorganisms for fermentation or composting.
Therefore, the ratio between straw and dregs is quite strange.
That must be 10:1 or at least larger in straw and stalks than dregs.

The available information on mushroom cultivation is very little.  I would like to know the following information.
(a) What kind of compounds are included in dregs?
(b) What kind of microorganisms are working in composting process?
(c) What kind of chemical components are produced by composting?
(d) What kind of mushroom species are produced?
(e) How is the productivity of mushrooms?

With best regards,

Koji
++
Dr. Koji Iwase
Biological Environment Institute
Uji, Kyoto, Japan