a.) Don’t use pesticide or antibiotic as fermenting material.

b.) Don’t use nippy things, such as scallion, garlic, pepper, mooli, curare and its stalks and leaves, and manure produced by livestock after eating them as fermenting material.

c.) Heavy metal compounds are not allowed to be put into the biogas reactor.

d.) Using only straws as fermenting material will hardly produce biogas, due to they contains little nitrogen. Things rich in nitrogen should be mixed with them.

e.) Things like bone flour rich in phosphor are prohibited.

f.) If straws and grasses added are too much, reasonable amount of plant ash/lime water and such inoculum as sludge, fermenting manure should be added, in case that the fermenting material acidifies.

g.) Don’t add too much alkaline things, in case that the fermenting material is alkali-poisoned.

h.) Don’t add too much things rich in nitrogen, in case that the fermenting material is ammonia-poisoned.

i.) Straws or grasses should be cut into pieces, in case that the biogas digester is blocked.