Sepg. pig slurry into clean water and compost - using coagulant and flocculant to ppte. solids and centrifuge separator

摘要

Dung slurry from pigs, with a water content of 85-98% is treated by adding to the slurry a coagulant, pref. based on iron trichloride and aluminium sulphate, and a flocculant, pref. a cationic polyelectrolyte. The slurry is stirred and decanted so that it separates into a solid ppte. and water with a BOD 4,000 mg/l. The amt. of coagulant is pref. 0.1-4 g/l of slurry and the amt. of flocculant is 10-250 mg/l. The decanting is pref. mechanically assisted by means of a centrifuge. The water may then be passed to a biological treatment basin where the BOD is reduced to 100 mg/l. The solids may be processed to an organic compost for agricultural or horitultural use. The process enables pig slurry to be reduced to a useful solid prod., compost and clean water.