Comparative experiment of anaerobic granular sludge cultivation in two kinds of anaerobic reactors

Comparative experiments of anaerobic granular sludge cultivation in Internal Circulation(IC) and Upflow Anaerobic Sludge Bed(UASB) reactors were conducted on treating wastewater from pig farm. It is found that after 54 days cultivation large quantity of granular sludge formed in both reactors, but the diameter of granular sludge in IC reactor is generally larger than that in UASB, most granular sludge diameters vary from 1 to 4 mm in IC comparing 1 to 3 mm in UASB, 2～3 mm granular sludge in IC and 1～2 mm ones in UASB account for the most proportion, separately reaches 28.5% and 38.7%, at the same time granulars sludge with diameter larger than 5 mm were formed only in IC.