Effect of two-added powdered bamboo-charcoal on sludge granulation of UASB reactor

Aimed to investigate the effects of the difference in the addition of powdered Bamboo-Charcoal on the sludge granulation in upflow anaerobic sludge bed (UASB), two UASB reactors were used to treat piggery wastewater, the sludge granulation and characteristics of granluar sludge were evaluated between the testing group UASB reactor (with two-added powdered Bamboo-Charcoal) and the blank group UASB reactor (with one-added powdered Bamboo-Charcoal). The results showed that the addtion of powdered bamboo-charcoal could markedly accelerate the anaerobic granulation and facilitate the formation of the large-size granluar sludge after producing the granluar sludge. It could improve the settlement ability of granluar sludge and accordingly increase the COD removal efficiency. On the 57st day, the sludge granulation rate (SGR) from sludges on the bottom and the top of the testing group UASB reactor reached 94.5% and 60.7% respectively, higher than the blank group by 7.9% and 17.3% respectively; The content of granluar sludge (Diameter＞1.7 mm) of the bottom for the testing group reactor reached 41.7%, while the blank group only 32.4%; The COD removal rates of the testing group and the blank group reached 81.6% and 75.7% respectively. Based on the results of the experiment, the second addition of Bamboo-Charcoal following the apperance of granluar sludge exhibited the ability to enhance sludge granulation process dring start-up.