Anaerobic digestion of poultry mortalities

• Main Authors: Shyu, Wuu-Huann, 徐武煥
• Other Authors: Ten-hong Chen
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/23613722306614529063

碩士 === 國立中興大學 === 農業機械工程學系 === 84 === ABSTRACTThis research studied anaerobic digestion of poultry mortalities in a sequential batch system. Chicken purchased from a local market were used. The chickens were divided into four components for the leachbed (LB) where they underwent hydrolysis/acidogenesis. Leachate from the LB was pumped to the methane reactor where organics in the leachate were converted into harmless end products like methane and carbon dioxide.The sequential batch system consisted of a hydrolysis/ acidogenesis reactor and a methanogenesis reactor. A leachbed served as the hydrolysis/acidogenesis tank while an upflow anaerobic sludge blanket (UASB) served as the methanogenesis tank. The two reactors were connected to form a closed-loop.For each batch of chicken, the system initially performed like a two-phase system. As operation continued, due to repeated inoculation of the LBs bythe UASB, the LBs gradually became a single-phase system.This research studied the operating and treatment characteristics of the LB-UASB system operated under different temperatures (55 and 35 C) and with different amount of water (3 and 10 L) added to the LBs.The results indicated that the UASBs adapted well to feed interruption, hence, is suitable for treating organic waste materials with unsteady supply, such as chicken mortalities. The rate of hydrolysis/ acidogenesis was faster at 55 C than at 35 C. In addition, when 10 L instead of 3L of water was added to the LB, the extent of hydrolysis/acidogenesis was greater. Because bones in carcass contained inorganic ingredient, its weight reduction was less than that of offal. Bones remained when digestion was completed. This residual material need to be disposed of by other methods. Feather was degraded to a significant extent, the highest reaching 91.3% reduction. More feather was reduced at 55 C than at 35 C. There might be feather-degrading microorganisms in the LBs. Therefore, treatment of feather by anaerobic digestion should not be a problem.In the LB-UASB system, acid concentrations in the LB affected methane production from the UASB. When acid concentration was too high, methanogenesis was inhibited. More liquid in the LB lowered acid concentration, and was beneficial to methane production. In all four experiments conducted, acid concentration in the UASBs were higher than 1 g/L, thus, significant inhibition to methane production was implied.