| Summary: | 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.
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