RESULTS AND DISCUSSION
The aim of this study was to evaluate the feasibility of biogas
production from chicken manure in a mesophilic acidogenic
ethermophilic methanogenic two stage anaerobic system under
different OLRs. Hydrolysis and aceticlastic methanogenesis are
often considered as the rate limiting steps for the anaerobic
digestion of organic solids. Limiting step changes due to substrate
type, OLR, HRT and temperature of the process (25,26). By using
two stage system it is possible to reduce the HRT and reactor volumes,
and increase the volatile solid (VS) loading rate, improve the
VS destruction efficiency, reduce the inhibition effect of TAN and
therefore, enhance the methane production and improve the process
stability. Operation of the methane reactor at thermophilic
condition can further improve the reaction rate and lower the HRT.
Therefore in this study, unlike most of the two stage reactor configurations
(thermophilic acidogenicemesophilic methanogenic),