Evaluation of an anaerobic system for treating poultry mortalities

A closed-loop anaerobic system was evaluated as an alternative for poultry mortality disposal. The bench-scale system consisted of an upflow anaerobic sludge blanket (UASB) and three leachbeds (LB). The UASB served as the methanogenic phase of the system. The LBs were batch-loaded with dead chickens and initially served as the hydrolysis/acidification reactors. When digestion in a LB was complete, the fermentation fluid in it was reused to start up the next LB. The system satisfactorily completed treatment of seven batches of mortalities in 432 days. The average CH4 yield was 0.254 m(3) (kg wet weight)(-1). More flexibility in scheduling may be desirable by including an additional LB. Additionally, a fifth LB would simplify restarting of a LB from as preceding LB being terminated. Cost estimates based on systems with one UASB and five LBs ranged from NT$4.24 (kg live wt)(-1) for a 10,000 birds poultry farm to NT$1.13 (kg live wt)(-1) for a farm with 100,000 chickens.