Abstract
A pilot-scale (0.5 m3) anaerobic digester was constructed in a small Palestinian poultry farm. The farm, located in Beit Ur Al Foqa village of Ramallah district, with a total area of 140 m2 and accommodating about 1800 birds every 50 days produces annually about 6.57 tonnes (18 kg/day). The digester was filled with poultry manure and operated to obtain design parameters for a farm-scale biogas plant. The digester contained 20% of poultry manure co-digested with seed materials (70% cow manure and 10% anaerobic sludge) and mixed with the water in (1:1 ratio) to create dry digestion conditions (20% TS). Operated for one year, the feeding sequence of the anaerobic digester was once a day with a loading capacity of the daily produced manure in the farm. A low-cost solar water heating system was installed to enhance the biogas production in the digester under mesophilic process conditions. Poultry manure proved a suitable substrate for the installed biogas digester with total solids: 20%, and C:N ratio: 32:1. Total biogas production was 39.95 m3, and the methane content ranged between 46% and 68%. As substitute to natural gas, the biogas generated (788 MJ) was used for farm heating purposes during the study period. The fresh anaerobically digested slurry showed a nutrient rich fertilizer (NPK ratio of 2:3:3). Sun-drying of digested slurry increased pathogens removal (F. streptococcus) up to 3 log10. Anaerobic digestion of poultry manure constitutes a bio-resource for both energy and nutrients. It is therefore an environmentally sound technology with zero waste emissions.
Acknowledgment
The authors thank the Royal Scientific Society (Amman, Jordan) for the lab analysis for biogas composition.