Enhanced biogas production and performance assessment of a full-scale anaerobic digester with acid phase digestion
Acid phase digestion pretreatment resulted in an increase in biogas production and volatile solids (VS) removal at the West Camden plant which was fed with only waste activated sludge. Without the acid phase digesters, the specific methane yield of waste activated sludge (WAS) was 190 L/kgVSadded, whereas a specific methane yield of WAS of 231 L/kg VSadded was observed from sludge sampled from the acid phase digester. The specific methane yield obtained from BioWin® simulation was 331 L/kgVSadded and was slightly higher than that from BMP assessment (231 L/kgVSadded). In addition, the overall VS removal values obtained from BioWin® simulation (44%) and biomethane potential (BMP) evaluation (49%) were close to the actual VS removal value (45%) achieved by the plant. The consistency between full scale evaluation data, BioWin® simulation, and BMP assessment suggests that BioWin® simulation and BMP study can be used to guide future design and optimisation of acid phase digestion pretreatment to intensify anaerobic digestion of sewage sludge.