Codigestion of Taihu blue algae with swine manure for biogas production

Anaerobic digestion (AD) of Taihu blue algae and its codigestion with swine manure was evaluated at different inoculum substrate ratios (ISRs) from 0.5 to 3.0. Results showed that codigestion of blue algae with swine manure led to the highest methane (CH4) production of 212.7 mL g−1 VS at ISR 2.0, while digestion of blue algae inoculated with granular sludge brought out the optimized CH4 production of 73.5 mL g−1 VS at ISR 3.0. The values of pH, total ammonia nitrogen (TAN), free ammonia nitrogen (N-NH3) and volatile fatty acids (VFAs) showed no significant difference between the digestion and codigestion, confirming the appropriate stability of the two batch anaerobic processes. Closer examination of VS removal rates and key enzymes variation proved codigestion had higher efficiencies in biodegradation and methanation, which demonstrated that AD of blue algae with swine manure was a promising technology for both solid wastes treatment and renewable-energy production.