Improvement of Aquaculture Wastewater Co-Digestion Performance by Cattle Dung Using a Thermophilic Pilot Reactor and Fertiliser Recovery

The fundamental challenge to balancing the fuel demand is the risk of process instability. Research on energy recovery from aquaculture effluent addresses energy demands and environmental pollution concerns. The current study examined the effectiveness of anaerobic co-digestion of aquaculture effluent in a 45 L thermophilic reactor without utilising chemical catalysts. The partially digested cow manure created a substantial buffering capacity in this co-digestion process that balanced the volatile fatty acids (VFA). The methane produced was 0.45 m3 CH4/kg VS, whereas 71% of the chemical oxygen demand (COD) was removed. Thermophilic wet co-digestion was used to shorten the digestion and co-digestion phases. The results showed the highest methane was produced after 5 days (0.085 m3 CH4/(kgVSday), and 81% of total methane potential was attained after 9 days. The system proficiency for eliminating volatile solids was more than 36% after 6 days. Sludge recovery was 0.08 m3 sludge/m3 wastewater and water recovery was 0.85 (m3 sludge/m3 wastewater). It is suggested that wet co-digestion at a thermophilic state was favourable for the commercial application of co-digestion of aquaculture wastewater.