Anaerobic-aerobic system for sustainable pig slurry wastewater treatment

Pig slurry is a highly energetic wastewater and a significant contributor to greenhouse gas emissions. Anaerobic digestion presents a reliable solution to address this issue, while providing efficient wastewater management. This study evaluated a combination of anaerobic and aerobic wastewater treatment for energy and nutrient recovery. Following 16 days acclimatization period, daily biogas production averaged 1.24 ± 0.43 NL with an average methane content of 80 ± 5%. This could theoretically result in the production of 1.85 kWh/d in energy. Regarding treatment efficiency, the combined anaerobic and aerobic treatments resulted in a COD removal of 85% and over 70% in solids removal. However, the removal of nitrogen and phosphorus were lower, at 38% and 45% respectively. Despite these limitations, the final concentration of nitrogen and phosphorus in the treated effluent allowed for its utilization as organic fertilizer, increasing its potential for spreading.