Co-treatment of sewage sludge and mature landfill leachate by anaerobic digestion

In this study, sewage sludge was co-digested with different amounts of mature landfill leachate (0, 5, 10, 20, and 40% v/v) to evaluate the yield capacities of biogas and CH4. The highest biogas yield was obtained from the treatment with 10% leachate dose (T2) and control with 0% leachate dose, while the lowest biogas was produced from the treatment with 40% leachate dose. The highest CH4 production (maximum yield per kg VS consumed) was also obtained from T2, which was about 36% (v/v) higher than the control. This result was confirmed by the first-order kinetic model. It was also observed that the COD, TS, and VS removal efficiencies significantly decreased with increasing the leachate dose. However, the increased dose of leachate did not inhibit TN removal efficiency. This study demonstrates that mature landfill leachate could be treated via anaerobic co-digestion process with sewage sludge to enhance biogas production at low doses (up to 20% v/v).