Granular activated carbon stimulates biogas production in pilot-scale anaerobic digester treating agro-industrial wastewater - Demetrios Kalantzis; Ioannis Daskaloudis; Tim Lacoere; Athanasios S. Stasinakis; Demetris F. Lekkas; Jo De Vrieze; Michail S. Fountoulakis (Bioresource Technology, 2023)