TY CONF TI USE OF VARIOUS AGRICULTURAL WASTES AS BIOGAS SOURCES KW biogas KW agricultural waste KW anaerobic digestion KW co-digestion KW methane KW renewable energy KW organic fertilizers JO INDUSTRIAL THERMAL POWER ENGINEERING AU Erofeev, M.S. AU Solzhenikin, P.A. AU Portnov, V.V. AU Dubanin, V.Y. PY 2026 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov