1. Achinas S, Euverink GJW (2019) Effect of combined inoculation on biogas production from hardly degradable material. Energies 12(217):1–13
2. Akyol C (2020) In search of the optimal inoculum to substrate ratio during anaerobic co-digestion of spent coffee grounds and cow manure. Waste Manage Res 00:1–6
3. APHA (2005) Methods for the examination of water and wastewater, twentieth ed., American Public Health Association, American Water Works Association, and Water Environment Federation, Washington DC, USA
4. Appels L, Assche AV, Willems K, Degreve J, Impe JZ, Dewil R (2011) Peracetic acid oxidation as an alternative pre-treatment for the anaerobic digestion of waste activated sludge. Biores Technol 102:4124–4130
5. Apte A, Cheernam V, Kamat M, Kamat S, Kashikar P and Jeswani H (2013) Potential of using kitchen waste in a biogas plant. Int J Environ Sci Develop 4(4)