On-field study of anaerobic digestion full-scale plants (Part I): An on-field methodology to determine mass, carbon and nutrients balance

► We looked for the mass balances of full-scale anaerobic digestion plants. ► We looked for a simple/reliable method for routine applications. ► We verified a linear equation as a tool for easily calculating input-output flows. ► This tool allowed determining carbon and nutrients balances in three full-scale plants. ► C, N, P, and K balances are necessary for digestate land applications as fertilizer.