Pilot scale anaerobic co-digestion of municipal wastewater sludge with biodiesel waste glycerin

► Co-digestion was tested in 1200 L control and test anaerobic digesters. ► Six glycerin loading rates were applied to the test digester. ► The digesters' methane production, VS removal and COD removal were compared. ► The maximum upper loading limit that did not cause a process upset was identified.