2022/4/1/ · This batch experiment used 3 L WAS and five 1 L fermenters for anaerobic fermentation, and each fermenter was filled with 600 mL WAS. Lignin at different dosages of 0, 0.4761, 0.9522, 1.4283 and 1.9044 g were then added into these fermenters to attain the desired lignin level (lignin/VSS) of 0, 5, 10, 15 and 20%.