Anaerobic Co-Digestion of Duckweed (Lemna Gibba) and Waste Activated Sludge

In this study duckweed (Lemna gibba) and waste activated sludge (WAS) were co-digested in different proportions with acclimatized anaerobic granular sludge (AAGS) in mesophilic conditions. The aim was to evaluate if the co-digestion could lead to an increased efficiency of methane production compared to digestion of waste activated sludge alone. Results indicate that co-digestion with both duckweed and WAS, in certain proportions i.e. T4, increased the methane generation compared with digestion at other proportions. The methane generation yield in treatment setup T4 was significantly higher than the calculated in many of the proportion. The Gompertz model fits well on the experimental data of the treatment setup T4. The values of correlation coefficient were achieved relatively higher (R ≥ 0.99). The trend was that of without pre-treatment, co-digestion of duckweed and WAS did not give the same synergy.