Abstract
Focusing on the influence of waste activated sludge ozonation, batch and continuous experiments were conducted to verify the synergistic effects of the anaerobic co-digestion of sewage sludge and food waste (FW). The results of the batch experiments confirmed that biogas production exceeded the predicted value by co-digestion. In the continuous experiments, 10%, 20%, and 30% of FW by weight were added to untreated and ozonated systems. In all cases, the biogas production increased efficiently. The net biogas production of FW was calculated to be higher than 918 NmL/g-VS for the 10% and 20% feedings. On the other hand, with 30% FW feeding, the net biogas production of FW in the untreated system dropped significantly to 665 NmL/g-VS, while that in the ozonated system remained as high as 1036 NmL/g-VS. Therefore, it was clear that the ozonated system was superior to the untreated system under high organic loadings. Furthermore, the dewatering test results suggested that ozonated system are less likely to increase the weight of dewatered sludge even when FW is added.
