Anaerobic co-digestion of sewage sludge and strawberry extrudate under mesophilic conditions

作者：Serrano Antonio; Siles Jose A; Chica Arturo F; Angeles Martin M

来源：Environmental Technology, 2014, 35(23): 2920-2927.

DOI：10.1080/09593330.2014.925512

• sewage sludge
• strawberry extrudate
• mesophilic anaerobic co-digestion
• volatile fatty acids
• digestate

The biomethanization of sewage sludge has several disadvantages such as low methane yield, poor biodegradability and nutrient imbalance. In this paper, a sewage sludge and strawberry extrudate mixture in a proportion of 40: 60 (wet weight) is proposed to improve the viability of the process. The addition of an easily biodegradable co-substrate enhanced the nutrient balance and diluted the heavy metals and inhibitors from sewage sludge. Two different experimental set-ups at lab and semi-pilot scale were employed in order to ensure the reproducibility and significance of the obtained values. Co-digestion improved the stability of the process by decreasing the alkalinity to a mean value of 3215 +/- 190 mg CaCO3/L, while maintaining the pH within the optimal range for anaerobic digestion. The methane yield coefficient and biodegradability were 176 L/kg VS (total volatile solids) (0 degrees C, 1 atm) and 81% (VS), respectively. Kinetic parameters decreased at the highest loads, suggesting the occurrence of a slowing down phenomenon. A quality organic amendment with a heavy metal content lower than the limits established under European legislation for agricultural applications was obtained from the digestate of the proposed treatment.

• 出版日期2014-12