Improvement of the biomethanization of sewage sludge by thermal pre-treatment and co-digestion with strawberry extrudate
Improvement of the biomethanization of sewage sludge by thermal pre-treatment and co-digestion with strawberry extrudate
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DOI：
10.1016/j.jclepro.2014.11.039
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发表时间：
2015-03
影响因子：
11.1
通讯作者：
A. Serrano;J. Siles;M. Gutiérrez;M. Martín
中科院分区：
文献类型：
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作者：
A. Serrano;J. Siles;M. Gutiérrez;M. Martín
由于污水污泥的高污染性，其管理在发达国家是一个重要问题。生物甲烷化是一种广泛采用的技术，但其存在甲烷产量低、生物降解性差、对营养失衡高度敏感等缺点。本文提出了一种热预处理（120°C，2atm），通过溶解残留原料中的有机物来提高污水污泥和草莓压榨物的生物甲烷化产率。此外，还评估了污水污泥与草莓挤出物的共同消化，因为这种联合处理可以增强污水污泥的营养平衡并稀释抑制剂。因此，本研究的主要目的是联合评估这种废物的预处理和共消化，这在文献中从未描述过。研究发现，对污水污泥进行 15 分钟的单独热预处理后，可溶性碳浓度（主要为挥发性脂肪酸）、氮和磷分别增加了 165%、16% 和 24%。相比之下，草莓挤出物的可溶性碳、氮和磷浓度变化分别低至 10%、32% 和 43%。随后的各项生物甲烷化测试表明，底物溶解和甲烷产量提高之间存在正相关关系，污水污泥和草莓压榨物的甲烷产量分别增加了约 29% 和 16%。此外，未经预处理的污水污泥和草莓挤出物的共同消化增强了稳定性并稀释了消化池内的氮浓度，尽管甲烷产量略低于预期。相比之下，最合适的组合是预处理的污水污泥和生草莓挤出物的共同消化，因为它也很稳定，但在甲烷生产方面表现出协同作用（237 ± 29 mLSTP/g VS；STP：0 °C，1 atm）。这种联合处理可能被认为是两种污染废物联合处理的一个有趣的替代方案。
The management of sewage sludge is an important issue in developed countries due to the highly polluting character of this waste. Biomethanization is a widely employed technology for this purpose, although it has several disadvantages such as low methane yield, poor biodegradability, and high sensitivity to nutrient imbalance. In this paper, a thermal pre-treatment (120 °C, 2 atm) is proposed to improve the biomethanization yield of sewage sludge and strawberry extrudate by solubilizing organic matter from the residual raw materials. Additionally, the co-digestion of sewage sludge with strawberry extrudate is evaluated as this combined treatment allows enhancing the nutrient balance and diluting inhibitors from sewage sludge. Therefore, the main aim of this study is the joint evaluation of the pre-treatment and co-digestion of this waste, which has never been described before in literature. The individual thermal pre-treatment of sewage sludge for 15 min was found to increase the soluble carbon concentration (mainly as volatile fatty acids), nitrogen, and phosphorus by 165%, 16%, and 24%, respectively. In contrast, the variation in the concentration of soluble carbon, nitrogen, and phosphorus for strawberry extrudate was as low as 10%, 32%, and 43%, respectively. Subsequent individual biomethanization tests showed a positive relationship between substrate solubilization and methane yield enhancement, with an increase of around 29% and 16% for sewage sludge and strawberry extrudate, respectively. Moreover, the co-digestion of sewage sludge and strawberry extrudate, both without pre-treatment, enhanced the stability and diluted the nitrogen concentration inside the digesters, although the methane yield was slightly lower than expected. In contrast, the most suitable combination was found to be the co-digestion of pre-treated sewage sludge and raw strawberry extrudate as it was also stable, but showed a synergy in methane production (237 ± 29 mLSTP/g VS; STP: 0 °C, 1 atm). This combined treatment might be considered an interesting alternative for the combined treatment of both polluting wastes.