Exploring stability indicators for efficient monitoring of anaerobic digestion of pig manure under perturbations. (15th May 2019)

• Record Type: Journal Article
• Authors: Sun, Hao; Ni, Ping; Angelidaki, Irini; Dong, Renjie; Wu, Shubiao
• Is Part Of: Waste management. Volume 91(2019)
• Page Start: 139
• Page End: 146
• Publication Date: 2019-05-15
• Subjects: Anaerobic digestion -- Pig manure -- Monitoring strategy -- Stability indicators -- Imbalance of microbial processes; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2019.05.008
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Stability indicators response varied in pig manure fermentation under perturbation. pH, biogas production or biogas contents is insensitive as early warning indicator. Propionic to acetic is efficient in predicting the fermentation process imbalance. Alkalinity ratios are also effective as stability indicators but less sensitive. Abstract: Monitoring of anaerobic digestion process is essential for achieving efficient and stable performance, thus requiring identification of effective stability indicators. The response of two experimental, continuously stirred tank reactors under mesophilic condition (fed with pig manure) was investigated to analyze the perturbation of organic and hydraulic overloading, and low-temperature shock. The pH was stably maintained in the range of 7.2–7.7, regardless of the presence of most simulated perturbation situations. Monitoring of biogas production and composition is important to reflect the current state of biogas process, but cannot predict the imbalance in the system. Accumulation of total VFAs up to 21, 718 mg/L was observed under the organic overloading condition (rapid increase of the organic loading rate of pig manure from 3 g VS/L/d to 9 g VS/L/d), but not for other perturbations. The ratio of propionate to acetate and that of intermediate alkalinity to partial alkalinity are rapidly altered in response to all perturbations, indicating their potential to function as stability indicators. However, the determination of the ratio of intermediate alkalinity to partial alkalinity can be performed by simple titration methods and be easily applied to actual projects without significant investment in advanced equipment and skilled operators.