Microbial analysis of anaerobic digester reveals prevalence of manure microbiota

• Published in: Journal of water process engineering 2024-04, Vol.60, p.105162, Article 105162
• Main Authors: García Álvaro, Alfonso, Ruiz Palomar, César, Valenzuela, Edgardo I., Hermosilla Redondo, Daphne, Muñoz Torre, Raúl, de Godos Crespo, Ignacio
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Inhibition; Microbial community; Swine manure; Waste to energy
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.105162

Anaerobic digestion of swine manure reduces farm greenhouse gases emissions and provides a renewable gas in the agricultural sector. The particular composition of manure, with high concentrations of ammoniacal nitrogen and volatile fatty acids, often threatens the stability of the process through inhibition of methanogens. In this work, continuous production of biogas was tested under relative short hydraulic retention time (15 days). Although a strong inhibition period was detected, adaptation of the microbiota and displacement of bacteria and archaea present in the inoculum by microorganisms present in the animal manure resulted in biogas production close to the values found in standardized batch tests in absence of inhibitions. These findings suggest that in anaerobic digestion of manure, it is not necessary to inoculate, as manure itself contains a large number of active fermentative microorganisms that can even resist long-term digestion inhibition. [Display omitted] •A strong inhibition was surpassed after an operation period of 70 days.•Volatile fatty acids and ammonium were identified as main inhibitors.•After the inhibition period, a production close to the batch tests was attained.•Microorganisms present in the swine manure displaced those of the inoculum.