Enhancement of Fermentation Performance in the Anaerobic Co-Digestion of Chicken Manure and Corn Straw under Biogas Slurry Reflux via Air Stripping of the Digestate

Jiaoning Zhu; Jingxuan Zhang; Yun Tang; Xiaoyuan Zhang; Xiangyuan Shi; Xiuhong Wang; Yongping Li

doi:10.3390/agronomy14081794

Agronomy (Aug 2024)

Enhancement of Fermentation Performance in the Anaerobic Co-Digestion of Chicken Manure and Corn Straw under Biogas Slurry Reflux via Air Stripping of the Digestate

Jiaoning Zhu,
Jingxuan Zhang,
Yun Tang,
Xiaoyuan Zhang,
Xiangyuan Shi,
Xiuhong Wang,
Yongping Li

Affiliations

Jiaoning Zhu: Shanxi Institute of Organic Dryland Farming, Shanxi Agricultural University, Taiyuan 030031, China
Jingxuan Zhang: College of Resources and Environment, Shanxi Agricultural University, Taiyuan 030031, China
Yun Tang: Shanxi Institute of Organic Dryland Farming, Shanxi Agricultural University, Taiyuan 030031, China
Xiaoyuan Zhang: Shanxi Institute of Organic Dryland Farming, Shanxi Agricultural University, Taiyuan 030031, China
Xiangyuan Shi: Shanxi Institute of Organic Dryland Farming, Shanxi Agricultural University, Taiyuan 030031, China
Xiuhong Wang: Shanxi Institute of Organic Dryland Farming, Shanxi Agricultural University, Taiyuan 030031, China
Yongping Li: Shanxi Institute of Organic Dryland Farming, Shanxi Agricultural University, Taiyuan 030031, China

DOI: https://doi.org/10.3390/agronomy14081794
Journal volume & issue: Vol. 14, no. 8
p. 1794

Abstract

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Ammonium inhibition is a key limiting factor for anaerobic digestion when using chicken manure as the main substrate, especially in a digestion system with biogas slurry reflux. Air stripping is usually used as a recycled biogas slurry treatment. In this study, we carried out the anaerobic co-digestion of chicken manure and corn straw. The fermentation performance was investigated with and without air stripping at different biogas slurry reflux ratios and with an increasing organic loading rate. The results show that air stripping enhanced biogas production, system stability, and volatile solid removal efficiency via the mitigation control of ammonium inhibition. The total ammonium nitrogen in the digesters with air stripping was 20.24–46.40% lower than in those without air stripping. The highest specific biogas production and volatile solid removal efficiency values were obtained in the digesters at an organic loading rate of 3.3 g volatile solid (VS)/(L·d) and a reflux ratio of 75% with air stripping, reaching 480.43 mL/gVSadd and 63.36%, respectively. Moreover, air stripping also improved the organic loading rate and reflux ratio. Stable operation was achieved at an organic loading rate of 5.3 gVS/(L·d) and a reflux ratio of 75%, with specific biogas production of 392.35 mL/gVSadd and a volatile solid removal efficiency of 50.33%. The fermentation performance deteriorated when the organic loading rate was increased to 8.0 gVS/(L·d) at a reflux ratio of 75%, even when air stripping was conducted, indicating that a slighter lower reflux ratio (50%) could be more feasible at a higher organic loading rate (8.0 gVS/(L·d). Additionally, the methanogen community structure varied according to the use of air stripping, with a shift in the methanogenic pathway from hydrogenotrophic to acetoclastic methanogens. Overall, our findings support the adoption of air stripping for ammonium mitigation in anaerobic digestion with biogas slurry reflux.

Published in Agronomy

ISSN: 2073-4395 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Agriculture
Website: http://www.mdpi.com/journal/agronomy

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