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Updated: Feb 16, 2026
Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation
Published on: July 13, 2012
Effects of digestate recirculation on a two-stage anaerobic digestion system, particularly focusing on metabolite
Chuanfu Wu1, Qiqi Huang2, Miao Yu2
1Department of Environmental Engineering, School of Energy and Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China; Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 10083, China.
Abstract:
Single-stage (S-N treatment) and two-stage anaerobic digestion with (T-R treatment) and without digestate recirculation (T-N treatment) for methane production using food waste (FW) were comparatively evaluated to examine the effects of digestate recirculation on anaerobic digestion (AD). Digestate recirculation positively affected the methane yield and organic loading rate (OLR). Metabolite correlation analysis revealed that a systematic hydrolysis degree of greater than 75% is crucial to achieve the complete recoverable yield of methane from FW. Digestate recirculation also markedly increased the system alkalinity, maintaining an optimum pH for methanogens. However, the ammonium accumulated by T-R treatment would destroy the metabolic balance between the hydrolytic bacteria and methanogens, especially at a critical OLR. Therefore, the appropriate control of two-stage AD systems with digestate recirculation is limited not only to OLR regulation but also to the prevention of ammonium accumulation.
