Experimental Evaluation of Automated Intermittent Pneumatic Mixing in Moisture-Controlled Anaerobic Digestion

Pochinok, Sergey; Lavrentyev, Alexey; Obozov, Alaibek; Sultanalieva, Raya; Kirova, Sairagul

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Proceedings of International Conference on Applied Innovation in IT · 2026/04/22 · Vol. 14 · Issue 2 · pp. 217–224

Experimental Evaluation of Automated Intermittent Pneumatic Mixing in Moisture-Controlled Anaerobic Digestion

Sergey Pochinok, Alexey Lavrentyev, Alaibek Obozov, Raya Sultanalieva, Sairagul Nasirdinova and Veronika Kirova

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Abstract

Stable anaerobic digestion depends on both substrate preparation and reproducible mixing conditions inside the bioreactor. This paper presents an experimental evaluation of automated intermittent pneumatic mixing combined with moisture-controlled substrate preparation for anaerobic digestion systems. Moisture content and dry matter fraction of a prepared corn silage substrate were determined by thermogravimetric analysis and used to calculate the required water addition for target moisture levels before reactor loading using a wet-basis mass-balance approach. The main experimental comparison was performed between manual pneumatic mixing and automated intermittent pneumatic mixing controlled by a time relay and solenoid valve. The automated mode provides repeatable gas injection into the distribution chamber, reduces operator-dependent variability, and improves the reproducibility of the mixing regime. Experimental results showed that automated intermittent mixing increased total biogas production from 99.35 m³ to 125.63 m³, corresponding to an absolute increase of 26.28 m³ and a relative improvement of 26.45% compared with manual operation. In addition, intermittent operation reduced compressor duty cycle compared with hypothetical continuous mixing, indicating potential energy savings during long-term operation. The study introduces operational performance indicators for comparing mixing modes and applies a practical moisture-standardization procedure for substrate preparation. Unlike previous studies focused separately on substrate preparation or mixing automation, the proposed approach integrates moisture-controlled substrate standardization, automated pneumatic mixing, and operational performance evaluation within a single experimental workflow. The proposed method can be applied to small and medium-scale biogas plants where simple, low-cost automation is preferable to complex control systems while improving process stability and biogas productivity.

Keywords

Anaerobic Digestion Pneumatic Mixing Automated Control Intermittent Mixing Biogas Yield Moisture Control Substrate Preparation.

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