Effects of Biogas Slurry Recirculation on Anaerobic Digestion Performance of Maize Straw Silage

Abstract

In order to investigate the effects of slurry recirculation technology on anaerobic digestion performance of maize straw silage, maize straw silage was fermented with recirculated biogas slurry, and the gas production, pH value, methane content, volatile organic acids (VFAs) contents, chemical oxygen demand (COD) removal rate and other indicators were studied. The results showed that the fermentation time was positively correlated with daily gas production, methane content, cumulative gas production, VFAs and COD removal rate. Although the pH value fluctuated, it was still in the normal reaction range. The daily gas production was about 1.26 L. The acetic acid content increased first, then decreased, then increased, and finally stabilized. The biogas slurry recirculation technology saves water resources by 40 mL/d without affecting the normal gas production of anaerobic fermentation, and reduces the consumption of environmental resources. It has important development significance for the sustainable use of biomass resources

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