Cascade utilization of rice straw for biogas production

• Published in: Environmental science and pollution research international Vol. 30; no. 17; pp. 50444 - 50456
• Main Authors: Chen, Guangyin, Cao, Hainan, Tang, Yaling, Ni, Keye, Wang, Jing, Wu, Pei
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2023; Springer Nature B.V
• Subjects: Anaerobiosis; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biofuels; Biogas; Crop yield; Crystallinity; Digestion; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Fourier analysis; Fourier transforms; Functional groups; Infrared analysis; Infrared spectroscopy; Lignocellulose; Methane; Organic matter; Oryza - chemistry; Refuse as fuel; Research Article; Rice; Rice straw; Sodium hydroxide; Straw; Utilization; Volatile solids; Waste Water Technology; Water Management; Water Pollution Control; NaOH treatment; Lignocellulose structure; Crop straw; The first digestion time; Anaerobic digestion; Optimization
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-023-25829-5

To improve the biogas yield of rice straw, an innovative cascade utilization process for biogas production was proposed using a method referred to as “the first digestion + NaOH treatment + the second digestion” (labeled FSD). Both the first digestion and the second digestion of all treatments were conducted at the initial total solid (TS) loading of straw of 6%. A series of lab-scale batch experiments were conducted to investigate the effect of first digestion time (5, 10, and 15 days) on biogas production and lignocellulose structure destruction of rice straw. The results showed that the cumulative biogas yield of rice straw using the FSD process was increased by 13.63–36.14% compared with the control (CK), and the highest biogas yield of 233.57 mL g –1 TS added was obtained when the first digestion time was 15 days (FSD-15). The removal rates of TS, volatile solids, and organic matter were increased by 12.21–18.09%, 10.62–14.38%, and 13.44–16.88%, respectively, compared with those of CK. The results of Fourier transform infrared spectroscopy analysis revealed that the skeletal structure of rice straw was not significantly destroyed after the FSD process, but the relative contents of functional groups in rice straw were changed. The FSD process accelerated the destruction of crystallinity of rice straw, and the lowest crystallinity index of 10.19% was obtained at FSD-15. The abovementioned results indicated that the FSD-15 process is recommended for cascade utilization of rice straw in biogas production.