Abstract:
Anaerobic digestion (AD) is a triple-benefit biotechnology for organic waste treatment, renewable production, and carbon emission reduction. In the process of anaerobic digestion, pH, temperature, organic load, ammonia nitrogen, VFAs, and other factors affect fermentation efficiency and stability. The balance between the generation and consumption of volatile fatty acids (VFAs) in the anaerobic digestion process is the key to stable AD operation. However, the accumulation of VFAs frequently occurs, especially propionate, because its oxidation has the highest Gibbs free energy when compared to other VFAs. In order to solve this problem, some strategies, including buffering addition, suspension of feeding, decreased organic loading rate, and so on, have been proposed. Emerging methods, such as bioaugmentation, supplementary trace elements, the addition of electronic receptors, conductive materials, and the degasification of dissolved hydrogen, have been recently researched, presenting promising results. But the efficacy of these methods still requires further studies and tests regarding full-scale application. The main objective of this paper is to provide a comprehensive review of the mechanisms of propionate generation, the metabolic pathways and the influencing factors during the AD process, and the recent literature regarding the experimental research related to the efficacy of various strategies for enhancing propionate biodegradation. In addition, the issues that must be addressed in the future and the focus of future research are identified, and the potential directions for future development are predicted.
摘要:
厌氧消化(AD)是有机废物处理的三重效益生物技术,可再生生产,和碳减排。在厌氧消化过程中,pH值,温度,有机负荷,氨氮,VFA,等因素影响发酵效率和稳定性。厌氧消化过程中挥发性脂肪酸(VFAs)的产生和消耗之间的平衡是AD稳定运行的关键。然而,VFA的积累经常发生,尤其是丙酸盐,因为与其他VFA相比,它的氧化具有最高的吉布斯自由能。为了解决这个问题,一些策略,包括缓冲加法,暂停喂食,降低有机负荷率,等等,已被提议。新兴方法,比如生物强化,补充微量元素,增加电子受体,导电材料,以及溶解氢的脱气,最近被研究过,呈现有希望的结果。但是这些方法的有效性仍然需要关于全面应用的进一步研究和测试。本文的主要目的是对丙酸酯的产生机制进行全面综述,AD过程中的代谢途径和影响因素,以及最近有关实验研究的文献,这些实验研究与增强丙酸生物降解的各种策略的功效有关。此外,确定了未来必须解决的问题和未来研究的重点,并预测了未来发展的潜在方向。