Optimised percolate recirculation strategy for batch dry anaerobic digestion

间歇式干式厌氧消化的优化渗滤液再循环策略

• 批准号: 2737182
• 金额: --
• 依托单位: CRANFIELD UNIVERSITY
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2737182
• 关键词: Optimised; percolate; recirculation; strategy; batch

Dry-batch anaerobic digestion (AD) is an increasingly used treatment for the organic fraction of municipal solid waste (OFMSW), avoiding disposal to landfill of millions of tonnes every year while allowing for renewable energy production from waste. Despite the well-known benefits, dry ADs are associated with operational problems resulting from operation at solids contents 20%, including localised accumulation of inhibitors (e.g. volatile fatty acids (VFA), free ammonia), poor mixing, limited treatment capacity, slow reaction kinetics and biogas yields much lower than those attainable in laboratory scale. Addition of inoculum to the feedstock is one of the most common strategies attempting to solve inhibition problems, but it reduces volume available for waste treatment. Recent studies have proposed recirculation of percolate formed during dry AD as an alternative or in combination to inoculum addition. The resulting benefits are capped by the lack of scientific understanding of the mechanisms by which process is improved. Therefore, this study aims to investigate an optimised percolate recirculation strategy that can maximise biogas production and treatment capacity in dry digestion units operated in batch mode, and to do so for the several feedstocks most commonly used in dry AD. The specific objectives to fulfil the aim are: 1) Elucidate the mechanisms by which percolate recirculation improves dry AD performance2) Determine suitability of percolate recirculation to mitigate localised inhibition due to ammonia or VFA accumulation3) Propose a percolate recirculation strategy (volume and frequency) that allows optimal biogas generation and treatment capacity4) Understand required variations on percolate recirculation strategies depending on feedstock type and use or not of bulking agents5) Quantify benefits of a dynamic percolate recirculation strategy that varies during batch fermentation according to evolution of substrate degradationThis project is a collaboration between Cranfield University (UK) and UTC (France) and will require the student to spend approximately half of the PhD time on each institution.

干式厌氧消化 (AD) 是一种越来越多地用于城市固体废物 (OFMSW) 有机部分的处理方法，每年避免将数百万吨废物填埋，同时允许从废物中生产可再生能源。尽管干式 AD 具有众所周知的优点，但其在固体含量为 20% 的条件下操作会带来一些操作问题，包括抑制剂（例如挥发性脂肪酸 (VFA)、游离氨）的局部积累、混合不良、处理能力有限、反应动力学缓慢以及沼气产量远低于实验室规模的产量。在原料中添加接种物是试图解决抑制问题的最常见策略之一，但它减少了可用于废物处理的体积。最近的研究提出，将干 AD 期间形成的渗滤液再循环作为接种物添加的替代方案或组合。由于缺乏对改进流程的机制的科学理解，所带来的好处受到限制。因此，本研究旨在研究一种优化的渗滤液再循环策略，该策略可以最大限度地提高以间歇模式运行的干消化装置中的沼气产量和处理能力，并针对干法厌氧消化中最常用的几种原料做到这一点。实现这一目标的具体目标是： 1) 阐明渗滤液再循环改善干 AD 性能的机制 2) 确定渗滤液再循环是否适合减轻氨或 VFA 积累造成的局部抑制 3) 提出渗滤液再循环策略（体积和频率），以实现最佳沼气生成和处理能力 4) 了解根据原料类型和用途，渗滤液再循环策略所需的变化 或不使用填充剂5) 量化动态渗滤液再循环策略的好处，该策略在批量发酵过程中根据底物降解的演变而变化。该项目是克兰菲尔德大学（英国）和 UTC（法国）之间的合作项目，需要学生在每个机构花费大约一半的博士时间。