Anaerobic digestion of solid wastes: process enhancements; synergistic effect of food waste on digestibility of lignocellulosic fibres

每天都有大量的垃圾被送往垃圾填埋场.这些废物中有很大一部分是有机的，自然分解后产生渗滤液和填埋气体，两者都对环境构成威胁。厌氧消化（AD）在没有氧气的情况下自然发生，因为微生物将有机材料分解为沼气，甲烷（CH 4）和二氧化碳（CO 2）的混合物。在工程反应器中利用这一过程可以捕获沼气以产生能量，并减少固体材料的处置量。* 一种新的AD治疗方法已被明确设计为在北美通用、强大且负担得起。这种AD方法的特点是没有能源密集型的固体废物混合。最近完成的一项研究计划（由NSERC CRDPJ 459122-13支持）表明，该技术确实是强大的和通用的，能够处理各种不同成分的有机废物。这项最近完成的研究得出了两个令人惊讶的发现：1）固体废物转化为沼气的总转化率（即，生物气产率）与在充分混合的搅拌槽反应器中获得的一样高，和2）食物废物的存在和消化显著增强了废物中木质纤维素纤维的消化。* 这个新提出的CRD计划的目的是研究实现如此高的沼气产量的基本原理，并确定对渥太华伦敦东区计划商业示范项目的设计和运行至关重要的工艺变量。最初研究中使用的相同实验室规模的两级厌氧消化池将升级并重新投入使用，并将进行一系列实验，以建立良好性能的基本基础。 在渥太华的一个按比例扩大的示范单位进行的工艺建模和验证将使结果得到真正的验证。

Vast quantities of garbage are sent to landfill every day. A significant fraction of this waste is organic and decomposes naturally to produce leachate and landfill gas, both threats to the environment. Anaerobic digestion (AD) occurs naturally in the absence of oxygen as microbes break down organic materials to biogas, a mixture of methane (CH4) and carbon dioxide (CO2). Harnessing this process in engineered reactors captures biogas to make energy and reduces the amount of solid material for disposal. ****A new novel approach to AD has been designed explicitly to be versatile, robust, and affordable in North America. This AD approach features no energy-intensive mixing of the solid waste. A recently completed research program (supported by NSERC CRDPJ 459122-13) demonstrated that the technology is indeed robust and versatile, and capable of treating a wide range of organic wastes of variable composition. Two surprising findings came from this recently completed research: 1) that overall solid waste conversion to biogas (i.e., the biogas yield) was as high as that achieved in well-mixed stirred tank reactors, and 2) that digestion of lignocellulosic fibers in the waste was significantly enhanced by the presence and digestion of food waste. ****The objective of this new proposed CRD program is to investigate the fundamental principles that enabled such high biogas yields, and to determine the process variables of critical importance to the design and operation of a planned commercial demonstration project in east end of Ottawa. The same laboratory-scale two-stage anaerobic digester used in the initial research will be upgraded and recommissioned for this purpose, and a series of experiments will be conducted to establish the fundamental basis underlying good performance. Process modelling and verification in a scaled-up demonstration unit in Ottawa will enable a true validation of the results.