Techniques for Enhancing Anaerobic Digestibility of Municipal Solid Waste

目前，污水处理的目标正在从公共卫生和环境保护转向营养物质和能量回收，这是由高能源成本和营养物质价值驱动的。城市固体废物能源被认为是未来最有前途的可再生能源之一。厌氧消化（AD）是有机废物转化为可再生能源和生物燃料的默认过程。AD是一个多步骤的过程，在这个过程中，复杂的有机化合物被转化为最氧化和还原的形式，如单原子二氧化碳和甲烷。近年来，在有机废物处理中的应用得到了极大的发展。AD的吸引力是由于该过程的各种好处：(a)产生的沼气节能环保，(b)产生的浆液（消化液）富含氮，可用于农业作为营养肥和/或有机改良剂，(c)最近的应用是将消化液转化为生物炭，可进一步用作土壤增强剂或用于净化废水或烟道气体的吸附剂。AD的主要缺点是停留时间长（一般为20-30天），有机物的整体降解效率较低，部分原因是厌氧微生物无法有效降解某些有机化合物。尽管在城市固体废物领域进行了各种努力，但对这一过程尚未完全了解，目前的技术，特别是在上述领域，仍需要进一步发展和优化。

The goals of wastewater treatment are currently changing from public sanitation and environmental protection towards nutrient and energy recovery, which are driven by the high cost of energy and value in nutrients. Energy from municipal solid waste is considered to be one of the most promising future renewable energy sources. Anaerobic digestion (AD) is the default process for the biological conversion of organic waste to renewable energy and biofuel. AD is a multi-steps process in which the complex organic compounds are converted to the most oxidized and reduced form such as mono-atomic carbon dioxide and methane. In recent years, the application of AD for the treatment of organic waste has emerged dramatically. The attractiveness of AD is due to the various benefits of the process: (a) the produced biogas is energy efficient and environmentally friendly, (b) the produced slurry (digestate) is nitrogen rich and can be utilized in agriculture as a nutrient fertilizer and/or organic amendment, (c) a more recent application is to transform the digestate into biochar, which can be further employed as soil enhancer or an adsorbent for the purification of wastewater or flue gas. The major drawbacks of AD are its long retention time (typical 20-30 days) and the low overall degradation efficiency of organic matter, which is partly caused by the inability of the anaerobic microorganisms to degrade certain organic compounds efficiently. In spite of all the efforts in the AD of municipal solid waste sector, the process is not yet fully understood, and further development and optimization of the current technology, especially in the above-mentioned areas, is still needed.