Abstract

Anaerobic digestion (AD) is a well-known process with potential applications in the energy sector and waste management. The generation of digestate material during the AD process is considered a waste material. Although agriculture is a significant end-user of digestate, the surplus nutrient content, agricultural crop requirements, escalating transport costs, regulatory demands, and market acceptance constitute significant hurdles for utilizing digestate in agriculture alone. Many new innovative technologies are being developed as alternative approaches for digestate management and related options. Anaerobic digestate incorporates versatile characteristics including essential plant nutrients, enzymes, extracellular polysaccharides and trace elements. These properties give the AD digestate much application potential when combined with the appropriate treatments and valorization process. Microbial bioconversion, fermentation, hydrothermal carbonization, pyrolysis, Vacuum thermal stripping, Nijhuis Ammonium Recovery, Electrodialysis, Trans Membrane Chemi Sorption, Osmotic membrane bioreactor, chemical precipitation, Catalytic decomposition are the important processes commonly used to valorize the AD digestate. The AD digestate can be used as an organic amendment in agriculture, a substrate for algae cultivation, nitrogen and phosphorus extraction, energy production, synthesis of hydrochar and pyrochar for pollutants adsorption, energy storage and conversion, synthesis of various carbon and doped metal nanoparticles for photocatalytic activity and production of high-value chemicals. Among the multiple avenues open to applied research, some are entirely new. Hence, this review aims to incorporate recent research trends in AD digestate valorization, and subsequently generate knowledge on the preparation of novel products applicable to various sectors.

摘要

厌氧消化 (AD) 是一种众所周知的工艺，在能源领域和废物管理中具有潜在的应用。在 AD 过程中产生的消化物质被认为是一种废物。尽管农业是沼渣的重要最终用户，但过剩的营养成分、农作物需求、不断上升的运输成本、监管要求和市场接受度构成了仅在农业中利用沼渣的重大障碍。正在开发许多新的创新技术作为沼渣管理和相关选择的替代方法。厌氧消化物具有多种特性，包括必需的植物营养素、酶、细胞外多糖和微量元素。当与适当的处理和增值过程相结合时，这些特性使 AD 消化物具有很大的应用潜力。微生物生物转化、发酵、水热碳化、热解、真空热汽提、Nijhuis 氨回收、电渗析、跨膜化学吸附、渗透膜生物反应器、化学沉淀、催化分解是常用的重要工艺来使 AD 消化物增值。AD沼渣可用作农业有机改良剂、藻类培养的基质、氮磷提取、能源生产、水炭和焦炭的合成用于污染物吸附、能量储存和转化、各种碳和掺杂金属纳米粒子的合成用于光催化活性和高价值化学品的生产。在对应用研究开放的多种途径中，有些途径是全新的。因此，本综述旨在结合 AD 消化物增值的最新研究趋势，并随后产生有关制备适用于各个部门的新产品的知识。