School of Energy Science and Engineering, Central South University, Changsha 410083, China.
School of Energy Science and Engineering, Central South University, Changsha 410083, China.
Sci Total Environ. 2020 Dec 15;748:142383. doi: 10.1016/j.scitotenv.2020.142383. Epub 2020 Sep 17.
Hydrothermal carbonization (HTC)/liquefaction (HTL)/gasification (HTG) are promising processes for biofuel production from biomass containing high moisture. However, wastewater, the aqueous phase (AP) byproduct from these hydrothermal processes, is inevitably produced in large amounts. The AP contains >20% of the biomass carbon, and the total organic carbon in AP is as high as 10-20 g/L. The treatment and utilization of AP are becoming a bottleneck for the industrialization of hydrothermal technologies. The major challenges are the presence of various inhibitory substances and the high complexity of AP. Bioenergy recovery from AP has attracted increasing interest. In the present review, the compositions and characteristics of AP are first presented. Then, the progress in recovering bioenergy from AP by recirculation as the reaction solvent, anaerobic digestion (AD), supercritical water gasification (SCWG), microbial fuel cell (MFC), microbial electrolysis cell (MEC), and microalgae cultivation is discussed. Recirculation of AP as reaction solvent is preferable for AP from biomass with relatively low moisture; AD, MFC/MEC, and microalgae cultivation are desirable for the treatment of AP produced from processing biomass with low lignin content at relatively low temperatures; SCWG is widely applicable but is energy-intensive. Finally, challenges and corresponding strategies are proposed to promote the development of AP valorization technologies. Comprehensive analysis of AP compositions, clarification of the mechanisms of valorization processes, valorization process integration detoxification of AP, polycultures and co-processing of AP with other waste, enhancement in pollutant removal, scaling-up performance, and the techno-economic analysis and life-cycle assessment of valorization systems are promising directions in future investigations.
水热碳化（HTC）/液化（HTL）/气化（HTG）是从高水分生物质生产生物燃料的有前途的方法。然而，这些水热过程不可避免地会产生大量的废水，即水相（AP）副产物。AP 中含有超过 20%的生物质碳，总有机碳在 AP 中高达 10-20g/L。AP 的处理和利用成为水热技术工业化的瓶颈。主要挑战是存在各种抑制物质和 AP 的高复杂性。从 AP 中回收生物能源引起了越来越多的关注。在本综述中，首先介绍了 AP 的组成和特性。然后，讨论了通过将 AP 再循环作为反应溶剂、厌氧消化（AD）、超临界水气化（SCWG）、微生物燃料电池（MFC）、微生物电解池（MEC）和微藻培养从 AP 中回收生物能源的进展。对于水分相对较低的生物质产生的 AP，再循环 AP 作为反应溶剂是可取的；对于在相对较低的温度下处理木质素含量较低的生物质加工产生的 AP，AD、MFC/MEC 和微藻培养是可取的；SCWG 应用广泛，但能源密集。最后，提出了挑战和相应的策略，以促进 AP 增值技术的发展。综合分析 AP 的组成，阐明增值过程的机制，增值过程集成 AP 的解毒，多培养物和 AP 与其他废物的共处理，增强污染物去除，放大性能，以及增值系统的技术经济分析和生命周期评估，是未来研究的有前途的方向。
