Subbarao Paruchuri M V, D' Silva Tinku Casper, Adlak Komalkant, Kumar Subodh, Chandra Ram, Vijay Virendra Kumar
Department of Mechanical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
Environ Res. 2023 Oct 1;234:116286. doi: 10.1016/j.envres.2023.116286. Epub 2023 May 30.
Carbon emissions and associated global warming have become a threat to the world, the major contributor being the extensive use of fossil fuels and uncontrolled generation of solid wastes. Energy generation from renewable energy sources is considered an alternative to achieving carbon neutrality. Anaerobic digestion (AD) is a sustainable technology that has been endorsed as a low-carbon technology complimenting both waste management and renewable energy sectors. The AD technology recovers the volatile matter from waste biomass as much as possible to produce biogas, thus reducing carbon emission as compared to open dumping or burning. However, there is a need of compilation of information on how each subsystem in AD contributes to the overall carbon neutrality of the entire system and chances of achieving a circular economy along with it. Therefore, this article aims to clarify the associated internal and external factors that determine the low carbon characteristic of anaerobic digestion technology. From this review, the potential of AD system for energy-atmosphere-agriculture nexus has been explored. Carbon emission mapping of the potential entities involved in AD were identified and perspective to life cycle assessment and future research direction has been pointed out. Climate change impact and acidification potential are the two entities that can influence the overall environmental sustainability of an AD system. It was recognized that each stage of AD system starting from substrate supply chain, biogas production, upgradation, utilization, and digestate application had a remarkable effect on the overall carbon emission potential based on its design, operation, and maintenance. Selection of suitable substrates and co-digesting them together for improved biogas production rate with high methane content and proper digestate post-processing and storage can vastly reduce the carbon emission potential of the AD technology. Further, a case scenario of India was assessed considering the utilization of major surplus biomass available through AD. Re-routing the three major substrates such as agricultural crop residues, animal wastes and organic fraction of municipal solid wastes through AD can reduce at least 3.5-3.8 kg CO per capita of annual carbon emission load in India. Furthermore, the pathways in which the policy and legislations over establishment of AD technology and how to explore linkages between achieving circular economy and low carbon economy for Indian scenario has been highlighted.
碳排放以及相关的全球变暖已成为对世界的一种威胁，主要原因是化石燃料的广泛使用和固体废物的无节制产生。利用可再生能源发电被视为实现碳中和的一种替代方案。厌氧消化（AD）是一项可持续技术，已被认可为一种低碳技术，对废物管理和可再生能源领域都有补充作用。AD技术尽可能从废弃生物质中回收挥发性物质以生产沼气，因此与露天倾倒或焚烧相比，减少了碳排放。然而，需要汇编有关AD中的每个子系统如何对整个系统的整体碳中和做出贡献以及随之实现循环经济的可能性的信息。因此，本文旨在阐明决定厌氧消化技术低碳特性的相关内部和外部因素。通过本次综述，探索了AD系统在能源 - 大气 - 农业关系方面的潜力。确定了AD中潜在实体的碳排放图谱，并指出了生命周期评估的前景和未来研究方向。气候变化影响和酸化潜力是可以影响AD系统整体环境可持续性的两个因素。人们认识到，AD系统从底物供应链、沼气生产、升级、利用到沼渣应用的每个阶段，基于其设计、运行和维护，对整体碳排放潜力都有显著影响。选择合适的底物并将它们共同消化以提高沼气生产率、增加甲烷含量，并进行适当的沼渣后处理和储存，可以大幅降低AD技术的碳排放潜力。此外，考虑到通过AD利用印度主要剩余生物质的情况，对印度的一个案例进行了评估。通过AD重新规划农业作物残渣、动物粪便和城市固体废物有机部分这三种主要底物的处理路径，可使印度人均每年的碳排放负荷至少减少3.5 - 3.8千克二氧化碳。此外，还强调了在印度建立AD技术的政策和法规途径，以及如何探索实现循环经济和低碳经济之间的联系。
