Rahman Kaniz Fatema, Abrar Md Farhatul, Tithi Sanjida Safa, Kabir Kazi Bayzid, Kirtania Kawnish
Department of Chemical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
Department of Chemical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
J Environ Manage. 2024 Nov;370:122850. doi: 10.1016/j.jenvman.2024.122850. Epub 2024 Oct 15.
Municipal solid waste (MSW) management is a major concern for Bangladesh, given its high population density and increasing waste production rate. Conventional waste management methods, such as landfilling, result in high carbon emissions for the environment. With over 70% of MSW being organic, hydrothermal carbonization (HTC) has emerged as a promising technology for recovering energy and nutrients from such heterogeneous waste streams. This study aimed to compare the environmental effects of HTC coupled with electricity generation (HTC-EG) from MSW with traditional landfilling using life cycle assessment in the context of Bangladesh. The HTC-EG scenario showed lower environmental impacts in three out of five impact categories, specifically reducing climate change, freshwater ecotoxicity, and photochemical ozone formation. For a functional unit of 6000-ton MSW, HTC-EG reduces the climate change impact by 7.7 × 10 kg CO eq. Additionally, HTC-EG has 46.77% less impact on freshwater ecotoxicity compared to landfilling and reduces the photochemical ozone formation impact by 1.86 × 10 NMVOC eq. However, the HTC-EG scenario leads to increased particulate matter formation and marine water eutrophication due to SO, SO, and PM2.5 emissions during hydrochar combustion and nitrate release from the liquid stream of the HTC reactor, respectively. Addressing these challenges through appropriate post-processing of flue gas from hydrochar combustion and HTC liquid streams could make HTC-EG a viable alternative to landfilling for MSW management in Bangladesh.
鉴于孟加拉国人口密度高且垃圾产生率不断上升，城市固体废物（MSW）管理是该国的一个主要问题。传统的垃圾管理方法，如填埋，会给环境带来高碳排放。由于超过70%的城市固体废物是有机的，水热碳化（HTC）已成为一种从这种异质废物流中回收能源和养分的有前景的技术。本研究旨在通过生命周期评估，比较孟加拉国城市固体废物水热碳化与发电（HTC-EG）和传统填埋对环境的影响。HTC-EG方案在五个影响类别中的三个类别中显示出较低的环境影响，特别是在气候变化、淡水生态毒性和光化学臭氧形成方面有所减少。对于6000吨城市固体废物的功能单元，HTC-EG将气候变化影响降低了7.7×10千克二氧化碳当量。此外，与填埋相比，HTC-EG对淡水生态毒性的影响降低了46.77%，并将光化学臭氧形成影响降低了1.86×10非甲烷挥发性有机化合物当量。然而，HTC-EG方案分别由于水热炭燃烧过程中的二氧化硫、三氧化硫和细颗粒物排放以及HTC反应器液流中的硝酸盐释放，导致颗粒物形成增加和海水富营养化。通过对水热炭燃烧烟气和HTC液流进行适当的后处理来应对这些挑战，可能会使HTC-EG成为孟加拉国城市固体废物管理中填埋的可行替代方案。
