Department of Earth and Environmental Sciences, Faculty of Science & Engineering, Macquarie University, Sydney, NSW 2109, Australia.
Department of Earth and Environmental Sciences, Faculty of Science & Engineering, Macquarie University, Sydney, NSW 2109, Australia.
Sci Total Environ. 2021 May 1;767:144355. doi: 10.1016/j.scitotenv.2020.144355. Epub 2020 Dec 28.
Life cycle assessment (LCA) is a promising tool to evaluate the environmental impacts of different technologies for sustainable waste management. This study employs LCA to assess environmental impacts of alternative scenarios for residual municipal solid waste (MSW) management in New South Wales (NSW) based on current conditions and policies. Six different scenarios including a baseline scenario (landfilling) were applied for NSW waste management for energy production and their impacts on environment. The initial results showed that the scenario 3 that employed anaerobic digestion for food waste, incineration for combustible waste and plastic waste, and landfilling for non-combustible waste produced electricity of 625 kWh/t, which was maximum compared to the other scenarios. LCA results further suggested that among all scenarios, scenario 5 (similar to scenario 3 except combustible waste was treated through gasification and plastic waste was recycled) has the lowest level of environmental burdens in global warming, freshwater and marine ecotoxicity, and human non-carcinogenic toxicity. The sensitivity analysis for energy conversion rates (23-30%) for incineration and plastic recycling rate (66-91.3%) for MSW was further conducted and the results showed that energy conversion rate of 30% makes scenario 3 more valuable for electricity generation and less impactful for ecosystems damage category compared to scenario 5. On the other hand, plastic recycling rate of 91.3% has the lowest environmental burdens and by decreasing recycling rate to 66% the environmental impacts increase; however, it was noticed that reduction in recycling rate does not make any change in the order of scenarios. Overall, the study suggests that each waste type in NSW should be treated with a specific technology to achieve the highest resource recovery and lowest environmental impacts where energy conversion and plastic recycling rates have significant impacts.
生命周期评估（LCA）是一种很有前途的工具，可用于评估不同可持续废物管理技术的环境影响。本研究采用 LCA 评估了新南威尔士州（NSW）基于当前条件和政策的剩余城市固体废物（MSW）管理替代方案的环境影响。针对 NSW 废物管理的 6 种不同方案（包括基准方案填埋场），用于生产能源和对环境的影响。初步结果表明，方案 3 采用厌氧消化处理食物垃圾、焚烧处理可燃垃圾和塑料垃圾、以及填埋处理不可燃垃圾，可产生 625kWh/t 的电力，与其他方案相比最高。LCA 结果进一步表明，在所有方案中，方案 5（与方案 3 相似，除了可燃垃圾通过气化处理和塑料垃圾回收）在全球变暖、淡水和海洋生态毒性以及人类非致癌毒性方面的环境负担最低。进一步对焚烧的能源转化率（23-30%）和 MSW 塑料回收率（66-91.3%）进行了敏感性分析，结果表明，与方案 5 相比，焚烧的能源转化率为 30%，使方案 3 更有利于发电，对生态系统破坏类别影响较小。另一方面，塑料回收率为 91.3%时环境负担最低，而将回收率降低至 66%会增加环境影响；但是，需要注意的是，降低回收率不会改变方案的顺序。总体而言，本研究表明，NSW 的每种废物类型都应采用特定的技术进行处理，以实现最高的资源回收和最低的环境影响，其中能源转化率和塑料回收率有重大影响。
