URBAN PRUNING WASTE: CARBON FOOTPRINT ASSOCIATED WITH ENERGY GENERATION AND PROSPECTS FOR CLEAN DEVELOPMENT MECHANISMS

ABSTRACT Modern society experiences a progressive transition towards less harmful environmental behavior to foster sustainability. This study evaluated the carbon footprint associated with three types of urban pruning waste disposal: sanitary landfill (usual destination), generation of electricity, and generation of heat. A study case was carried out in the municipality of João Pessoa, Northeast Brazil. The Life Cycle Assessment methodology was applied to the material and energy inputs associated with each urban pruning waste disposal scenario, and the impact evaluation method selected was IPCC 2013 GWP 100y, which expresses environmental impact in terms of greenhouse gas emissions. From the analyses carried out herein, it was concluded that the current practice (sanitary landfilling) presented the highest carbon footprint within the studied scenarios. The best scenario was the utilization of urban pruning waste for the generation of electricity, which presented a negative carbon footprint (avoided emissions).

摘要
现代社会正逐步转向环境友好型行为模式，以推动可持续发展。本研究针对三类城市修剪废弃物（urban pruning waste）处置方案的碳足迹（carbon footprint）开展评估，分别为卫生填埋（常规处置方式）、发电及供热。研究案例选取巴西东北部的若昂佩索阿市实施。本研究采用生命周期评价（Life Cycle Assessment）方法学，对各处置场景的物质与能源投入进行分析，并选用政府间气候变化专门委员会（IPCC）2013年全球增温潜势（Global Warming Potential，简称GWP）100年时间尺度标准开展环境影响评估，该标准以温室气体排放量作为环境影响的表征指标。基于本次研究的分析结果，可得出以下结论：在所评估的所有处置场景中，当前采用的卫生填埋处置方式的碳足迹最高；最优处置场景为利用城市修剪废弃物进行发电，该场景的碳足迹为负值（即实现了温室气体排放回避）。