Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Campus Box 7908, Raleigh, North Carolina 27695-7908, United States.
Environ Sci Technol. 2011 Sep 1;45(17):7438-44. doi: 10.1021/es103556m. Epub 2011 Aug 12.
Commercial food waste represents a relatively available high-quality feedstock for landfill diversion to biological treatment. A life-cycle assessment was performed for commercial food waste processed through aerobic composting systems of varying complexity, anaerobic digestion, and landfills with and without gas collection and energy recovery, as well as a bioreactor landfill. The functional unit was 1000 kg of food waste plus 550 kg of branches that are used as a bulking agent. For each alternative, global warming potential, NO(x) and SO(2) emissions, and total net energy use were determined. Anaerobic digestion was the most environmentally beneficial treatment option, leading to -395 kg net CO(2)e per functional unit. This result was driven by avoided electricity generation and soil carbon storage from use of the resulting soil amendment. The composting alternatives led to between -148 and -64 kg net CO(2)e, whereas the landfill alternatives led to the emission of -240 to 1100 kg CO(2)e. A traditional landfill with energy recovery was predicted to have lower emissions than any of the composting alternatives when a fertilizer offset was used. There is variation in the results based on uncertainty in the inputs, and the relative rankings of the alternatives are dependent on the soil amendment offset that is used. The use of compost to offset peat has greater emission offsets than the value of compost as a fertilizer.
商业厨余垃圾是一种相对易得的高质量原料，可用于替代传统的垃圾填埋方式，进行生物处理。本研究采用生命周期评估方法，对不同复杂程度的好氧堆肥系统、厌氧消化、有/无气体收集和能量回收的垃圾填埋场，以及生物反应器垃圾填埋场处理商业厨余垃圾的方案进行了评估。功能单位为 1000 公斤厨余垃圾和 550 公斤用作膨松剂的树枝。对每种替代方案，均测定了其全球变暖潜势、NO(x)和 SO(2)排放以及总净能耗。厌氧消化是最具环境效益的处理方案，每 1000 公斤功能单位可减少 -395 公斤净 CO(2)e。这一结果主要归因于避免了用电和土壤碳储存，因为可以利用产生的土壤改良剂。堆肥替代方案导致 -148 至 -64 公斤净 CO(2)e，而垃圾填埋替代方案导致 -240 至 1100 公斤 CO(2)e 的排放。如果使用肥料补偿，则预计传统的具有能量回收功能的垃圾填埋场的排放量低于任何一种堆肥替代方案。由于输入的不确定性，结果存在差异，替代方案的相对排名取决于使用的土壤改良剂补偿。与作为肥料的堆肥相比，用堆肥替代泥炭可获得更大的排放补偿。
