Civil and Environmental Engineering, McIntire School of Commerce, University of Virginia, Charlottesville, Virginia 22904-4742, USA.
Environ Sci Technol. 2010 Mar 1;44(5):1813-9. doi: 10.1021/es902838n.
Algae are an attractive source of biomass energy since they do not compete with food crops and have higher energy yields per area than terrestrial crops. In spite of these advantages, algae cultivation has not yet been compared with conventional crops from a life cycle perspective. In this work, the impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming. The results indicate that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location. Only in total land use and eutrophication potential do algae perform favorably. The large environmental footprint of algae cultivation is driven predominantly by upstream impacts, such as the demand for CO(2) and fertilizer. To reduce these impacts, flue gas and, to a greater extent, wastewater could be used to offset most of the environmental burdens associated with algae. To demonstrate the benefits of algae production coupled with wastewater treatment, the model was expanded to include three different municipal wastewater effluents as sources of nitrogen and phosphorus. Each provided a significant reduction in the burdens of algae cultivation, and the use of source-separated urine was found to make algae more environmentally beneficial than the terrestrial crops.
藻类是一种很有吸引力的生物质能源，因为它们不与粮食作物竞争，而且单位面积的能量产量比陆生作物高。尽管有这些优势，但从生命周期的角度来看，藻类养殖还没有与传统作物进行比较。在这项工作中，使用随机生命周期模型确定了与藻类生产相关的影响，并将其与柳枝稷、油菜和玉米种植进行了比较。结果表明，无论种植地点如何，这些传统作物在能源利用、温室气体排放和水方面的环境影响都低于藻类。只有在总土地利用和富营养化潜力方面，藻类才具有优势。藻类养殖的巨大环境足迹主要是由上游影响驱动的，如对二氧化碳和肥料的需求。为了减少这些影响，可以利用烟道气，更广泛地说，可以利用废水来抵消与藻类相关的大部分环境负担。为了展示结合废水处理的藻类生产的好处，模型扩展到包括三种不同的城市废水作为氮和磷的来源。这三种来源都显著降低了藻类养殖的负担，而且发现分离的尿液的使用比陆生作物更有利于藻类的环境。
