Pechsiri Joseph Santhi, Thomas Jean-Baptiste E, Bahraoui Naoufel El, Fernandez Francisco Gabriel Acien, Chaouki Jamal, Chidami Saad, Tinoco Rodrigo Rivera, Martin Jose Pena, Gomez Cintia, Combe Michel, Gröndahl Fredrik
Water and Environmental Engineering, Department of Sustainable Development, Environmental Science and Engineering (SEED), KTH Royal Institute of Technology KTH, Teknikringen 10b, 114 28 Stockholm, Sweden.
Center for Energy Efficiency and Systems, Mines ParisTech, 60 Bd Saint-Michel, 75272 Paris, France; Setec Energie Environnement, 42-52 Quai de la Rapée, 75012 Paris, France.
Sci Total Environ. 2023 Jan 1;854:158445. doi: 10.1016/j.scitotenv.2022.158445. Epub 2022 Sep 1.
The versatility of microalgae biomass as candidates for various products and bioremediation needs motivates interests towards design and implementation of novel microalgae bioreactors. Conventional open-reactors are reliant on large quantities of sunlight and space while yields are constrained by outdoor environment conditions. Conversely, closed-reactor systems like bubble columns reduces these constrains on microalgae growth while occupying far less space at the expense of high energy demands, notably from lighting systems. A novel patented closed reactor design has recently been proposed that improves the bubble column concept with an efficient and effective lighting system. The present study uses Life Cycle Assessment approach to compare the environmental performance of conventional reactors and the proposed internally luminated novel closed reactor design, expressing impacts per kg biostimulant for the Scenedesmus almeriensis harvest from such units. All performance data was collected from a pilot facility in Almeria, Spain. Urban-industrial symbiosis scenarios are also portrayed in the study using wastewater and incinerator flue gas. Results show that under synthetic nutrient and carbon inputs in Spanish pilot operations, the cumulative energy demand for the novel photobioreactors is similar to conventional vertically-stacked horizon bioreactors but are substantially more demanding than conventional open reactors. However, when leveraging renewable energy sources and the photosynthesis process to consume wastestreams in urban-industrial symbiosis scenarios, the novel photobioreactor was able to achieve up to 80 % improvements in several impact categories e.g. eutrophication and climate change. Impact mitigation credits per kg dwt biomass across all energy scenarios in symbiosis amount to ≈1.8 kg COeq and ≈0.09 kg PO4 eq. This highlights that such closed and internally illuminated photobioreactors can be competitive with conventional reactors, and have potential to harness photosynthesis to reduce environmental burdens in an urban-industrial symbiosis setting. Possible economies of scale and the associated potential gains in efficiencies are further discussed.
微藻生物质作为各种产品和生物修复候选物的多功能性激发了人们对新型微藻生物反应器设计和实施的兴趣。传统的开放式反应器依赖大量阳光和空间，而产量受室外环境条件限制。相反，像鼓泡塔这样的封闭式反应器系统减少了对微藻生长的这些限制，同时占用空间少得多，但以高能量需求为代价，特别是来自照明系统的能量需求。最近提出了一种新颖的专利封闭式反应器设计，它通过高效的照明系统改进了鼓泡塔概念。本研究采用生命周期评估方法，比较传统反应器和提出的内部照明新型封闭式反应器设计的环境性能，以每千克生物刺激剂对从这些装置收获的阿尔梅里亚栅藻的影响来表示。所有性能数据均从西班牙阿尔梅里亚的一个试点设施收集。该研究还使用废水和焚烧炉烟气描绘了城市 - 工业共生情景。结果表明，在西班牙试点运营中的合成养分和碳输入条件下，新型光生物反应器的累积能源需求与传统垂直堆叠式水平生物反应器相似，但比传统开放式反应器的需求要高得多。然而，当在城市 - 工业共生情景中利用可再生能源和光合作用过程来消耗废水时，新型光生物反应器在几个影响类别（如富营养化和气候变化）中能够实现高达80%的改善。共生中所有能源情景下每千克干重生物质的影响缓解信用相当于约1.8千克二氧化碳当量和约0.09千克磷酸根当量。这突出表明，这种封闭式和内部照明的光生物反应器可以与传统反应器竞争，并且有潜力利用光合作用在城市 - 工业共生环境中减轻环境负担。进一步讨论了可能的规模经济和相关的潜在效率提升。
