In this study, a multi-objective optimization of sustainable integration of algal biofuel production using nutrient recycling technology, such as anaerobic digestion and hydrothermal liquefaction, is considered. Gross annual profitability and global warming potential (GWP) are the criteria chosen for the design of the algal biofuel production system. Three scenarios, such as full-scale (baseline), pilot-scale (conservative), and lab-scale (nominal), are chosen based on the expected maturity levels and nutrient demand. The results of the optimization produce Pareto sets of optimal solutions for acknowledging the trade-off between the economic and the environmental criteria of the integrated system. It is found that the anaerobic digestion (AD) technology shows better performance in terms of an environmental perspective, displacing the excessive fertilizer requirements due to its maturity in comparison with the hydrothermal liquefaction (HTL) process. However, HTL is a new, evolving, promising nutrient recycling technology which demonstrates economic preferences compared to the AD process due to its low cost of production.

中文翻译：

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利用集成营养循环技术优化藻类生物燃料可持续生产的生命周期

在这项研究中，考虑了利用营养循环技术（如厌氧消化和水热液化）对藻类生物燃料生产进行可持续整合的多目标优化。年度总利润和全球变暖潜能值（GWP）是设计藻类生物燃料生产系统时选择的标准。根据预期的成熟度和养分需求，选择了三种方案，例如满刻度（基准），中试刻度（保守）和实验室刻度（标称）。最优化的结果产生了帕累托最优解集，用于确认集成系统的经济和环境标准之间的权衡。发现从环境角度来看，厌氧消化（AD）技术显示出更好的性能，与水热液化（HTL）工艺相比，由于肥料成熟而替代了过多的肥料需求。但是，HTL是一种新的，不断发展的，有前途的养分循环技术，由于其生产成本低，与AD工艺相比，它表现出经济上的优势。