Abstract The highest economic and environmental costs of wastewater treatment plants are related to waste disposal, which is mainly sludge disposal, and energy supply. Such challenges are even more critical in islands, where there are many environmental, landscape, and geographical constraints that make the use of conventional technologies difficult. For this reason, a geothermal energy system for wastewater and sludge treatment, and power production is proposed. Such a system is assessed through an exergoeconomic analysis, performed in Engineering Equation Solver environment, that allows determining the exergoeconomic costs of geo-fluid, electricity production, and sludge drying. The sensitivity analyses, carried out to assess the effect of several design parameters, have highlighted that the geothermal source temperature significantly affects the system operation and consequently the exergoeconomic costs, which range 77–95 c€/kWhex for sludge treatment and between 4.8 and 6.6c€/kWhex for electricity production. Finally, multivariate optimization has been carried out to find the conditions that minimize the exergoeconomic costs of the system. The total hourly exergoeconomic cost of the system products, namely sludge and electricity, is minimized when the geothermal source temperature is equal to 110 °C and the 58.91% of the desiccant flow is recycled. Overall, this study outlines that an exergy-based economic analysis is fundamental to assess the economic viability of innovative integrated solutions based on renewables.

中文翻译：

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用于废水和污泥处理的地热能：一个exergoeconomic 分析

摘要 污水处理厂最高的经济和环境成本与废物处理有关，主要是污泥处理和能源供应。这些挑战在岛屿上更为严峻，因为那里有许多环境、景观和地理限制，使得传统技术的使用变得困难。为此，提出了一种用于废水和污泥处理以及发电的地热能系统。这种系统是通过在工程方程求解器环境中执行的放热经济分析进行评估的，该分析允许确定地层流体、电力生产和污泥干燥的放热经济成本。敏感性分析，用于评估几个设计参数的影响，强调地热源温度显着影响系统运行，因此影响了exergoeconomic 成本，污泥处理的范围为 77-95 c€/kWhex，电力生产的范围为 4.8 到 6.6c€/kWhex。最后，进行了多变量优化以找到使系统的exergoeconomic 成本最小化的条件。当地热源温度等于 110°C 并且 58.91% 的干燥剂流被回收时，系统产品，即污泥和电力的每小时总发电经济成本最小。总体而言，本研究概述了基于火用的经济分析对于评估基于可再生能源的创新集成解决方案的经济可行性至关重要。污泥处理为 77-95 c€/kWhex，电力生产为 4.8 到 6.6 c€/kWhex。最后，进行了多变量优化以找到使系统的exergoeconomic 成本最小化的条件。当地热源温度等于 110°C 并且 58.91% 的干燥剂流被回收时，系统产品，即污泥和电力的每小时总发电经济成本最小。总体而言，本研究概述了基于火用的经济分析对于评估基于可再生能源的创新集成解决方案的经济可行性至关重要。污泥处理为 77-95 c€/kWhex，电力生产为 4.8 到 6.6 c€/kWhex。最后，进行了多变量优化以找到使系统的exergoeconomic 成本最小化的条件。当地热源温度等于 110°C 并且 58.91% 的干燥剂流被回收时，系统产品，即污泥和电力的每小时总发电经济成本最小。总体而言，本研究概述了基于火用的经济分析对于评估基于可再生能源的创新集成解决方案的经济可行性至关重要。当地热源温度等于 110°C 并且 58.91% 的干燥剂流被回收时，系统产品，即污泥和电力的每小时总发电经济成本最小。总体而言，本研究概述了基于火用的经济分析对于评估基于可再生能源的创新集成解决方案的经济可行性至关重要。当地热源温度等于 110°C 并且 58.91% 的干燥剂流被回收时，系统产品，即污泥和电力的每小时总发电经济成本最小。总体而言，本研究概述了基于火用的经济分析对于评估基于可再生能源的创新集成解决方案的经济可行性至关重要。