Department of Energy and Technology, Swedish University of Agricultural Sciences (SLU), Almas Allé 8, 750 07 Uppsala, Sweden.
Federal Institute of Education, Science and Technology Baiano (IF Baiano), Itapetinga, Bahia, Brazil.
Sci Total Environ. 2022 Sep 1;837:155777. doi: 10.1016/j.scitotenv.2022.155777. Epub 2022 May 8.
Implementation of resource recovery technologies is becoming increasingly important, as humans are exhausting the world's natural resources. Recovering nutrients and water from wastewater treatment systems will play an important role in changing the current trends towards a circular economy. However, guidance is still needed to determine the most appropriate way to do this. In this study two decision-support tools, sanitation planning software (Santiago) and life cycle assessment (LCA), were applied to identify appropriate technologies and their environmental impacts. As a case study, current and alternative scenarios for a wastewater treatment plant (WWTP) in Campo Grande, west-central Brazil, were used. Among 12 scenarios provided by Santiago for efficient nutrient recovery, eight were selected for further assessment. The current WWTP system (UASB reactors) resulted in the highest negative impacts in two of nine assessment categories (freshwater and marine eutrophication), due to nutrient discharge to water. A source separation scenario with urine stored in a urine bank and co-composting of feces showed best overall performance. Electricity consumption played a crucial role for impacts in several categories, while water consumption was not significantly affected by choice of toilet. One Santiago scenario matched the most appropriate scenario with the best environmental performance, but the other seven scenarios were not as beneficial, indicating a need for some adjustments in the software. These results highlight the importance of performing LCA to compare alternative scenarios, even when using a tool designed to identify locally appropriate technologies. The results also indicate that the current wastewater treatment system has reasonable environmental performance, but could be improved if measures were taken to recover energy and reuse water.
资源回收技术的实施变得越来越重要，因为人类正在耗尽世界上的自然资源。从废水处理系统中回收营养物质和水将在改变当前向循环经济发展的趋势方面发挥重要作用。然而，仍然需要指导来确定最合适的方法。在这项研究中，应用了两种决策支持工具，卫生规划软件（圣地亚哥）和生命周期评估（LCA），以确定合适的技术及其环境影响。作为一个案例研究，巴西中西部坎波格兰德的一个废水处理厂（WWTP）的当前和替代情景被用于研究。在圣地亚哥提供的 12 个有效养分回收情景中，选择了 8 个进行进一步评估。由于养分排入水中，当前的 WWTP 系统（UASB 反应器）在九个评估类别中的两个（淡水和海洋富营养化）中导致了最高的负面影响。带有尿液储存在尿液库中的源头分离情景和粪便的共同堆肥显示出最佳的整体性能。在几个类别中，电力消耗对影响起着至关重要的作用，而选择厕所对水消耗的影响并不显著。圣地亚哥的一个情景与具有最佳环境性能的最合适情景相匹配，但其他七个情景则没有那么有利，这表明该软件需要进行一些调整。这些结果强调了进行 LCA 以比较替代情景的重要性，即使使用旨在确定本地适用技术的工具也是如此。结果还表明，当前的废水处理系统具有合理的环境性能，但如果采取措施回收能源和再利用水，则可以进一步改进。
