Sustainable Industrial Systems, School of Chemical Engineering and Analytical Science, The University of Manchester, The Mill, Sackville Street, Manchester, M13 9PL, UK; Tyndall Centre for Climate Change Research, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Pariser Building, Sackville Street, Manchester, M13 9PL, UK.
Sustainable Industrial Systems, School of Chemical Engineering and Analytical Science, The University of Manchester, The Mill, Sackville Street, Manchester, M13 9PL, UK.
Water Res. 2019 Apr 15;153:63-79. doi: 10.1016/j.watres.2019.01.010. Epub 2019 Jan 19.
Within developing countries, wastewater treatment (WWT) has improved in recent years but remains a high priority sustainability challenge. Accordingly, life cycle assessment (LCA) studies have recently started to analyse the environmental impacts of WWT technologies on the specific context of less developed countries, mainly in China and India. This work presents a comprehensive review of this knowledge with the aim of critically analysing the main conclusions, gaps and challenges for future WWT-related LCAs in developing countries. The most commonly assessed technologies in the 43 reviewed articles are different variations of activated sludge and extensive treatments applied in decentralized systems; however, studies focused on advanced technologies or new sources of pollution (e.g. micropollutants) are still lacking. Goal and system boundaries are normally clearly defined, but significant stages for some technologies such as the construction and sludge management are frequently not included and functional units should be defined accordingly to specific conditions in developing countries. At the inventory level, a more concise description of sources and technical parameters would greatly improve the quality of the LCAs along with accountability of direct greenhouse gas emissions. Eutrophication and global warming are the two most commonly assessed impacts; however, the calculation of terrestrial ecotoxicity when the sludge is used for agricultural purposes, of water use and of the land use change impacts associated to extensive technologies should be encouraged. The estimation of more site-specific databases, characterization factors (especially for eutrophication) or normalization and weighting values combined with more affordable access to background databases and LCA software, would deeply increase the accuracy of WWT-related LCAs in developing countries. An increased usage of the uncertainty analysis should be encouraged to assess the influence of these gaps in the final interpretation of the results. The review finishes with a summary of the main challenges and research gaps identified and with specific guidelines for future researchers to avoid the most common shortcomings found in the reviewed studies.
在发展中国家，废水处理（WWT）近年来有所改善，但仍是一个高度优先的可持续性挑战。因此，生命周期评估（LCA）研究最近开始分析 WWT 技术在欠发达国家特定背景下的环境影响，主要在中国和印度。这项工作全面回顾了这方面的知识，旨在批判性地分析发展中国家与 WWT 相关的 LCA 的主要结论、差距和挑战。在 43 篇综述文章中，评估最多的技术是活性污泥的不同变体和在分散系统中应用的广泛处理；然而，仍缺乏针对先进技术或新污染源（如微污染物）的研究。目标和系统边界通常定义明确，但对于一些技术，如施工和污泥管理等重要阶段经常未被包括在内，因此应根据发展中国家的具体情况定义功能单位。在清单层面上，更简洁地描述来源和技术参数将极大地提高 LCA 的质量，并对直接温室气体排放的责任追究。富营养化和全球变暖是最常评估的影响；然而，当污泥用于农业目的时，应鼓励计算土地使用变化影响以及陆生生态毒性的影响，还应鼓励计算水的使用。结合更实惠的获取背景数据库和 LCA 软件，估算更多特定于地点的数据库、特征化因子（特别是富营养化）或标准化和权重值，将极大地提高发展中国家与 WWT 相关的 LCA 的准确性。应鼓励更多地使用不确定性分析来评估这些差距对最终结果解释的影响。审查最后总结了确定的主要挑战和研究差距，并为未来的研究人员提供了具体的指导方针，以避免在综述研究中发现的最常见的缺点。
