Department of Public Works Engineering, Faculty of Engineering, Mansoura University, Mansoura 35516, Egypt.
Department of Public Works Engineering, Faculty of Engineering, Mansoura University, Mansoura 35516, Egypt.
Sci Total Environ. 2019 Apr 10;660:57-68. doi: 10.1016/j.scitotenv.2018.12.386. Epub 2019 Jan 3.
Most of wastewater treatment plants (WWTPs) in developing countries comprised primary and secondary treatment without including any tertiary treatment or sludge processing. Decision makers think that additional treatment is costly and the gained environmental benefits are limited. This study aims to investigate the environmental and economic benefits of improving current conventional WWTPs in developing countries by adding tertiary treatment and/or anaerobic digestion of sludge. For this purpose, life cycle assessment (LCA) for four different scenarios was studied for a wastewater plant located in Gamasa, Egypt. The 1st scenario is the plant in its current state. The 2nd scenario is the addition of anaerobic digestion of sludge. The 3rd scenario is the addition of a tertiary treatment stage. The 4th scenario is the addition of anaerobic digestion of sludge and tertiary treatment stage. CML 2000 method was used for assessing the environmental impacts of the four scenarios. The 4th scenario attained maximum environmental benefits for all categories due to the energy saving and the prospect of water reuse. The application of the 4th scenario achieved environmental benefits in some important categories such as ozone layer depletion. According to the economic evaluation, the addition of tertiary treatment leads to gain financial profits due to the value of the reusable produced water. This study underlines the importance of considering LCA in development of WWTPs in developing countries.
大多数发展中国家的污水处理厂（WWTP）仅包括一级和二级处理，而不包括任何三级处理或污泥处理。决策者认为，额外的处理费用高昂，且所获得的环境效益有限。本研究旨在通过增加三级处理和/或污泥厌氧消化来调查改善发展中国家现有常规 WWTP 的环境和经济效益。为此，针对位于埃及 Gamasa 的一家污水处理厂，研究了四种不同方案的生命周期评估（LCA）。第 1 种方案是工厂的现有状态。第 2 种方案是添加污泥厌氧消化。第 3 种方案是添加三级处理阶段。第 4 种方案是添加污泥厌氧消化和三级处理阶段。使用 CML 2000 方法评估了这四种方案的环境影响。由于节能和水再利用的前景，第 4 种方案在所有类别中均获得了最大的环境效益。第 4 种方案在一些重要类别（如臭氧层消耗）中实现了环境效益。根据经济评估，由于可再利用生产水的价值，添加三级处理可带来财务利润。本研究强调了在发展中国家开发 WWTP 时考虑生命周期评估的重要性。
