Department of Civil Engineering, University of Coimbra, Portugal.
Department of Civil Engineering, University of Coimbra, Portugal.
Sci Total Environ. 2018 Jan 15;612:1042-1057. doi: 10.1016/j.scitotenv.2017.08.315. Epub 2017 Sep 7.
In the field of rehabilitation of separate sanitary sewer systems, a large number of technical, environmental, and economic aspects are often relevant in the decision-making process, which may be modelled as a multi-objective optimization problem. Examples are those related with the operation and assessment of networks, optimization of structural, hydraulic, sanitary, and environmental performance, rehabilitation programmes, and execution works. In particular, the cost of investment, operation and maintenance needed to reduce or eliminate Infiltration from the underground water table and Inflows of storm water surface runoff (I/I) using rehabilitation techniques or related methods can be significantly lower than the cost of transporting and treating these flows throughout the lifespan of the systems or period studied. This paper presents a comprehensive I/I cost-benefit approach for rehabilitation that explicitly considers all elements of the systems and shows how the approximation is incorporated as an objective function in a general evolutionary multi-objective optimization model. It takes into account network performance and wastewater treatment costs, average values of several input variables, and rates that can reflect the adoption of different predictable or limiting scenarios. The approach can be used as a practical and fast tool to support decision-making in sewer network rehabilitation in any phase of a project. The fundamental aspects, modelling, implementation details and preliminary results of a two-objective optimization rehabilitation model using a genetic algorithm, with a second objective function related to the structural condition of the network and the service failure risk, are presented. The basic approach is applied to three real world cases studies of sanitary sewerage systems in Coimbra and the results show the simplicity, suitability, effectiveness, and usefulness of the approximation implemented and of the objective function proposed.
在独立污水下水道系统的修复领域，决策过程中通常涉及大量技术、环境和经济方面的问题，可以将其建模为多目标优化问题。例如，与网络的运行和评估、结构、水力、卫生和环境性能的优化、修复计划以及执行工程相关的问题。特别是，使用修复技术或相关方法减少或消除地下水位渗入和雨水地表径流（I/I）所需的投资、运营和维护成本，可能远低于在系统或研究期间输送和处理这些流量的成本。本文提出了一种全面的 I/I 成本效益修复方法，该方法明确考虑了系统的所有要素，并展示了如何将逼近作为一个目标函数纳入一般进化多目标优化模型。它考虑了网络性能和废水处理成本、几个输入变量的平均值，以及可以反映采用不同可预测或限制情景的速率。该方法可用作支持项目任何阶段下水道网络修复决策的实用快速工具。本文介绍了一种使用遗传算法的双目标优化修复模型的基本方面、建模、实施细节和初步结果，该模型的第二个目标函数与网络的结构状况和服务故障风险有关。基本方法应用于科英布拉的三个实际卫生下水道系统案例研究，结果表明所实施的逼近和所提出的目标函数的简单性、适用性、有效性和有用性。
