Unit of Environmental Engineering, University of Innsbruck, Technikerstr. 13, 6020 Innsbruck, Austria.
Water Sci Technol. 2013;67(7):1574-80. doi: 10.2166/wst.2013.029.
The technical design of urban drainage systems comprises two major aspects: first, the spatial layout of the sewer system and second, the pipe-sizing process. Usually, engineers determine the spatial layout of the sewer network manually, taking into account physical features and future planning scenarios. Before the pipe-sizing process starts, it is important to determine locations of possible weirs and combined sewer overflows (CSOs) based on, e.g. distance to receiving water bodies or to a wastewater treatment plant and available space for storage units. However, positions of CSOs are also determined by topological characteristics of the sewer networks. In order to better understand the impact of placement choices for CSOs and storage units in new systems, this work aims to determine case unspecific, general rules. Therefore, based on numerous, stochastically generated virtual alpine sewer systems of different sizes it is investigated how choices for placement of CSOs and storage units have an impact on the pipe-sizing process (hence, also on investment costs) and on technical performance (CSO efficiency and flooding). To describe the impact of the topological positions of these elements in the sewer networks, graph characteristics are used. With an evaluation of 2,000 different alpine combined sewer systems, it was found that, as expected, with CSOs at more downstream positions in the network, greater construction costs and better performance regarding CSO efficiency result. At a specific point (i.e. topological network position), no significant difference (further increase) in construction costs can be identified. Contrarily, the flooding efficiency increases with more upstream positions of the CSOs. Therefore, CSO and flooding efficiency are in a trade-off conflict and a compromise is required.
一是排水管网的空间布局，二是管道尺寸设计。通常，工程师会根据物理特征和未来规划场景手动确定排水管网的空间布局。在开始管道尺寸设计之前，根据例如与受纳水体或污水处理厂的距离以及存储单元的可用空间等因素，确定可能的堰和合流污水溢流（CSO）的位置是很重要的。然而，CSO 的位置也由排水管网的拓扑特征决定。为了更好地理解新系统中 CSO 和存储单元位置选择对系统的影响，本工作旨在确定特定案例以外的一般规则。因此，基于大量不同大小的随机生成的阿尔卑斯山排水系统，研究了 CSO 和存储单元的位置选择如何对管道尺寸设计（因此也对投资成本）和技术性能（CSO 效率和洪水）产生影响。为了描述这些元素在排水管网中的拓扑位置的影响，使用了图特征。通过对 2000 个不同的阿尔卑斯山合流污水系统进行评估，发现与预期一致的是，随着网络中 CSO 位置越靠后，建设成本越高，CSO 效率越高。在特定位置（即拓扑网络位置），建设成本没有明显差异（进一步增加）。相反，CSO 位置越靠前，洪水效率越高。因此，CSO 和洪水效率之间存在权衡冲突，需要进行妥协。
