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Published on: May 15, 2017
Infiltration and inflow in combined sewer systems: long-term analysis
G Weiss1, H Brombach, B Haller
1Umwelt- und Fluid-Technik Dr. H. Brombach GmbH, Bad Mergentheim, Germany. uft@uft.mayn.de
Summary
Reducing infiltration and inflow (I/I) in combined sewer systems significantly improves stormwater treatment performance. This study highlights I/I as a major bottleneck, often underestimated in urban hydrology management.
Area of Science:
- Urban Hydrology
- Wastewater Engineering
- Environmental Science
Background:
- Combined sewer systems face challenges in stormwater treatment due to hidden reserves and bottlenecks.
- Undesired infiltration and inflow (I/I) of non-polluted water is a significant, underestimated issue in drainage systems.
- I/I negatively impacts the performance of sewer systems, despite the inflowing water being non-polluted.
Purpose of the Study:
- To identify hidden reserves and bottlenecks in stormwater treatment within German combined sewer systems.
- To provide insights into water pathways in urban hydrology.
- To emphasize the impact of infiltration and inflow (I/I) on drainage system performance.
Main Methods:
- Analysis of 34 German combined sewer systems, including combined sewer overflow (CSO) tanks and treatment plants.
- Focus on quantifying and understanding the phenomenon of infiltration and inflow (I/I).
Main Results:
- Infiltration and inflow (I/I) is a major, underestimated factor affecting the performance of combined sewer systems.
- Reducing I/I can substantially improve pollution control in existing combined systems.
- Artificial infiltration of surface runoff may exacerbate I/I issues.
Conclusions:
- Effective management of infiltration and inflow (I/I) is crucial for optimizing stormwater treatment in urban areas.
- Reducing I/I offers comparable benefits to separate drainage systems for pollution control.
- Further research and practical strategies are needed to mitigate I/I in combined sewer networks.
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