Combined sewer overflows (CSOs) occur when flows exceed the hydraulic capacity of either the wastewater treatment plant (WWTP) or the collection system that transports the combined flow of storm water and sanitary sewage to the WWTP. When an overflow occurs, the excess flows tend to be discharged into a receiving body of water. CSOs typically discharge a variable mixture of raw sewage, industri...

Inflow/infiltration (I/I) and infiltration/exfiltration (I/E) are interactive processes which dynamically affect sewer and groundwater performance. The incidence and condition of "critical" sewers in the UK are identified together with methods of quantifying I/I and I/E as well as their impact on wet weather sewer performance and on urban groundwater pollution. Whilst the impacts of sewer trenc...

Separate sanitary sewer systems are designed to convey sewage waste from municipal areas to a central treatment facility; they are not designed to handle water associated with precipitation events. However, intercept of groundwater (infiltration) and of flows through manholes or unauthorized connections (inflows) introduces rainwater into the sanitary sewer system. Infiltration/Inflow (I/I) inc...

INTRODUCTION 4 This subject, Urban Wet-Weather Flows, was comprised of three basic subareas – combined-sewer 5 overflows (CSOs), sanitary-sewer overflows (SSOs), and stormwater discharges. Major proceedings 6 related to wet-weather flow (WWF) published during 2000 were the following: (1) ASCE EWRI 7 Conference – Bridging the Gap: Meeting the World’s Water and Environmental Resources Challenges ...

The Community strategy against pollution of surface water control policy was set out by the European Water Framework Directive 2000/60/EC which lays down new procedures for the identification of substances and development of control measures. After the decision n° 2455/2001/EC of the European Parliament and of the Council of 20 November 2001 setting out the first list of 33 substances or groups...

Model-based evaluation of real time control and model predictive strategies is often performed by estimating the yearly reduction in combined sewer overflow (CSO) volumes. This requires suf...

The formation and fate of sulfide in a force main and a downstream-located gravity sewer were investigated in an extensive field study. Sulfide formation in the force main was significant. However, during 14 minutes of transport in the gravity sewer, the sulfide concentration decreased 30%, on average. An application of a conceptual sewer process model for simulating the formation and fate of s...

This paper presents the results of a study conducted on the treatment of combined sewer overflows using ferrate (VI) [Fe (VI)]. At a Fe (VI) dose of 0.24 mg/L, total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), total biochemical oxygen demand (TBOD5), soluble biochemical oxygen demand (SBOD5), total suspended solids (TSS), volatile suspended solids (VSS), total phosphor...

Sewer systems are large-scale systems that collect and transport stormwater and sanitary sewage out of urban areas. Sewer systems are mainly operated using pumping stations and pollutants are removed from sewage by treatment plants before water is released into the environment. When a sewer overflow occurs, e.g., caused by a strong rainfall, sewage is discharged directly into the environment wi...