Combined sewer overflows (CSOs) are of major environmental concern for impacted surface waterbodies. In the last decades, major storm events have become increasingly regular in some areas, and meteorological scenarios predict a further rise in their frequency. Consequently, control and treatment of CSOs with respect to best practice examples, innovative treatment solutions, and management of sewer systems are an inevitable necessity. As a result, the number of publications concerning quality, quantity, and type of treatments has recently increased. This review therefore aims to provide a critical overview on the effects, control, and treatment of CSOs in terms of impact on the environment and public health, strict measures addressed by regulations, and the various treatment alternatives including natural and compact treatments. Drawing together the previous studies, an innovative treatment and control guideline are also proposed for the better management practices.

The Implementation Plan (D2.1) is a document, which outlines how and where different digital solutions for water infrastructures will be demonstrated and assessed in the scope of WP2 of the DWC project. It is the first of three deliverables and followed by demonstration and assessment of performance and return of investment by means of key performance indicators (KPI) also defined in this deliverable. ; Version (v0.1.0) submitted to EC.