A case study of rainfall-derived infiltration and inflow of a separate sanitary sewer system

Abstract

Rainfall-deriver infiltration and inflow (RDII) can interfere with the performance of domestic wastewater drainage systems. It is also a major cause for the deterioration of the functional performance of those drainage systems and for the occurrence of untreated discharges of domestic wastewater to the water environment. In most cases, the actual size and location of these inflows are unknown. To assess this subject of the RDII, it is required to hold a detailed knowledge of the network and to do the diagnosis of the main problems, namely, the type of inflows, the magnitude of its occurrence and the places where the impacts are most relevant. This paper presents the application of an estimation methodology of RDII to a Portuguese case study.