Infiltration and inflow in sewer systems: Identification and quantification in Greece

Infiltration and inflow (I/I) are known to be among the major problems in sewer systems. According to literature reviews, infiltration and inflow are often estimated as 100% of sewage flow, causing major malfunction both to the system and the wastewater treatment plan. In some countries proper regulation has been applied; however, in others research is still in progress. In this study, two pilot projects were conducted in Greece, in the cities of Ioannina and Karditsa. In the first phase of the project, infiltration and inflow conditions were identified for each city. A model was then developed for the quantification of I/I. Last, the reliability of the model was validated and the components of sewage were analyzed. The general conclusion is that the quantity of I/I is significant, exceeding the typical assumptions in the design studies of sewer networks in Greece.