Identifying factors influencing infiltration and inflow (I/I-water) in wastewater systems using multivariate data analysis

Abstract

The share of infiltration and inflow water (I/I-water) in the wastewater network is influenced by several factors. The purpose of this study is to propose a method to investigate the relationship between different variables and the proportion of I/I-water in the wastewater network. The method tested is a multivariate modelling technique with which the following variables were examined; a) estimated water leakage from drinking water pipes, b) total volume of delivered drinking water, c) average age of the sewer pipes, d) renewed amounts of sewer pipes, e) system solution (share of combined system) and f) precipitation. The multivariate modelling analysis reveals different patterns in influencing factors. When using the proposed model it is possible to rank the variables included in the model and the optimal level of I/I-water should be determined after identifying the factors influencing the I/I-water. When aiming to remove I/I-water the most cost-efficient measures should be considered. These measures may vary according to context.