Valentin's research was on cost and benefit of high-resolution in-sewer water quality monitoring.

The full understanding of the dynamics in flow and pollutant concentrations in combined sewer systems is an important issue for the management and design of these systems. However, the lack of water quality data in sufficient quality and resolution is often a critical aspect in sewer water quality modeling.

In Graz, Austria, a sewer online monitoring station has been operated at a combined sewer overflow since 2002, continuously measuring CODeq, T(D)OCeq and TSSeq concentrations at 1 minute intevals.

Based on the case study in Graz, the following topics were addressed:

(1)    Data management, analysis and validation;
(2)    Sewer water quality modelling based on high resolution data;
(3)    Coupling of the models with a state-of-the art framework allowing for sensitivity analysis and automated model calibration;
(4)    Evaluation of model performance.