Impact of two pollutant fluxes calculation methods along with uncertainties on estimation of combined sewer overflow contribution to environmental pollution at the whole urban catchment scale

ABSTRACT

An event mean concentration database collected at the main combined sewer overflows (CSOs) of Bordeaux city was used to estimate pollutant fluxes emitted at CSOs using the Typical Concentration (TC) method. In addition, turbidity sensors were recently installed and used to study the contribution to environmental pollution in terms of total suspended solids (TSS) of each CSO. Comparison of these two different methods have shown a difference of 33% in the estimation of the total TSS mass emitted over eight months and a difference in uncertainty estimation (± 23.5% for TC method and ± 11.0% for the turbidity method). Analysis of CSO contributions have shown different rankings among the three main CSOs of this catchment depending on the method selected.

KEYWORDS:

• Turbidity
• Gaussian Kernel Density Estimation
• Automatic data validation

Acknowledgements

The authors want to thank Bordeaux Métropole and SGAC (Société de Gestion de l’Assainissement de Bordeaux Métropole) for their technical and financial support.

Disclosure statement

No potential conflict of interest was reported by the authors.