Spatial evolution of the characteristics of urban wastewater in combined sewers

摘要

An experimental on-site observatory of urban pollutant loads in combined sewers was created in the centre of Paris to quantify and characterise the dry and wet weather flow depending on spatial scale. Dry weather flow was monitored for seven days at the outlet of the six nested urban catchments and was analysed for suspended solids, organic matter, nitrogen and heavy metals. Results show a relative stability of pollutant loads of SS, organic matter and nitrogen, and important variations of heavy metals loads from one site to another. Most part of the pollutants were transported in particulate form. At last, an increase for organic matter and nitrogen loads appeared between the sampling sites situated at the upstream and the middle of the catchment area of study. Results obtained by dry weather, will be used as reference for the characterisation of wet weather flow pollution.