Urban wastewater [chapter 11]

International audienceThe quality of urban wastewater is variable with time and along the sewage network. In some cases when rain water is not collected separately, wastewater dilution may occur during wet periods. All these variation factors have an impact on the wastewater composition and particularly on organic matter and particulate fraction. Considering that a lot of substances present in urban wastewater are absorbing in the UV–visible range, several methods can provide useful information on the qualitative evolution of wastewater and on quantitative estimation of parameters, among which is UV–visible spectrophotometry. The efficiency of treatment processes of organic and particulate pollution removal can also be monitored from the examination of UV–visible spectra. Finally, a classification of urban wastewater can be proposed from the examination of spectral shape