Methodology for the characterisation of heterogeneous fractions in wastewater.

A better knowledge of colloidal and particulate matter of urban wastewater is necessary for the optimisation of the wastewater treatment. This paper presents a methodology based on the study of each granular fraction (settleable, supracolloidal, colloidal and soluble matter) separated by different techniques of liquid-solid separation and analysed by non specific parameters (chemical oxygen demand, total suspended solids, UV spectra). The application of this methodology to a storm event allows to explain the quality variation observed during this period.