Innovative monitoring of combined sewer overflow (CSO) quality in the Liguori catchnment (Cosenza, Italy)

Estimates of urban wet-weather flow pollutant loads are required to assess their impact on receiving waters and optimize wastewater treatment plant (WWTP) and combined sewer overflow (CSO) operations. In particular, a quantitative characterization of flow quality by means of fairly accurate monitoring is required for developing a rational planning approach and preferential treatment strategies. The main aim of this paper is to examine the qualitative–quantitative characteristics of wet-weather flow in an urbanized test catchment in Cosenza, Italy, and to compare three studied water quality constituent concentrations (total suspended solids (TSS), total chemical oxygen demand (COD_t) and filtered chemical oxygen demand (COD_f)) obtained by laboratory analyses to those measured by a UV/Vis spectrometer (‘spectrolyzer scan’), which represents a most modern and efficient spectrometric instrument requiring little maintenance. The results of such comparisons indicated the feasibility of using in situ spectroscopy to provide fairly accurate concentrations of the constituents studied, particularly in the case of COD_t and COD_f.