Author(s): Francesco De Paola; Antonio Ranucci
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Keywords: No Keywords
Abstract: Urban runoff discharges in water receivers, during a rainfall, are a significant pollution source especially after a long antecedent dry period. Structural facilities that, most commonly, are used in an urban drainage system to reduce first flush pollution are detention and storage tanks. In this paper, many numerical simulations, related to many rain gauges located in Italy, are reported with reference to a typical Italian urban catchment. For each station where a rain gauge is installed, as the tank volume changes, the pollution load removal rate and the percentage of runoff volume discharged into receiver were estimated. In particular, calculations to generate incoming hydrographs and pollutographs are made using SWMM (Storm Water Management Model) by E. P. A. (Environmental Protection Agency); afterwards other simulations let to analyze the operation of different configurations of the sewer system (stormwater or combined) with a capture tank, to estimate the effectiveness and efficiency of such device. All simulations show that rainfall dependency is generally negligible; capture tanks let to great pollution reduction in receivers than other devices. Afterwards, an approach is proposed to easy valuate the average pollution reduction when adopting stormwater capture tanks and obtained simplified formulas can be used to design these devices in Campania, Piemonte and Umbria Regions, since design criteria seem not completely consolidated in the literature.
Year: 2010