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Li D.,South China University of Technology | Wan J.,South China University of Technology | Wan J.,Key Laboratory of Pollution Control and Ecosystem Restoration Industry Clusters | Ma Y.,South China University of Technology | And 3 more authors.
PLoS ONE | Year: 2015

Fast urbanization and industrialization in developing countries result in significant stormwater runoff pollution, due to drastic changes in land-use, from rural to urban. A three-year study on the stormwater runoff pollutant loading distributions of industrial, parking lot and mixed commercial and residential catchments was conducted in the Tongsha reservoir watershed of Dongguan city, a typical, rapidly industrialized urban area in China. This study presents the changes in concentration during rainfall events, event mean concentrations (EMCs) and event pollution loads per unit area (EPLs). The first flush criterion, namely the mass first flush ratio (MFFn ), was used to identify the first flush effects. The impacts of rainfall and catchment characterization on EMCs and pollutant loads percentage transported by the first 40% of runoff volume (FF40) were evaluated. The results indicated that the pollutant wash-off process of runoff during the rainfall events has significant temporal and spatial variations. The mean rainfall intensity (I), the impervious rate (IMR) and max 5-min intensity (Imax5) are the critical parameters of EMCs , while Imax5, antecedent dry days (ADD ) and rainfall depth (RD) are the critical parameters of FF40. Intercepting the first 40% of runoff volume can remove 55% of TSS load, 53% of COD load, 58% of TN load, and 61% of TP load, respectively, according to all the storm events. These results may be helpful in mitigating stormwater runoff pollution for many other urban areas in developing countries. © 2015 Li et al. Source

Guo X.,South China University of Technology | Yang C.,South China University of Technology | Yang C.,Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control | Dang Z.,South China University of Technology | And 4 more authors.
Chemical Engineering Journal | Year: 2013

In order to understand the sorption processes of tylosin (TYL) and sulfamethazine (SMT) on soils, the sorption thermodynamics and kinetics properties of two chemicals on goethite were investigated through sorption equilibrium and sorption rate experiments. The results showed that the sorption of TYL and SMT were nonlinear and the sorption capacities were influenced by the pH conditions of solution. The sorption rates for TYL and SMT decreased as the initial concentration increased. The sorption process might be constituted with the initial boundary layer diffusion or external surface, then the intraparticle diffusion or pore diffusion stage and finally equilibrium stage related with the sorption on the interior surface of sorbent. Thermodynamic calculations of sorption of TYL and SMT on goethite revealed that the sorption of TYL on goethite was exothermal and spontaneous and SMT was endothermic and spontaneous. The results indicated that the transportation abilities of TYL and SMT might be weak for the soils rich in iron oxide. The significant differences in the sorption behavior of two chemicals might be related with their physicochemical properties and suggested that the sorption mechanisms of TYL and SMT on goethite would be complicated and the domain sorption mechanism for each chemical at different pH conditions would be variable. It should be noted to assess the environmental risks of TYL and SMT. © 2013 Published by Elsevier B.V. Source

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