We investigated the leaching characteristics of bisphenol A (BPA) from two kinds of epoxy-resin pavement materials, one containing epoxy resins (EPs) and the other containing epoxy-acrylate resins (EPAs). Both samples contained residual BPA monomer, at levels of 9.0 mg g À1 for the EP resin sample and 4.4 mg g À1 for the EPA resin sample. These amounts were larger than amounts previously measured for polycarbonate samples. The amount of BPA leached from the samples increased with temperature. The leaching of BPA from EP was more strongly affected by temperature than the leaching from EPA. The pH also affected the amount of leached BPA. The maximum leached amount was observed under alkaline conditions (pH 10.8) for both sample types. The amounts of BPA that might leach from pavement materials during 1 h of heavy rain were estimated to be 0.9 mg m À2 for EP and 3.5 mg m À2 for EPA. Our results indicate that EPs disposed of in waste landfills without any treatment may be a source of BPA in leachate at landfill sites.
Heavy metals designatedin the PRTR Law are used for various purposes and widely dispersed in environment, and are feared to incur adverse effects on human health and ecosystem.The purpose of this study was to clarify the actual state of effluence of these heavy metals into water environment from overhead way through rainfalls, as well as their source and flow channels.It has been clarified that the effluence of road dust on overhead way into rivers through rainfalls burdens water environment with the load of heavy metals especially Mn, Co and Zn.Cr and Pb were found in paints for road markers, and Mn in asphalt in high concentrations. It has also been clarified that high concentrations of Zn is contained in tires. When Zn concentrations were high in the sediment at the outlet spots of wastewater from overhead way that contained much effluences, the concentrations of DPPD (N,N'-diphenyl p-phenylenediamine: an additive for a tire) tended to increase. These facts verify that the main sources of Zn in road dust are tires. Under the PRTR Law, the discharge from automobile exhaust gases and paints for road markers into environment are estimated, but the discharge of Zn from tires into environment should also be closely watched.
To achieve stable removal of BOD, nitrogen and phosphorus, UF membrane process was combined with intermittent aeration sequencing batch activated sludge process(SBR process). The effect of a hybrid system was studied comparing with that of a SBR system using bench scale plants.Removal efficiencies of BOD and T-N in a hybrid system were higher than those in a SBR system, whereas removal efficiency of T-P was similar in both systems. In order to diminish UF membrane facility in size, a quadruple reactor type hybrid system was developed and it was successfully applied.A hybrid system was able to keep high removal efficiencies when the bulking of activated sludge occured. The flux of UF membrane was recovered by washing with 0.1N NaOH and 10% H2O2 solutions.
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