| Popis: |
In recent years, various proprietary treatment technologies have evolved to reduce the polluting impact of urban run-off on receiving watercourses. The majority are \342\200\230flow-through\342\200\231 devices, designed to intercept and store pollutants in submerged chambers for later removal and safe disposal. Frequently, the performance of such systems is described solely in terms of \342\200\230ability to remove pollutants from the inflow\342\200\231, usually at specified discrete flowrates. However, it is suggested that this is insufficient to give a true assessment of performance and a critical parameter that is often overlooked is chamber \342\200\230retention efficiency\342\200\231, the ability of a chamber to retain stored pollutants once collected. In the current study, this parameter is investigated experimentally for a range of chamber configurations. Cylindrical chambers with different inlet orientations, internal components and hence flow dynamics are considered. The study identifies retention efficiency as being a major differentiator between designs, and concludes that chambers in which captured pollutants are stored in regions that are hydraulically isolated from the main treatment area are likely to be the most effective in practice. |
