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Batch tests were conducted to know the effectiveness of using surfactants only and surfactants with a complexing agent to remove Cu (II) and Zn (II) from an artificially contaminated sandy soil. SDS (sodium dodecyl sulfate), AOT (alpha-olefin sulfonate) and Tx-100 (Triton X-100) were the surfactants selected as the washing liquids. Complexing agent EDTA (ethylenediaminetetraacetic acid) was also selected for washing the soil. To avoid external factors from interfering with the cleaning process, artificial soil formed by a mixture of clean sand and bentonite was used to form contaminated soil samples. The amount of organic matter present was insignificant. Compared to extraction by distilled water, tests indicated that a six-fold increase in copper extraction occurred due to the presence of surfactants and/or the complexing agent EDTA. Compared to extraction by distilled water, zinc extraction by surfactants and or the complexing agent EDTA was nearly 1.2 to 1.3 times more. Effects of competition as well as interference associated with the adsorption and desorption of these metals are also very briefly reported.

The sharp-crested weir in a rectangular open channel can be used as a simple and accurate device for flow measurement and control in open channels. However, in the past, the solution to this problem was found mainly on the basis of experimental data or through the development of simplified theoretical expressions. In the present study, k-ε turbulence model is applied to obtain the flow parameters such as pressure head distributions, velocity distributions, and water surface profiles. The predictions of the proposed numerical model are validated using existing experimental data. The k-ε turbulence model developed is used to predict the characteristics of a sharp-crested weir in a rectangular open channel. The volume of fluid (VOF) scheme is used to find the shape of the free surface. A properly validated model permits one to obtain the flow characteristics of the sharp-crested weir for a wide range of weir and hydraulic parameters without recourse to expensive and more time consuming experimental methods. Further, the model permits one to incorporate small changes in the geometric parameters involving small changes in inlet and outlet conditions and study their impact on the weir flow characteristics.

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