The purpose of this study is to find the value of the discharge coefficient (Cd) on a sieve with a circular perforated plate so that it can be used for application in the field. The method used is to make a physical model test of the screen weir in the laboratory with a width of 40 cm and a length of 797 cm, then the screen is made variations in the diameter of the hole 6, 8, 10 and 12 mm, flowrate Q = 453–4 481 cm3∙s–1 and the slope of the screen θ = 20–45°. The result was quite ef-fective, the sediment did not enter above the screen and did not clog the screen even the catch was quite good about 80% of the screen rods. The discharge coefficient (Cd) is directly proportional to the square value of the number Froude (Fr), the slope of the screen (θ) and the ratio of distance, diameter of the screen (a:d) and inversely proportional to the value of the specific energy square (E). From modelling the average value of the discharge coefficient (Cd) between 0.1–2.75 with NSE = 0.71, MAE = 0 and RMSE = 0.12.

A new composite adsorbent was prepared by modifying low cost local adsorbent (LCL) using MgFe layered double hydroxide (LDH). This low cost local adsorbent was also prepared from the activation of date palm leaf derived from agricultural waste. In comparison to the low LCL, the adsorption capacity of the new composite adsorbent (LCL/MgFe-LDH) was improved. This was measured in terms of its ability to remove lead from wastewater. The Scanning electron microscope (SEM), Energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR) and the specific surface area by the (Brunauer, Emmett and Teller) theory (BET) tests were conducted for the characterisation of LCL and LCL/MgFe-LDH. The behaviour of the lead adsorption processes by using LCL/MgFe-LDH as adsorbent was investigated in batch experiments by examining different values of solution pH, contact time, adsorbent dose and initial Pb2+ concentration. High removal efficiency was exhibited by LCL/MgFe-LDH, a value almost double that of LCL. This was attributed to the increase in surface area of LCL/MgFe-LDH (79.7 m2·g–1) in contrast to the surface area of LCL (24.5 m2·g–1). The Freundlich equations and pseudo-second-order kinetics model were appropriate for the provision of adsorption equilibrium data for Pb2+ on adsorbents. These results reveal the great potential of the new composite adsorbent (LCL/MgFe-LDH) if applied to the absorption of heavy metal ions.