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This paper aims to propose methods to mitigate the risks of flash flood events in arid rural communities with poor infrastructure. A flash flood management case study was conducted at Afouna Village in Egypt, which is characterized by an arid climate and faced a devasting flash flood in 2015. First, the flash flood was modelled and it was found that it corresponds to a 100 year return period flood that led to an almost 13 million m3 total runoff volume. A structural protection approach, using an artificial infiltration pond, was applied to mitigate the flooding risks through water harvesting and recharging the groundwater of the Moghra aquifer. In this study, a novel approach was proposed, which is substituting the low permeability silty sand (2.0 × 10−4 m/s) in the pond area with a high permeability one (9.6 × 10−3 m/s), which will enhance water harvesting and reduce direct evaporation. Modern techniques of hydrological modelling were utilized in order to achieve the optimal use, and harvesting, of flash flood water.

This work highlights the potential of corncob biochar (CCBC) and Brevibacillus parabrevis for the decolorization of brilliant green (BG) dye from synthetically prepared contaminated wastewater. The CCBC was characterized by proximate, Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller analysis, respectively. Different parameters affecting the adsorption process were evaluated. The experimental results were analyzed by the Langmuir and Freundlich isotherm models. Kinetic results were examined by different models; pseudo-second-order model has shown the best fit to the experimental data. Anew positive values of ΔH o (172.58 kJ/mol) and ΔS o (569.97 J/K/mol) in the temperature range of 303-318 K revealed that the adsorption process was spontaneous and endothermic. The present investigation showed that the bacteria immobilized with CCBC showed better BG dye degradation. The kinetic parameters, μ max , Ks, and μ max , were found to be 0.5 per day, 39.4 mg/day, and 0.012 L/ mg/day using Monod model, respectively. The adsorbent with bacteria showed good potential for the removal of cationic BG dye and can be considered for the remediation of industrial effluent.

This study aims to provide the technoeconomic aspects of two clean processes for biodiesel production. The first process utilizes waste cooking oil as a feedstock and potassium hydroxide as a homogeneous catalyst. The second process uses cement kiln dust heterogeneous catalyst and virgin soybean oil. A comparison was performed between the results of the technical and economic assessments to determine the more feasible process. Theoretical purities of biodiesel and glycerol obtained upon conducting the simulation of both processes are high, i.e., 99.99%. However, the homogeneous process is economically superior as its payback period is slightly more than 1 year while the return on investment is higher than 74%, and the unit production cost is USD 1.067/kg biodiesel. Sensitivity analysis revealed that the profitability of biodiesel production is very sensitive to the feedstock price and recommends shifting toward waste vegetable oils as a cheap feedstock to have a feasible and economic process.