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This article provides an analytical model to determine the suitable location of pumping well located between two polluted parallel sources. The first source is assumed to be a polluted river, while the second one is an arbitrary contaminant source such as landfill leachate site or wastewater. The location of the well is specified so that it gets the highest amount of river water that satisfies water quality requirements. To validate the model results, a numerical simulation is conducted using MODFLOW to calculate the concentration of contaminants at various locations determined by the proposed analytical model. The results confirmed the suitability of the analytical model to determine the location of pumping well. Additionally, it is found that any increase in pumping time, pumping rate or initial contaminant concentration increases the distance between river and well. [ABSTRACT FROM AUTHOR]

To understand the isothermal flow of the non-Newtonian fluids through a porous media, it is necessary to know how shear stress affects fluid viscosity. The objective of this research is to investigate MHD non-Newtonian fluid flow that best fits the Powell-Eyring model in the presence of shear stress on an inclined porous plate for both lift and draining flow. The flow behaviour has been examined under the influence of a magnetic field and a shear distribution. In order to solve the non-dimensionalized governing equation, the Adomian Decomposition Method (ADM) is utilized. For both lifting and drainage flow, the influence of material parameters such as permeabi lity, shear stress, and magnetic has been investigated and described. The physical interpretation of the essential factors which influenced the shear stress versus the velocity is presented. Finally, the analysis highlights the impact of permeabi lity and magnetic parameters on the fluid flow graphically. The outcomes demonstrate that shear stress is an increasing function of fluid parameter in lifting case, but it is decreasing in drainage case. Moreover, the inclination is an important factor that affects the shear stress of both lifting and drainage flow. [ABSTRACT FROM AUTHOR]

Analytical studies for well design adjacent to river banks are the most significant practical task in cases involving the efficiency of riverbank filtration systems. In times when high pollution of river water is joined with increasing water demand, it is necessary to design pumping wells near the river that provide acceptable amounts of river water with minimum contaminant concentrations. This will guarantee the quality and safety of drinking water supplies. This article develops an analytical solution based on the Green's function approach to solve an inverse problem: based on the required level of contaminant concentration and planned pumping time period, the shortest distance to the riverbank that has the maximum percentage of river water is determined. This model is developed in a confined and homogenous aquifer that is partially penetrated by the stream due to the existence of clogging layers. Initially, the analytical results obtained at different pumping times, rates and with different values of initial concentration are checked numerically using the MODFLOW software. Generally, the distance results obtained from the proposed model are acceptable. Then, the model is validated by data related to two pumping wells located at the first riverbank filtration pilot project conducted in Malaysia. Article impact statement: The best well location from riverbank was determined analytically, achieving maximum amount of river water with minimum contaminant level. [ABSTRACT FROM AUTHOR]

Struvite is an eco-friendly fertilizer widely produced from waste streams. Landfill leachate, rich in ammonium-nitrogen (NH4-N), encourages the recovery of NH4-N in the form of struvite. However, the presence of heavy metals, particularly cadmium (Cd) and nickel (Ni), may affect the purity of struvite crystals, thereby hindering its applicability as a fertilizer. While previous studies have examined the effects of various heavy metals on struvite crystallization, the specific impact of Cd and Ni, especially in landfill leachate, remains insufficiently studied. This study aimed to fill this gap by investigating the effect of Cd and Ni on the purity and morphology of struvite crystals obtained from synthetic solutions (Phase 1) and synthetic landfill leachate (Phase 2). Additionally, a kinetics study was conducted to determine the fate of Ni and Cd during struvite crystallization. Batch experiments of struvite precipitation were performed with varying concentrations of Cd and Ni. Aqueous analysis results indicated a minor reduction in NH4-N recovery in both phases when Cd or Ni were present. Furthermore, XRD and SEM analyses of solid samples demonstrated that all crystals were highly pure struvite. The impact of Cd and Ni in Phase 2 was slightly more significant than in Phase 1. The kinetics study suggested that struvite can be safely recovered from landfill leachate contaminated with Cd and Ni. However, further research is needed on actual landfill leachate to fully understand the combined and advanced effects of heavy metals on struvite crystallization. [ABSTRACT FROM AUTHOR]