Springer Science and Business Media LLC

Side weir is used as a slot in the side wall of the main channel to direct excess water that is above the weir crest. Such structures are used in control of flow level in irrigation, drainage networks and urban sewage disposal systems. Furthermore, circular channels are pretty important because considerable length of sewage disposal and transmission pipeline system is made of circular channels. In this study, changes inflow free surface, turbulence and flow field passing through a circular channel along a side weir are simulated. This means that for modeling the variations in flow free surface and the flow field turbulence, the volume-of-fluid scheme and RNG k–ε turbulence model are used, respectively. In order to validate the accuracy of the numerical model, the flow free surface changes along the side weir, the discharge coefficient of side weir, discharge of side weir, Froude number at upstream of the side weir and specific energy are compared with the experimental measurements. Comparison of simulation results with the experimental measurements shows high accuracy of CFD model. In other words, the root-mean-square error percent and the mean absolute error for flow free surface are, respectively, obtained to be 0.554% and 0.547%. Moreover, average difference between the specific energy at upstream and downstream of the side weir is calculated about 2.1%. The main purpose of this simulation is gaining an understanding of behavior of the passing flow through circular channels with side weir for subcritical flow regime.

Deficiency of surface water resources in semi-arid area makes the groundwater the most preferred resource to assure population increased needs. In this research we are going to quantify the rate of groundwater recharge using new hybrid model tack in interest the annual rainfall and the average annual temperature and the geological characteristics of the area. This hybrid model was tested and calibrated using a chemical tracer method called Chloride mass balance method (CMB). This hybrid model is a combination between general hydrogeological model and a hydrological model. We have tested this model in an aquifer complex in the region of Djelfa (Algeria). Performance of this model was verified by five criteria [Nash, mean absolute error (MAE), Root mean square error (RMSE), the coefficient of determination and the arithmetic mean error (AME)]. These new approximations facilitate the groundwater management in semi-arid areas; this model is a perfection and amelioration of the model developed by Chibane et al. This model gives a very interesting result, with low uncertainty. A new recharge class diagram was established by our model to get rapidly and quickly the groundwater recharge value for any area in semi-arid region, using temperature and rainfall.

This study investigated the removal of metal ions pollutants in mining wastewater such as Mn (II), Fe (III), Pb (II) and Cu (II) ions by acid-activated kaolinite clay (AAC) and titanium (IV) oxide (TiO2) nanoparticles supported on the AAC (TiO2–AAC). TiO2 nanoparticles were synthesised using titanium salt precursor with leaves extract of Parkia biglobossa and impregnated on the AAC to develop TiO2-AAC as a nanoadsorbent. The AAC and TiO2–AAC nanocomposites were characterized using different analytical techniques. Actual concentrations of selected heavy metals in mining wastewater was determined prior and after treatment using the prepared adsorbents in batch adsorptive studies with atomic absorption spectrophometer. The characterisation studies confirmed that a rutile phase TiO2 was doped the on acid-activated kaolinite clay. Morphology analysis shows that the developed adsorbents were homogeneously dispersed and porous. The results of the surface area further revealed that the AAC, TiO2 and TiO2–AAC has 14.15, 10.23 and 32.98 m2/g, respectively. The percentage removal of heavy metals followed the order of TiO2–AAC > AAC due to the higher surface area and enhanced surface functionality of the former than the latter. The adsorption capacity increased from 86.13 to 91.99% (Fe (III)), 83.12 to 89.37% (Mn (II)), 68.48 to 81.95% (Cu (II)) and 29.49 to 32.39% (Pb (II)) from AAC to TiO2–AAC. The kinetic and isotherm models were best fitted by pseudo-second-order kinetics and Langmuir model. Whilst the thermodynamic investigation found that, the adsorption process was endothermic, spontaneous and chemisorption controlled. Conclusively, the TiO2–AAC nanocomposite exhibited better performance than AAC alone.

With the increasing demands for water due to growing population, urban expansion, agricultural development and groundwater resources are gaining much attention, particularly in Gopiballavpur block, Paschim Medinipur district (West Bengal, India). Present study used cohesive approach of remote sensing and geographic information system to deliver an appropriate platform for convergent study of multi-disciplinary data and decision building for artificial groundwater recharge. Thematic maps were generated from Landsat8-Operational land Imager (OLI) and Shuttle Radar Topographic Mission (SRTM), and aquifer parameter thematic layers were organized from conventional field data. The weighted linear combination method was used to determine the weights of various themes and their classes, namely ‘very good’, ‘good’, ‘poor’ and ‘very poor’ for identifying recharge potential zone. It has been concluded that 14.58% area has very good groundwater recharge potentiality of the study area. The area having ‘good’, ‘moderate’ and ‘low’ recharge potential is about 32.77%, 39.67% and 12.98%, respectively.

The escalating concern over the presence and health implications of potentially toxic elements (PTEs) in drinking water has underscored the need for rigorous risk assessments. Our study aimed to quantify both the non-carcinogenic and carcinogenic health risks associated with exposure to selected PTEs—namely arsenic (As), chromium (Cr), and cadmium (Cd). Also, we evaluated ingestion and skin contact exposures to risks during summer and winter using metrics such as the hazard quotient (HQ), hazard index (HI), and cancer risk (CR) for children, adult males, and adult females. For all demographic groups and exposure pathways, the HQ values remain below the established safety threshold (HQ < 1). Notably, As consistently had the highest average HI value across children, male adults, and female adults. Seasonal variations were statistically significant (p < 0.05) for As and Cr, but not Cd. During the summer, the average total carcinogenic risks (TCR) from drinking water exposure were 7.61 × 10–6, 8.94 × 10–6, and 1.12 × 10–5 for children, male adults, and female adults, respectively. In the winter, these values were 1.18 × 10–5, 1.40 × 10–5, and 1.75 × 10–5, respectively. The fuzzy C-means clustering analysis provided insights into our dataset's Cr, Cd, and As distribution patterns. Results indicate that As, Cr, and Cd mean concentrations were below the World Health Organization health-based guidelines. The CR values for children and adults from drinking water exposure were slightly above or below the US Environmental Protection Agency’s standards. These findings can inform research and policy-making regarding the risk of PTEs in drinking water and highlight the need to monitor Shiraz water regularly.

This study aims to follow the photodynamic and spectroscopic properties of dianionic rose Bengal disodium salt (RB) on Staphylococus aureus (S. aureus) in phosphate buffer solution (PBS) at pH 7.3. It focused on: (1) the effect of several reactive oxygen species (ROS) antioxidants used [such as sodium azide (NaN3), l-tryptophan (l-Trp) and d-mannitol] on the RB photodynamic efficiency as a mean to identify the main ROS attributed, and (2) the possible interactions of the RB with the important singlet oxygen quencher used namely tryptophan and/or between the dye and the bacteria S. aureus thanks to a spectroscopic study. The results showed that 20 µM of RB and 10 min of visible light (50 mW/cm2) with a light fluence dose of 30 J/cm2 are crucial for a good photodynamic action, achieving a reduction of 79.4% in the viability. Rose Bengal photodynamic action was in part inhibited by D-mannitol and l-Trp, indicating the mediation by.OH and 1O2, respectively. The high inhibition of the RB activity against S. aureus by l-Trp is not due only to its singlet oxygen quencher ability but it is mainly due to the interaction between RB and l-Trp as shown spectrophotometrically.

Uranium (U) is formed by the interaction of groundwater in aquifer and the surrounding rocks. The area chosen for this study is a hard rock terrain of various lithology in South India, which releases U in groundwater and affect the groundwater quality. Hence, this study was conducted to understand the geochemistry and temporal variations of U in groundwater with respect to saturation state of minerals for different seasons namely Pre-monsoon (PRM), Northeast monsoon (NEM), Southwest monsoon (SWM) and Post-monsoon (POM). A total of 216 groundwater samples were collected, representing various lithology (Fissile hornblende biotite gneiss, Charnockite, Quartzite, Granite and Flood Plain Alluvium) in the study area. The collected samples were analyzed for physical parameters such as Electrical conductivity, Total dissolved solids, pH and major ions. U was measured using Laser Fluorimeter. The study infers that weathering in SWM, ion exchange in PRM and POM and anthropogenic process in NEM were the three major processes that could dominate the hydrogeochemistry of U. The higher concentration of U has been highlighted, and the water–rock interaction has been studied to know the sources of origin and it has been plotted through bivariate and ternary diagrams. The saturation index study was made and calculated for uranium, carbonate, sulfate, silicate and phosphate minerals using PHREEQC Programme. Uraninite and Coffinite are the dominant saturated states of U minerals which tend to attain near saturation to saturation state irrespective of seasons. With the increase in U concentration irrespective of seasons, it was noticed that the saturation state of minerals is also increasing. Overall, the weathering process and the lithological impact are the sources for higher concentration of U and their minerals occurring in the study area. The outcome of the study will help the policy makers for sustainable management to safeguard the groundwater resource in this region.