The presence of toxic cadmium ions in the wastewater resulted from industrial sector forms the critical issue for public health and ecosystem. This study determines the ability of four vertical ...subsurface flow constructed wetlands units in the treatment of simulated wastewater laden with cadmium ions. This was achieved through using sewage sludge byproduct as alternative for the traditional sand to be substrate for aforementioned units in order to satisfy the sustainable concepts; however, Canna indica and Typha domingensis can apply to enhance the cadmium removal. The performance of constructed wetlands has been evaluated through monitoring of the pH, dissolved oxygen (DO), temperature, and concentrations of cadmium (Cd) in the effluents for retention time (0.5–120 h) and metal concentration (5–40 mg/L). The results demonstrated that the Cd removal percentage was exceeded 82% beyond 5 days and for concentration of 5 mg/L; however, this percentage was decreased with smaller retention time and higher metal concentration. The Grau second-order kinetic model accurately simulated the measurements of effluent Cd concentrations as a function of retention times. The FT-IR analysis indicated the existence of certain functional groups capable of enhancing the Cd removal. The treated wastewater's pH, DO, temperature, total dissolved solids (TDS), and electrical conductivity (EC) all meet the requirements for irrigation water.
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•Using of sewage sludge byproduct as substrate in the constructed wetlands.•Application of sustainable (green) concepts by reusing of byproduct.•Reclamation of contaminated water for non-potable uses.•Sewage sludge alternative to the traditional sand substrate.•Mechanisms responsible of cadmium removal in the constructed wetlands.
The fate of cadmium at the Muharram Aisha wastewater treatment plant in Karbala governorate, Iraq was studied using the TOXCHEM model. Cadmium, a known carcinogen, and is considered one of the most ...dangerous heavy metals and high concentrations, greater than permissible limits, were found in the treated wastewater. The plant operates using an activated sludge system and this was modeled via TOXCHEM with a sensitivity analysis carried out on the extended aeration system. Prior to analysis, the model was calibrated and validated for cadmium, with the adjustments leading to a mean square error (RMSE) and correlation coefficient (R) of 0.0001 and 0.81, respectively. The mass balance of cadmium in the Muharram Aisha treatment plant was found to be 4832.44 g/day (37.1726%) in the treated wastewater and 8164.52 g/day (62.804%) in the sludge, which indicated that the mix liquor suspended solid (MLSS) was the most sensitive factor. The sensitivity to cadmium was analyzed via MLSS in the extended aeration system and the results o indicated that the higher the MLSS concentration (mg/L), the greater the removal of cadmium in the treated wastewater. It was found that increasing the MLSS through a biological treatment method reduced the concentration of cadmium without the need for additional of any (potentially harmful) chemical treatments. The plant was subsequently operated for a period of 5 months with the MLSS increased from 1500 to 4500 mg/L, and this reduced the concentration of cadmium in the wastewater from 0.36 to 0.01 mg/L as a consequence. This research demonstrates how the novel application of TOXCHEM can be a useful tool in the reduction of heavy metal contamination in the environment.
Earth dams are built for various reasons these including storage of water, regulation of water flow, prevention of flooding, and the generation of hydroelectric power. The drain pipes within an earth ...dam, are considered one of the more important control devices used to reduce the effects of problems caused by seepage. As such, the role of drain pipes against seepage problems in an earth dam, has been studied numerically in this investigation. The effects of drain pipe location and their diameters (50, 75, 100, and 150 mm), were examined using different hydraulic heads. The analysis focuses on the characteristics of relative seepage flow, exit gradient, and factor of safety regarding sliding. A range of models of typical earth dams, with and without drain pipes, have been simulated using Geo-Studio software in SEEP/W and SLOPE/W applications, examining more than 200 different cases. By using the data computed from numerical models, new formulas for predicting the seepage parameters and factors of safety were developed in this study by using the multiple non-linear regression (NLR) approaches. The findings show that the presence of a drain pipe reduces seepage flow and the exit gradient, at the same time increasing the factor of safety. Regarding pipe diameter, the rate of seepage and exit gradient decreased while the factor of safety increased as the diameter of the pipe increased. The factor of safety increased by between 11 and 25% when the drain pipe was placed in an optimal position, allowing for a reduction in seepage flow and exit gradient.
Estrogenic hormones, found as micropollutants in water systems, give rise to grave concerns for human health and marine ecosystems, triggering a cascade of adverse effects. This research presents an ...innovative manufacturing approach using nanoscale layered double hydroxides of magnesium and iron, with sodium dodecyl sulfate surfactant, to create highly efficient sorbent cement kiln dust (CKD) based beads (CKD/MgFe-SDS-LDH-beads). These beads effectively remove estrone from water. Optimization of the preparation process considered factors like molar Mg/Fe ratio, CKD dosage, pH, and SDS dosage using Response Surface Methodology (RSM). The adsorption process was well-characterized by Langmuir isotherm and pseudo-second-order kinetic models, demonstrating a remarkable 6.491 mg/g sorption capacity. Results proved that the calcite was the main component of the CKD with miners of dolomite, and quartz. Adsorption capacity, surface charges, and the availability of vacant sites may be the main mechanisms responsible of removal process. Experimental tests confirmed the beads' potential for estrone removal, aligning with the Bohart-Adams and Thomas-BDST models. This study introduces a promising, eco-friendly solution for addressing water contamination challenges.
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•Using cement kiln dust byproducts for preparation of novel sorbent.•Sorbent is prepared in the form of sodium alginate beads.•Beads are composed of kiln dust, magnesium, iron and surfactant.•Beads are used to treat water laden with estrone.•Maximum adsorption capacity for prepared beads is 6.491 mg/g.
Groundwater in Iraq is considered to be an alternative water resource, especially for areas far away from surface water. Groundwater is affected by many factors including climate change, industrial ...activities, urbanization, and industrialization. In this study, the effect of artificial recharge on the quantity of groundwater in the Dibdibba unconfined aquifer in Iraq was simulated using a groundwater modeling system (GMS). The main raw water source used in the artificial recharge process was the reclaimed water output (tertiary treatment) from the main wastewater treatment plant (WWTP) in Kerbala, with 20 injection wells. After calibration and validation of the three-dimensional numerical model used in this study and taking wastewater recharge rates into account, two different scenarios were applied to obtain the expected behavior of the aquifer when the groundwater levels were augmented with 5% and 10% of the daily outflow production of the WWTP in Kerbala. The model matched the observed head elevations with R2 = 0.951 for steady state and R2= 0.894 for transient simulations. The results indicate that the injection of treated water through 20 wells raised the water table in more than 91 and 136 km2 for 5000 and 10,000 m3/day pumping rates, respectively. Moreover, increasing the volume of water added to the aquifer could lead to establishing new agricultural areas, spanning more than 62 km2, extending about 20 km along the river.
A Genetic Algorithm technique, linked with a numerical solver model (Finite Elements) (GA-FEM), has been evolved to compute the optimal hydraulic design for a safe hydraulic structure to handle ...seepage concerns. The minimum cost of construction was considered the objective function during the formulation of the optimization process. While the major constraints were represented by the uplift pressure beneath the base floor and the exit gradient of seepage flow. The GA-FEM approach proposed in this study addresses the criteria of optimal hydraulic design in two main steps. First, the seepage problem was analyzed using a verified numerical model coded in finite-element programming. Then the Genetic Algorithm technique is used to address the optimal solution model and obtain the optimum (minimum construction costs) location and depth for the cut-offs under hydraulic structures. As a simulation/optimization (S–O) model, MATLAB platform code was utilized to construct a connection between the FEM and the optimization technique. The results refer to the developed GA-FEM model that can yield efficient, economical, and safe hydraulic designs for the cut-offs. The assessment of the GA-FEM proposed model indicated a good agreement between the simulation and expected results for seepage characteristics under the hydraulic structure.
Abstract
The main aim of the current study is to develop a new model for the minimum cost of optimum design for a sewer network with pumping stations. The difficulty and relatively large number of ...nonlinear and discrete constraints in a sewer network with pump station design problems make their handling of extreme importance. For this purpose, an adaptive genetic algorithm (GA) model is proposed for the effective and efficient optimal design with a fixed layout so that each chromosome, consists of diameters, slopes of the pipes and pump indicators. In the present model, the pump locations are decided preliminary, then for each GA chromosome, the network characteristics including the diameters of pipes and slope for those pipes are determined. MATLAB code was used to perform the optimization model. Then a sewer network from previous literature was used to be designed as a benchmark example for the proposed method. It’s concluded that the proposed model has reached the optimal solution at the lowest cost and the fewest number of generations compared with previous methods in the literature.
Abstract
This paper presents finite element analysis of a zoned earth dam considering hydrodynamic force during the earthquake. Geostudio software using the sub-program SEEP/W and QUAKE/W was used. ...The earthquake that is used in this analysis are Iraqi earthquake that happened in Ali Al-Garbi within Missan governorate and El-Centro earthquake. Haditha dam section was used for the hypothetical dam. The maximum height of the dam is 57 m. The shell was constructed from the mix of sand-gravel with the average particles diameter range from (0.24 to 16.7 mm). Three different properties were used for core material, each one of these properties was analyzed under three different heads of water in the upstream side. The main parameters that have the influence on the analysis results are; water level in the upstream side of the dam, intensity of the earthquake, properties of the core material, and the value of hydrodynamic force. The hydraulic flux and peak displacement increase with increasing these parameters.
This study addresses the issue of eliminating Congo red dye from aqueous solutions through green pyrolysis of hybrid iron oxides/graphene-coated iron slag. A novel adsorbent was developed, utilizing ...cost-effective date fruit-derived graphite and iron slag byproducts. The resulting macroporous structures resemble two-dimensional graphene sheets on an iron slag substrate. Optimal production conditions were determined as pH 12 and 1 g/50 mL slag dosage for 3 h, achieving a remarkable dye removal efficiency of over 95%. Furthermore, a maximum removal percentage of 97% was attained at pH 3 within 60 min, using 0.2 g of adsorbent per 50 mL of solution with an initial dye concentration of 50 mg/L. Sorption data fit well with both the Freundlich and pseudo-second-order models. Increasing the number of composite sorbents in the column resulted in enhanced sorption capacity and prolonged breakthrough time, effectively represented by the belter model. Based on these findings, we recommend the application of this innovative adsorbent for efficient removal of Congo red dye from wastewater.
Rainwater Catchment System Reliability (RCSR) is the chance that a system will deliver the required water for an interval of time. Rainwater Harvesting (RWH) is gaining popularity as a potential ...alternative water source for household or agricultural use. The reliability of the Al Abila dam in the western desert of Iraq was analyzed using a water budget simulation model and two explanations of reliability, time-based reliability, and volumetric reliability. To evaluate rainwater harvesting system performance, comprehensive software utilizing a method for everyday water balance using data from 20 years of daily rainfall. According to the findings, volumetric reliability, and for the three climate scenarios (wet, average, and dry year), increased as the storage volume increased until a threshold accrued on the storage capacity of 11.7 × 105 m3. While time-based reliability shows an increase up to a storage volume of 10.2 × 105 m3. Volumetric reliability of roughly 34–75% may be achieved, while only 14–28% time-based reliability may be achieved. Water saving efficiency decreases with increasing demand fraction, while the runoff coefficient has no significant influence on water effectiveness. While growing storage fraction value increases the effectiveness of water conservation and the value of the runoff coefficient influences the water saving efficiency. For both cases, water saving efficiency for the dam does not reach 50%. Using daily rainfall data, the technique given in this paper might be applied to predict water savings and the RWH systems’ reliability in different arid and semi-arid areas.
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