Yiene Molla Desalegn, Endrias Adane Bekele, Getamesay Haile Dagnaw
et al.
Abstract A highly resourceful, environmentally benign, and recyclable magnetic montmorillonite composite (MMT/CF) was obtained through a simple one-step hydrothermal method and exhibited excellent Pb (II) removal. The as-synthesized adsorbent was then characterized by XRD, SEM–EDX, FTIR, BET, and TGA-DTA. The operating parameters including adsorbent dosage, initial Pb (II) concentration, solution pH, and time were studied. Also, a comparative approach was formed between response surface methodology (RSM) and artificial neural network (ANN) to optimize and model the removal efficiency of Pb (II) by MMT/CF. The results indicated that the ANN model was more precise and quite trusted optimization tool than RSM in consideration of its higher correlation coefficient (R 2 = 0.998) and lower prediction errors (RMSE = 0.851 and ADD = 0.505). Langmuir isotherm provided the best fit to the experimental data, and the maximum adsorption capacity was 101.01 mg/g. Additionally, the kinetic studies showed that the pseudo-second-order model fitted well with the experimental data. The magnetic MMT/CF composite possesses high adsorption capacity and is suitable for reuse. Therefore, this study shows that MMT/CF composite can be a potential adsorbent in Pb (II) uptake from aqueous media.
Abstract This study examines the effectiveness of various quantile regression (QR) and machine learning (ML) methodologies developed for analyzing the relationship between meteorological parameters and daily reference evapotranspiration (ETref) across diverse climates in Iran spanning from 1987 to 2022. The analyzed models include D-vine copula-based quantile regression (DVQR), multivariate linear quantile regression (MLQR), Bayesian model averaging quantile regression (BMAQR), as well as machine learning algorithms such as extreme learning machine (ELM), random forest (RF), M5 model Tree (M5Tree), least squares support vector regression algorithm (LSSVR), and extreme gradient boosting (XGBoost). Additionally, empirical equations (EEs) such as Baier and Robertson (BARO), Jensen and Haise (JEHA), and Penman (PENM) models were considered. While the EEs demonstrated acceptable performance, the QR and ML models exhibited superior accuracy. Among these, the MLQR model displayed the highest accuracy compared to DVQR and BMAQR models. Moreover, LSSVR, XGBoost, and M5Tree models outperformed ELM and RF models. Notably, LSSVR, XGBoost, and MLQR models exhibited comparable performance (R2 and NSE > 0.92, MBE and RMSE < 0.5, and SI > 0.05) to M5Tree and BMAQR models across all climates. Importantly, these models significantly outperformed EEs, DVQR, ELM, and RF models in all climates. In conclusion, high-dimensional QR and ML models are recommended as promising alternatives for accurately estimating daily ETref in diverse global climate conditions.
The population growth and consequently lack of fresh water resources, are the main concerns of developed communities. Providing water from air humidity is an efficient, clean, and sustainable solution that can supply sweet and fresh water. In this study, different metal surfaces including copper, steel, and aluminum plates have been prepared as a hydrophobic or hydrophilic surfaces through laser, to investigate the amount of collected water at 294.15 K under fully humid environment (100% humidity), at different encounter angles with plates (45, 70, and 90 °). Moreover, the metal plates along with small or large meshes have been also tested. In addition, polytetrafluoroethylene plates have been prepared via laser in order to water harvesting from humid air. It has been shown that all surfaces treated with laser have better efficiency for water harvesting in comparison with the plates without laser. Likewise, the angle of 45° has had the highest amount of collected water on all surfaces. Eventually, it has been observed that steel plate modified with laser 1 has had higher efficiency for producing drinking water.
I Gusti Lanang Made Parwita, I G B Sila Dharma, Mawiti Infantri Yekti
et al.
The need for clean water is generally divided into two groups, namely domestic water needs and non-domestic water needs. Non-domestic water needs are water needs other than for household purposes such as for education, industry, tourism, social and others. In general, the determination of non-domestic water demand is estimated to be around 20-25% of the total domestic water demand. Badung Regency has characteristics as the main tourist area in Bali as evidenced by the existence of 33 tourist destinations, both cultural tourism, natural tourism, artificial tourism and youth tourism. With these characteristics, this study emphasizes the analysis of non-domestic water needs in the tourism sector. The research was conducted by analyzing various factors related to the need for clean water in the tourism sector such as hotel accommodation, tourism support facilities and the number of tourism objects available. The results of this analysis are compared with domestic water needs according to the existing population. The analysis shows that non-domestic water demand for tourism accommodation (hotels, villas and condominium hotels) is 186.76 liters / second, for tourism objects is 7.64 liters / second, restaurants and bars is 24.21 liters / second.
Abstract Geostatistical techniques have been applied to successfully assess the groundwater quality in the Afigya Kwabre District of Ghana. Forty boreholes were sampled for physicochemical and bacteriological characteristics of the groundwater. Principal component analysis revealed that seven components contain 81.01% of the variation of the original variables. Factor 1 accounted for 31.34% of the total variance, factor 2 accounted for 10.97%, third and fourth factors explained 8.41% and 8.19%, the fifth factor showed 8.13% while the sixth and seventh components showed 7.76% and 6.21% variances, respectively. R-mode cluster analysis showed five clusters. Cluster 1 was made of Na+, Cl−, TH, SiO2, HCO3 − and TDS. Cluster 2 and cluster 3 contained dissolved oxygen (DO), pH, K+ and F−, Br, respectively. Cluster 4 was made of PO4 3− and NO3 −and Cluster 5 had Ca2+, Mg2+, Total. coli, Fecal. coli, SO4 2−, and salinity. Correlation analysis revealed a strong positive correlation between EC and TDS, Mg2+, Ca2+, Mn, Na+, TH, HCO3 −; pH and Ca2+, HCO3 −; Mg2+ and Ca2+, Na+, TH, HCO3 −, Fe; Ca2+ and Na+, TH, HCO3 −; Cu and PO4 3−; Mn and Na+; F− and SO4 2− as well as NO3 − and PO4 3−. The study revealed the impact of both natural processes such as rock mineral weathering, ion exchange, and anthropogenic activities such as application of agrochemicals on farmlands and improper waste disposal on the geochemistry of the groundwater. Generally, the groundwater in the District has a low pH. However, it is generally suitable for domestic use with exception of a few samples with high Fe, F-, Pb concentrations and Escherichia coliform and fecal coliform contaminations. The study has shown that the geostatistical technique is useful in determining the state of water contamination, the extent of contamination, and possible source of contaminants, as well as presenting a guideline for effective groundwater resource management.
Abstract Water shortages have become a major constraint on China's industrial development. Iron and steel industrial parks have a huge demand for water resources and complex production technologies. Therefore, it is very important to study the distribution, transfer and loss of water resources in industrial parks in order to improve the ability to refine water resources management. The purpose of this study was to reveal the water flow in industrial parks by using the principle of water balance and to provide a method for quantification and characteristic recognition of water resources in industrial production processes. In this research, an iron and steel industrial park in North China was chosen as the case study. In order to calculate the water balance of the whole steel production processes, the industrial park was divided into four levels and 110 water units according to the pipe network system and production processes. Based on the results of multi-level and multi-node water balance, this paper analyzed the water intake structure and water consumption structure of industrial parks, and provided the methods to optimize the allocation of water resources and reduce the consumption of fresh water in industrial production processes. The results of the study showed that the energy department accounted for 60.8% of the total water withdrawal of the industrial park. There were 6,249 m3/day of fresh water in the industrial park, which could be replaced by reclaimed water from urban sewage. Evaporation and pipe network leakage were the main water consumption factors in the steel park, which contributed 91.3% of the water consumption. Under the guidance of the research results, the evaporation water consumption of the industrial park was reduced by 8,412 m3/day, and pipe leakage was reduced by 600 m3/day. This article demonstrates the application of the water balance principle in complex water use systems, which is helpful for water resources management based on water use processes.
An increase in the hydraulic capacity of flow conveyance over a weir per a given stage of a stream upstream of the weir is feasible by extending the effective length of the crest of the weir per unit width of flow section. In this work, in order to study the hydraulics of the flow and compare the values of the passing discharge, a 3-D simulation of the flow field on arced labyrinth weirs (single-cycle and double-cycle) was carried out in Flow3D software at the hydraulic loading rate of 0.05 to 0.74 by statistical analysis and the comparison of results obtained from numerical modeling of experimental data. Weirs utilized in this study were three single-cycle weirs (10, 12, and 15 cm in height) and three double-cycle weirs (5, 6, and 7.5 cm in height) examined in a rectangular flume having 8.4, 0.3, and 0.45 m length, width, and height, respectively. The results showed that the data of the numerical model were well conformed to the data of the experimental model. According to the results, a 50% increase in the weir's height will raise the discharge coefficient by 25.5%. Furthermore, the discharge coefficient in a single-cycle arced labyrinth weir at hydraulic loading rates less than 0.4 was higher than the discharge coefficient in a double-cycle arced labyrinth weir. Moreover, the corresponding values were nearly equal at higher hydraulic loading rates.
Environmental sciences, Water supply for domestic and industrial purposes
Thivya Chandrasekar, Chidambaram Sabarathinam, Prasanna Mohan Viswanathan
et al.
Abstract 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.
Proper modeling of groundwater quality is an important tool for planning and decision making in water resources management. The present study was conducted to simulate the groundwater quality parameters of Behbahan Plain including SAR, EC, and TDS using ANN and ANN + PSO models and finally to compare their results with the measured data. Input information to the models gathered were for TDS quality parameter including electrical conductivity, absorption ratio of sodium, sulfate, calcium, magnesium and sodium, for SAR quality parameter including total dissolved salts, sodium, bicarbonate, and for EC quality parameter including sulfate, calcium, magnesium and ratio Sodium uptake from 2010 to 2017. The results indicated that the highest prediction accuracy of quality parameters of EC and TDS is related to the ANN + PSO model with the tangent sigmoid activation function and for the SAR parameter is related to the ANN + PSO model with the logarithm sigmoid activation function so that the MAE and RMSE statistics had the minimum and R2 had the maximum value for the model. In the test phase the values calculated were for EC parameter RMSE=14.61, MAE=9.27, NRMSE=0.41, EF=0.942, and R2=0.96 and for TDSparameter RMSE=22.21, MAE=18.32, NRMSE=0.398, EF=0.925, and R2=0.836 and for SARparameter RMSE=9.45, MAE=7.2, NRMSE=0.301, EF=9.27, and R2=0.974. In addition, the results of the mean comparison between measured and simulated data showed that the predicted values with models were not significantly different with the measured date.
Environmental sciences, Water supply for domestic and industrial purposes
Abstract The design of water resource structures needs long-term runoff data which is always a problem in developing countries due to the involvement of huge cost of operation and maintenance of gauge discharge sites. Hydrological modelling provides a solution to this problem by developing relationship between different hydrological processes. In the past, several models have been propagated to model runoff using simple empirical relationships between rainfall and runoff to complex physical model using spatially distributed information and time series data of climatic variables. In the present study, an attempt has been made to compare two conceptual models including TANK and Australian water balance model (AWBM) and a physically distributed but lumped on HRUs scale SWAT model for Tandula basin of Chhattisgarh (India). The daily data of reservoirs levels, evaporation, seepage and releases were used in a water balance model to compute runoff from the catchment for the period of 24 years from 1991 to 2014. The rainfall runoff library (RRL) tool was used to set up TANK model and AWBM using auto and genetic algorithm, respectively, and SWAT model with SWATCUP application using sequential uncertainty fitting as optimization techniques. Several tests for goodness of fit have been applied to compare the performance of conceptual and semi-distributed physical models. The analysis suggested that TANK model of RRL performed most appropriately among all the models applied in the analysis; however, SWAT model having spatial and climatic data can be used for impact assessment of change due to climate and land use in the basin.
Hamzeh Ghasem Ahangari, Hossein Pourmoghadas, Mohammad Fahiminia
The effluent from the active sludge treatment plant of Qom Shokoohiyeh industrial flows into surface water and reuse of water in industrial process is necessary. The aim of this study was to investigate the efficiency of aluminum sulfate, chlorofluorocarbons and poly aluminum chloride in removing turbidity and other parameters in industrial wastewater before entering RO in Shokoohiyeh Qom industrial refinery. This study was applied in a laboratory scale using a jar-test and experiments based on varying concentrations of coagulants (200, 400, 700, 800, 1000, 1200 mg/L) and pH=2.4.6.7.8.10 has been done. Steady mixing, slow mixing and stagnation have been performed and factors such as turbidity, pH, COD, BOD5, EC, SVI and TSS have been investigated. Coagulants are effective in removing turbidity. The highest removal rate was for polyvinyl chloride (95%) and the least amount of turbidity removal was in chlorofacry (50%). The highest and lowest levels of pH were detected at pH=2 (72%) and pH=8 (10%), respectively. The lowest BOD5 removal efficiency in poly aluminum chloride was 88% at pH=4 and the highest removal rate of BOD5 was found in chloroformate coagulant with pH=4 (96%). The highest COD reduction was observed in poly aluminum chloride at pH=9 (89%) and the lowest COD reduction was observed at a concentration of 800 mg/L alum with 34%. The highest reduction in electric conductivity in poly aluminum chloride with 87% and the lowest amount of electrical conductivity reduction occurred at a concentration of 500 mg per liter of alum with 12%. The highest total removal of suspended solids in chlorofacrylic coagulant was 88% and the lowest amount was removed in chloroform with up to 18%. The maximum amount of sludge deposited at pH=9 (240 mg/L) in aluminum chloride and the lowest amount of sludge deposited at pH=2 (5 mg/L). The use of coagulant materials can increase the purification efficiency, eliminate opacity and return water to the cycle. PAC and Alum coagulant have high efficiency in removing turbidity and other wastewater treatment parameters that can be used to treat wastewater for RO systems.
Technology, Water supply for domestic and industrial purposes
Abstract Wastewater can offer a favorable solution for wastewater treatment. This work reviews series of filters with different particle sizes, namely pozzolan and sawdust, as an alternative for wastewater treatment. A permeability coefficient was determined for each filter. The biofilm was prepared by passing a stream of wastewater containing bacteria through different filters separately. The purification of wastewater was performed on the biofilm with different particles sizes. The results show an inverse relationship between the permeability coefficient and the contact time that affects the efficiency of the filtration. Filtration efficiency yield is around 85–94% for chemical oxygen demand (COD) and around 92–97% for biological oxygen demand (BOD). High efficiency in removing some minerals is also observed by bacteria. The biofilm prepared from wastewater seems to be an efficient agent to filter wastewaters in particular rural areas. The formation of biofilms has significantly reduced bacterial activity and heavy metal content.
Wastewater/runoff reuse is one of the strategies for sustainable water resource management which, based on the consumption type, requires supplementary treatment and standardization due to a wide range of environmental contaminations. Wastewater recycling not only reduces the pressure on fresh water resources but also is so frugal in comparison to the huge costs and the environmental and socioeconomic impacts of water transfer projects, especially between the basins. Nowadays, the application of bio-methods such as constructed wetlands has increased significantly due to the high cost of conventional wastewater treatment approaches. Constructed wetland systems have different design methods depending on the desired outlook (wastewater or runoff treatment). With regards to the flow patern, the system classifies into free water surface flow, and horizontal and vertical subsurface flow. Design configurations of the constructed wetlands depend on the kinematic description of biological reaction as well as the designer’s knowledge of the flow pattern. In this paper, the related literature is reviewed and the required supplementary treatment of secondary effluent of the treatment plant is presented. Then the performance of different types of constructed wetlands in removal of pollutants is investigated. Finally the principles of constructed wetlands design with the aim of harvesting and treating runoff and wastewater have been thoroughly described. The design criteria are presented based on the observed obstacles for such evolution in the field of water recycling. The feasibility of constructed wetlands is then investigated, especially in arid and semi-arid regions. By presenting the justified plan for the system application, the required measures for site selection of such constructed wetland systems are expressed.
Abstract The peel of the edible fruit, Artocarpus nobilis, a plant endemic to Sri Lanka, shows remarkable adsorption capabilities toward Ni(II), a heavy metal ion. Removal efficiency of 50% obtained with air-dried particles (0.710 mm < d < 1.0 mm) of the above waste material under both static and dynamic conditions. It is enhanced to 71% after optimization of shaking time, settling time and processed temperature within a solution pH range of 4.0–7.0. Application of data on linearized Langmuir isotherm model shows a higher regression coefficient of 0.994, as compared to that of the Freundlich model, leading to the maximum adsorption capacity of 12,048 mg kg−1. The amount of biosorption of Ni(II) at equilibrium determined from the pseudo-first-order model is 2259 mg kg−1 which is in good agreement with the experimental value of 2348 mg kg−1. Removal efficiency further increases under dynamic conditions up to 93% by optimizing the packing bed height and flow rate. Application of dynamic adsorption models, namely Thomas, Adams–Bohart and Yoon–Nelson, shows attractive results with high regression coefficients. It is conclusively demonstrated that the peel of Artocarpus nobilis fruit can be used as an effective biosorbent for the removal of Ni(II) from wastewater.
Somayeh Rahdar, Mahmoud Taghavi, Razieh Khaksefidi
et al.
Abstract Recently, arsenic-contaminated water has become a big concern. Therefore, the present study aimed to absorb arsenic from the aqueous solution using modified saxaul tree ash. Arsenic adsorption process was performed in vitro by investigating the effect of various parameters such as pH, contact time, arsenic concentrations, temperature and adsorbent dosage on the adsorption efficiency. Isotherms, kinetics and thermodynamic studies were also conducted to better understand the process of adsorption. Maximum level of arsenic adsorption was obtained at a pH of 7, adsorbent dosage of 1.5 g/L, contact time of 60 min, initial arsenic concentration of 250 µg/l and temperature of 323 K. The amount of adsorbed arsenic was increased with increasing initial concentration of arsenic and temperature. Freundlich adsorption isotherm clearly described the arsenic adsorption by modified saxaul ash. Based on the results obtained, it could be concluded that the modified saxaul ash can efficiently remove arsenic from its aqueous solutions.
Bioretention can reduce surface runoff, slow down peak flow, and delay peak time by increasing the infiltration capacity of the underlying surface. The media structure directly affects the performance of bioretention systems. Four pilot tanks with different media configuration were built, and hydraulics and water volume reduction were studied though intermittent, simulated storm events. The results showed that water volume and peak flow reduction rate were the most stable and efficient for #1 (fly ash mixing sand, 1:1 by volume) than other systems, which were 58.6–67.9% and 72.0–86.4%, respectively. Partial least squares regression (PLS) was used to build a model for the relation between water volume reduction rate and its influencing factors (R2 = 0.76), and the factors that influence bioretention water volume reduction were ranked from strongest to weakest as follows: infiltration rate (IR) > submerged area height (SAH) > inflow volume (IV) > antecedent dry time (ADT). In addition, volume reduction rate exhibited a positive correlation with ADT and SAH, and a negative correlation with IR and IV. Three water transfer simulations with different infiltration rates were conducted using HYDRUS-1D under designed inflow conditions, and the minimum relative error is obtained for #1.
Sona Chavoshi, Gorban Asgari, Abdolmotaleb Seid-mohammadi
2, 4-Dichlorophenol is one of the most common and abundant pollutants widely found in various industrial effluent. The obvious effect of this organic compound on health and environment depends on enhancing the degradation efficiency of this aqueous pollutant before wastewater being discharged into the receiving water. Therefore, in this study, removal of 2, 4-dichlorophenol from aqueous solution was investigated through using UV-LED/TiO2 process. In this experimental study, removal of 2, 4-DCP in the presence of TiO2 by using UV-LED in a bench scale reactor was examined. The effects of operational parameters such as pH (3-11), initial concentration of 2, 4-DCP (50-200mg/L), TiO2 concentration (0.003-0.025mol/L) and ionic strength were evaluated. The results indicated that removal of 2, 4-DCP was influenced by different operational parameters. The highest 2, 4-DCP removal rate were obtained at pH=3 by adding 0.012 mol/L of TiO2 to solution with an initial concentration of 50mg/L of 2, 4-DCP which more than 95.82% of 2, 4-DCP was removed. While UV-LED and TiO2 were used separately, the 2, 4-DCP removal efficiency was 32.11% and 36.56%, respectively. Also, the results indicated that maximum COD removal rate was 71.5% in optimum condition and also indicated lack of impact on ionic strength changes for removal of organic material. The results indicated that combined TiO2/UV-LED process in optimal conditions can be used as a new technology for treatment of various industrial wastewater containing 2, 4-DCP.
Technology, Water supply for domestic and industrial purposes