Water scarcity is a critical challenge for the global economy in the 21st century, particularly in arid and semi-arid countries such as Iran. Virtual water imports – the water embedded in imported goods – have emerged as an important mechanism to alleviate domestic water shortages. However, the macroeconomic implications of VWI remain underexplored, especially in resource-constrained economies. This study addresses this gap by analyzing the impact of VWI on key macroeconomic indicators in Iran over the period 2003–2022, including trade balance, GDP growth, government revenue, government expenditure, and foreign exchange reserves. To capture the dynamic interrelationships among these variables, a VAR model is employed.The empirical strategy integrates both financial cost and opportunity cost perspectives to provide a comprehensive assessment of how VWI shocks propagate through the macroeconomic system. Standard time-series procedures, including unit root tests and information-criterion – based lag selection, are applied, followed by impulse response functions and forecast error variance decomposition to analyze the short – and long-run effects of VWI shocks. The estimation results indicate that VWI exerts a significant negative impact on Iran’s trade balance, with a first-lag coefficient of −0.18, and reduces foreign exchange reserves by 0.09% in the first period and an additional 0.04% in the second period. GDP growth is adversely affected, with a reduction of −0.11 in the first lag, reflecting resource misallocation and diminished economic efficiency. In contrast, VWI contributes positively to government revenue in the short run, with a first-lag coefficient of +0.13, highlighting short-term fiscal benefits. The variance decomposition results further show that VWI shocks account for approximately 47% of the long-run fluctuations in the trade balance and 36% of the variability in economic growth. The findings highlight the dual nature of VWI: while they help mitigate immediate water scarcity, they simultaneously impose significant long-term economic and external-sector trade-offs. For Iran and similar water-scarce economies, these results underscore the need to reduce structural dependence on VWI through investment in water-efficient technologies, enhancement of agricultural productivity, and broader economic diversification. Aligning such strategies with the Sustainable Development Goals can strengthen macroeconomic resilience, preserve foreign exchange reserves, and support sustainable long-term growth.
Cultural perspectives on water are deeply ingrained in the fabric of the world's cultures, shaping how societies manage and value this essential resource. In some cultures, water is considered sacred and is used sparingly and respectfully, emphasizing its intrinsic value and the need to protect this precious resource. In contrast, other cultures may view water as an abundant resource, leading to overuse and waste, and unsustainable water management practices. Cultural views also influence the acceptance and success of water management policies and technologies. For example, in cultures where water is considered a common resource, policies that emphasize individual rights to water may not be accepted. Culture also plays a unique role in socio-hydrology research. This article examines water culture using a configurational approach. What is clear is that many cultural traditions around the world honor water as a sacred and life-giving element, have a symbiotic relationship with it, and consider it a social good that belongs to everyone. New practices have often ignored these cultural traditions and expanded the paradigm of technology-based water management with dominance over nature. Modern technologies may temporarily enhance humans' sense of control over nature, but the idea of controlling water is a flawed mindset, and instead of controlling it, society must continue to live in harmony with nature and achieve sustainable water management by optimally combining old and new methods. This article presents implications for culture-based water resources management and governance.
Among the various methods developed to reduce excess sludge in activated sludge processes, the Oxic-Settling-Anoxic process has attracted considerable attention due to its low cost, operational simplicity, and compatibility with existing wastewater treatment plants. When OSA process is integrated with a Sequencing Batch Reactor system, a portion of the activated sludge from the SBR is passed through an anaerobic side-stream reactor and then returned to the aerobic reactor. This approach promotes endogenous decay and uncouples catabolism from anabolism, resulting in less excess sludge production. In this study, the performance of the OSA process was enhanced by integrating ultrasonication and hydrogen peroxide (H₂O₂) oxidation in a laboratory-scale SBR. A pilot system was operated under different configurations, including a conventional SBR (as control system), OSA, OSA combined with ultrasonication, OSA integrated with H₂O₂ oxidation, and the combined OSA, ultrasonication and H₂O₂ system. The system performance was evaluated using the biomass yield coefficient (Y), sludge reduction efficiency, and COD removal efficiency. The Y for SBR was determined as 0.70 mg MLVSS/mg COD removed. Incorporating the OSA process reduced Y to 0.20 mg MLVSS/mg COD removed, corresponding to approximately 71% sludge reduction. Adding ultrasonication and H₂O₂ oxidation to the system decreased Y to 0.16 and 0.15 mg MLVSS/mg COD removed, representing sludge reductions of approximately 77% and 79%, respectively. The combined OSA, ultrasonication and H₂O₂ system achieved the lowest Y of 0.11 mg MLVSS/mg COD removed, showing an overall sludge reduction of 85%, while COD removal efficiency remains above 85%. The results demonstrate that combining biological (OSA), mechanical (ultrasonication), and chemical (H₂O₂ oxidation) treatments provides a synergistic approach for minimizing excess sludge production while preserving satisfactory treatment performance. This integrated strategy highly reduces the sludge management costs and environmental impacts in activated sludge wastewater treatment systems which is of high importance.
This study aims to support eco-friendly wastewater treatment by converting lignocellulosic waste into valuable biosorbents, thereby contributing to sustainable waste management technologies. Wheat straw and its ash were examined as low-cost adsorbents for the removal of industrial ionic dyes, including cationic methylene blue and anionic methyl orange. To enhance adsorption performance, several surface modification approaches, including alkaline, acidic, and ultrasound-assisted treatments, were evaluated. The structural and surface characteristics of the modified materials were analyzed using Brunauer–Emmett–Teller and Fourier transform infrared spectroscopy techniques. Among all prepared adsorbents, the sodium hydroxide–ultrasound-modified ash (WSA-U-NaOH) exhibited the highest adsorption efficiency under initial testing conditions (25 mg/L dye), achieving capacities of 12.38 mg/g for MB and 4.47 mg/g for MO, evidencing a synergistic enhancement attributable to the combined effects of alkaline activation and ultrasonic cavitation. Optimization using the Taguchi model revealed that the maximum adsorption capacity for MB (53.29 mg/g) occurred at pH=12 with 0.05 g of adsorbent and an initial MB concentration of 75 mg/L after 45 minutes. For MO, optimal conditions (pH=2, 0.05 g adsorbent, and 75 mg/L MO) produced a capacity of 22.36 mg/g after 60 minutes. The adsorbent exhibited a markedly higher affinity toward the cationic dye, consistent with electrostatic interactions governed by surface charge characteristics. Kinetic analyses showed that adsorption followed the pseudo-second-order model, suggesting chemisorption as the dominant rate-controlling step. Equilibrium data were best fitted by the Freundlich isotherm, indicating heterogeneous multilayer adsorption. Thermodynamic parameters confirmed that the biosorption of both dyes was spontaneous and endothermic.
Climate change, the quantitative and qualitative decline of water resources, and the increasing demand for water consumption are among the most significant challenges for sustainable drinking water management, particularly in arid and semi-arid regions. These conditions highlight the urgent need to reconsider conventional approaches to drinking water supply and distribution and to move toward more sustainable solutions. The metropolitan city of Tabriz, owing to its semi-arid climate, rapid population growth, and considerable dependence on inter-basin water transfer, has faced serious challenges in ensuring a sustainable drinking water supply in recent years. Accordingly, the present study aims to evaluate and compare alternative drinking water distribution scenarios based on the separation of potable water from domestic (non-potable) water. In this study, five scenarios-dual distribution network, local water withdrawal stations, household water treatment systems, bottled water in single-use containers, and bottled water in reusable containers-were evaluated using a group multi-criteria decision-making approach based on the analytic network process and fuzzy decision making within the group fuzzy decision-making software. The final ranking of scenarios was performed using the simple additive weighting method. The evaluation was conducted based on five main criteria-technical, economic, social, environmental, and political-and 18 key sub criteria, including important indicators such as carbon footprint and public acceptance. The required data were collected through expert judgments and the analysis of 659 public questionnaires. The results indicated that the technical (0.1157), economic (0.1089), and social (0.1073) criteria were considered the most important from the decision-makers’ perspective, while the political criterion received the lowest weight. Furthermore, the dual distribution network scenario, with a score of 0.8014, was identified as the most sustainable option and demonstrated superior performance compared with other scenarios across most evaluation criteria. The findings of this study indicate that decision making in sustainable drinking water management requires a comprehensive and multi-dimensional approach combined with stakeholder participation. This study provides a framework based on group multi-criteria decision-making for the simultaneous evaluation of alternative drinking water distribution scenarios, considering a comprehensive set of evaluation criteria in a semi-arid metropolitan area. The proposed framework can serve as a basis for planning and decision making in other regions facing water stress and similar climatic conditions.
Oil effluents contain persistent volatile organic compounds, hydrocarbons, chlorinated substances, and heavy metals. The emission of organic compounds is of interest to many research and environmental organizations due to their destructive environmental effects and the risks they pose to the workers of these complexes. In this study, the fabrication of modified composite membranes for the removal of heavy metals from industrial effluents was studied experimentally. Membranes were fabricated by interfacial polymerization method and FTIR, XRD, EDX, SEM and contact angle analyses were performed. By increasing the concentration of Fe3O4/APTES nanoparticles from 0 to 0.3 wt%, the contact angle of the nanocomposite membranes decreased from 3.74° to 4.54°. After 60 minutes, the water flux through the M0 membrane is approximately 25.91 L/m2.hr and the water flux through the M1, M2 and M3 membranes is 36.91, 98.103 and 36.125 L/m2.hr, respectively. The performance of different membranes for the removal of heavy metals-strontium (Sr), copper (Cu), lead (Pb) and cobalt (Co)-present in water under operating conditions of 10 bar pressure, 2 L/min flow rate, 60 minutes time and ambient temperature showed that the modified membrane with 0.1 wt% Fe3O4/APTES concentration (M2) has the best performance compared to other membranes. The highest percentage of heavy metal removal was obtained with the M2 membrane, achieving 36.57% for Sr, 56.86% for Cu, 64.72% Pb and 65.89% for heavy metals. The M2 membrane can recover about 21.8% of the water flux compared to 8.2% of the M0 membrane, indicating the higher performance of the M2 membrane in improving the water flux through the membrane.
Nowadays, water management through the use of non-conventional water resources has gained attention as a means of reducing pressure on local natural water resources. One of the most widely used non-conventional water resources is treated wastewater, or effluent, which has been the subject of numerous studies, and whose benefits are recognized worldwide. In the process of effluent utilization, the location of the wastewater treatment plant is of great importance. To determine the most suitable sites for WWTP construction, large-scale zoning of suitable and restricted areas based on various effective criteria is essential. In this study, after examining the criteria required for zoning, suitable and restricted areas for WWTP construction in Isfahan were identified by defining the most important siting criteria in GIS software. For this purpose, nine constraint criteria were used, including slope, rivers, the 25-year floodplain, faults, power transmission lines, transportation networks, protected areas, urban and rural residential areas, and population centers. The results showed that 612.90 km² (39.13%) of the total study area was suitable for WWTP construction, whereas 953.55 km² (60.89%) was restricted. The results also indicated the significant influence of population centers and urban and rural residential areas on the spatial suitability pattern. The highest percentages of restricted land were associated with population density (45.67%), urban areas (34.65%), and population centers (29.09%). In contrast, the lowest shares of restricted land were associated with minor roads (0.25%), protected areas (0.65%), and power transmission lines (0.91%). The final spatial suitability map showed that one of the existing WWTPs is located within a restricted area.
Cypermethrin and permethrin are two widely used pyrethroid insecticides in agriculture and household pest management, which can enter surface water sources through urban sewage and agricultural runoff due to their relative stability and high tendency to bind to sediment particles. The aim of the present study was to assess the environmental risk and human health hazard index based on the concentrations of cypermethrin and permethrin toxins in the Gorgan Rood river. Sampling was conducted at five stations, in two seasons, spring and summer 2024, and repeated 3 times a week. After solid phase extraction, the samples were analyzed by high-performance liquid chromatography. The limit of detection was determined based on the signal-to-noise ratio (S/N=3) and using data from the HPLC instrument used in this study. The results showed that permethrin was not present in any of the samples, while cypermethrin increased from the upstream station to the downstream, especially in summer (maximum 0.43 ppm). In addition, the increase in cypermethrin concentration was accompanied by an increase in EC, TDS, water temperature, and a decrease in dissolved oxygen. The environmental risk assessment showed that in the summer season, the PEC/PNEC ratio at Basirabad station approached the warning threshold (0.22), while other stations were at a lower risk level. The health hazard quotient for humans at all stations was less than 1, indicating a direct non-carcinogenic risk through water consumption. Providing empirical evidence, this study highlights the need for integrated water resources management to reduce ecological exposure to pyrethroids and emphasizes the need to develop management strategies based on continuous monitoring and reduction of pollutant loads in the Gorgan Rood river.
The considerable water consumption associated with Iranian-produced evaporative coolers is evident given Iran’s water shortage and diminishing water resources in Iran. Although Iranian-produced evaporative coolers have an older design and are well suited to the atmospheric conditions of Iran, which are mainly hot and semi-arid, their high water consumptions and the lack of water resources, particularly in summer, highlights the need for more scientific research. This should include new ideas and techniques aimed to reduce water consumption in these devices. In this study, a new dynamic air cooling system is introduced, by which atmospheric air can be cooled to -90 oC without the use of conventional refrigeration systems. The dynamic air cooling system represents a novel and innovative method on a global scale.Based on the scientific principles of gas dynamics and thermodynamics, it is able to increase the speed of air passing through this system to supersonic values in several stages, consequently reducing the temperature of the air passing through the system or its sensible energy, significantly. This innovative system is currently being used commercially in industrial cold stores. In the current work, by using the cold air produced by this system, the temperature of the circulating water in evaporative water coolers is significantly reduced, and the amount of water consumption in evaporative water coolers is reduced. It is shown that by using the cold air produced by the dynamic cooling system, the temperature of the circulating water is reduced from the wet bulb temperature of the ambient air to a temperature of 4 oC; in these conditions, the cooling load and the seasonal energy efficiency ratio increase by 97% and 29.2%, respectively, while the water consumption rate and specific water consumption decrease by 35.2 and 67.5%, respectively. Therefore, by using this system in evaporative water coolers produced in Iran, the water and energy consumption rates are both significantly reduced.
The aim of this study is to evaluate the economics and optimize the electrocoagulation process for the treatment of a real wastewater sample from oil refining with an initial COD of 406 mg/L using scrap aluminum as perforated electrodes (anode and cathode) and solar energy received by the solar panel to provide the electricity required for the process. Electrolysis time (0 to 60 min), current density (6.98 to 34.9 A/m2), and electrode spacing (1 to 5 cm) were investigated using the response surface methodology, while central square design was used to determine the optimal experimental conditions. The experimental results indicate the significance of slectrode spacing, in addition to current density, which is directly dependent on the number and size of holes created on the electrode. Economic evaluations indicate the possibility of using scrap aluminum as a replacement for regular aluminum, which led to savings in operating costs. Finally, the optimal conditions for conducting experiments were obtained with an electrolysis time of 48 min, a current density of 92.27 A/m2, and an electrode distance of 2 cm. Under these conditions, the COD and TDS removal percentages were 70 and 15.3%, respectively, which is relatively in line with the predictions of the designed model (68.7 and 15.1 percent, respectively). According to the calculations made in this study, and considering the costs required to provide solar energy with the current energy price in Iran (Tehran), the use of solar energy to provide the energy needed for the electrocoagulation process on a small scale is not recommended. One of the main reasons for the inefficiency of solar energy use on a smaller scale is the low cost of industrial electricity in the country.
Given the intensification of water scarcity and increasing water demand, the reuse of treated industrial wastewater can be considered as a sustainable water resource. The aim of this study was to evaluate the performance of a lab-scale membrane bioreactor for improving the quality of the effluent from the industrial wastewater treatment plant of Shokouhieh Industrial Town for reuse purposes. The study focused on the simultaneous analysis of suspended solids removal, organic load reduction, and the limitation of the process in reducing dissolved salts, in order to evaluate the reuse potential of the effluent from the perspective of final end-use water quality. A plexiglass reactor with an effective volume of 32 L was operated continuously for 35 days, and the influent flow rate was set at 4 L/h (HRT≈8 h). Solids separation was carried out using a flat-sheet ultrafiltration membrane with a molecular weight cut-off of 150 kDa. During the operation period, influent and effluent samples were collected, and COD, TSS and TDS were measured according to standard methods. The results showed that the average COD decreased from 321 to 68 mg/L, corresponding to 79% removal, and the average TSS decreased from 99 to 2 mg/L, corresponding to 98% removal. In addition, TDS decreased from 1134 to 960 mg/L, corresponding to an approximately 15% reduction, which is consistent with the inherent limitation of UF membranes in removing dissolved salts. Therefore, in applications where further reduction of dissolved salts is required, complementary processes such as nanofiltration or reverse osmosis are recommended. Overall, the studied MBR showed a high capability for suspended solids removal and organic load reduction and, considering the quality requirements of the intended end use, can be regarded as a reliable option for some reuse applications. The 35-day monitoring period demonstrated the performance trend of the system under real wastewater conditions, and the results can provide a basis for the design and evaluation of longer-term pilot-scale experiments in future studies.
Contamination of surface and groundwater by chemicals and wastewater poses a serious threat to human health and ecosystems. Synthetic dyes are persistent pollutants with complex structures. Eosin Y, commonly used for tissue staining, is often discharged into wastewater without treatment, posing risks to both human health and the environment. In recent years, the use of photocatalysts has attracted significant attention due to their effective performance and environmental compatibility. Graphitic carbon nitride is a non-metallic photocatalyst known for properties such as high chemical stability, low toxicity, easy availability, and the ability to operate under visible light. However, this material has drawbacks, including rapid electron–hole recombination, a high weight-to-performance ratio, and low visible-light absorption. To enhance its performance, titanium dioxide waste from the Claus process in gas refineries has been employed. In this study, the effects of various factors such as pH, the titanium dioxide to graphitic carbon nitride ratio, photocatalyst dosage, and dye solution temperature on the dye removal efficiency were investigated. For each factor, 30 mg of the synthesized photocatalyst was tested in 100 mL of Eosin Y solution under irradiation from a 200 W visible-light lamp. FESEM images also confirmed the presence of titanium dioxide nanoparticles on the graphitic carbon nitride sheets. Functional groups of the materials were identified using FTIR analysis. DRS analysis showed that the g-C3N4/TiO2 nanocomposite has a reduced bandgap. The presence of C, N, O, and Ti elements in the photocatalyst was confirmed by EDAX analysis. Under optimal conditions and visible light, the dye removal efficiency exceeded 97%. The photocatalyst with a 2:1 ratio of g-C3N4 to TiO2 demonstrated significant stability, removing more than 90% of Eosin Y after 8 consecutive cycles.
Global water scarcity and the increasing demand from industrial sectors have made wastewater recycling an essential strategy for sustainable resource management. Among various industrial effluents, spent caustic wastewater from petrochemical units is considered one of the most challenging and hazardous streams due to its high alkalinity, high sulfide content, unpleasant odor, and toxicity. Inadequate treatment or disposal of this effluent can severely contaminate water bodies and threaten both human health and aquatic ecosystems. Therefore, the development of efficient, economical, and environmentally friendly methods for sulfide removal has become a critical priority. This study investigated the potential of hydrodynamic cavitation as a treatment technology for sulfide removal from spent caustic wastewater. A semi-industrial pilot reactor equipped with an orifice-plate cavitation device was designed and operated using synthetic wastewater simulating real effluent. The influence of key operating parameters - including inlet pressure (3 to 5 bar), initial temperature (20 to 40°C), residence time (0 to 120 minutes), sulfide concentration (5 to 20 mg/L), and the addition of oxidants (1000 mg/L H2O2 and 45 L/min of air) - was systematically investigated using a single-factor approach. The results indicated that at the optimal pressure of 4 bar and a temperature of 30°C, more than 90% of sulfide removal was achieved in less than 60 minutes, with complete removal achieved within 90 minutes. Increasing the retention time led to a higher number of recirculation cycles (over 70 cycles) and improved removal efficiency. At an initial concentration of 5 mg/L, complete sulfide removal occurred in less than 60 minutes, whereas at 20 mg/L, approximately 50% removal was achieved within the first 30 minutes, with complete removal after 90 minutes. The addition of air or H2O2 alone did not yield significant improvement; the high peroxide dose converted part of the OH• radicals into weaker HO2• species, and excessive aeration reduced the intensity of bubble collapse, thus reducing the system’s oxidative capacity compared to pure HC. The data showed good agreement with zero-order (R2 = 0.89–0.99) and pseudo-first-order (R2 = 0.85-0.98) kinetic models. The cavitation yield was calculated as 0.0025 mg/J, and the treatment cost under optimal conditions was estimated at approximately 44060 Rials per cubic meter of wastewater. The results show that the hydrodynamic cavitation, without the need for chemical additives, is an efficient, cost-effective, and sustainable method for removing sulfide from high-salinity spent caustic wastewater.
Methylene blue is the most common dye in the world for dyeing cotton, wool and silk with high consumption and is found in large quantities in textile industry wastewater. This dye is cationic, toxic, carcinogenic and non-biodegradable. Therefore, its removal from wastewater is one of the concerns of researchers. Considering the problems in using homogeneous catalysts, in this study, new nanocatalysts based on thallium oxide immobilized on silica substrate (Tl2O3-SiO2) modified with Schiff base complexes of N2O2 and vanadium were synthesized and their efficiency in removing methylene blue from wastewater was evaluated using these heterogeneous catalysts. FTIR, 1H NMR, EDX, XRD, TEM, and FESEM methods were used to fully identify these complexes and nanocomposites. In the next step, the ability of Schiff base-nanocomposite catalysts to remove methylene blue was investigated by UV-vis spectroscopy at specific time intervals and the effect of various factors was determined. The value of 0.2 mg/L was selected as the optimal amount of adsorbent. According to the results of the experiments, the concentration of 100 ppm of methylene blue was selected as the optimal concentration. pH=10 and time of 60 minutes showed the best performance of the adsorbent. Methylene blue dye was decomposed using photocatalysts Tl2O3@SiO2.VL2 and Tl2O3@SiO2.VL1 with an efficiency of 82 and 95%, respectively. VL1, VL2. They had bromine (σp≈0.23) and nitro (σp≈0.68) groups on the benzene ring. Therefore, due to the larger Hemmett constant in VL1, the adsorption efficiency is higher. The experimental results showed that the Tl2O3@SiO2.VL1 system has an adsorption of 475 mg/g with an efficiency of 95%. The Langmuir separation factor (RL) showed a value of 0.88, which confirms the desirability of the adsorption process. The immobilization of vanadium complexes on the mineral substrate not only increased the stability of the catalyst and its recyclability, but also increased the adsorption efficiency by up to two times compared to conventional adsorbents due to the synergistic effects between the thallium and vanadium metal centers. This degradation follows first-order kinetics. The adsorbent material showed relatively good reproducibility. This nano-adsorbent is proposed as an efficient and sustainable option for the treatment of industrial wastewater.
Conformity assessment of drinking water quality test results, particularly under critical water supply conditions, requires decision rules approaches that protect consumer health and prevent unjustified rejection of acceptable water sources. In this study, conformity assessment and decision rules based on measurement uncertainty were investigated for the acceptance or rejection of Nitrate, Turbidity, and pH test results in drinking water. These measurands were selected due to their importance in water quality and their direct or indirect impacts on human health. The primary objective of this research was to determine the probability of conformity of test results with regulatory requirements and to highlight the role of measurement uncertainty in reducing the risk of incorrect decisions, especially when new water sources are introduced into the distribution network. Nitrate, Turbidity, and pH analyses were conducted in accordance with the latest edition of the Standard Methods for the Examination of Water and Wastewater. Measurement uncertainty was estimated separately for each measurand, and conformity assessment was performed with reference to the permissible limits specified in the Iranian National Drinking Water Standard No. 1053. Based on these inputs, the probability of conformity for each test result was calculated and used as the basis for acceptance or rejection decisions. The results demonstrated that applying a decision rule based on measurement uncertainty can significantly influence conformity assessment outcomes for drinking water quality parameters. The calculated probabilities of conformity were 95% for Nitrate, 90% for Turbidity, and 85% for pH, indicating different levels of decision confidence for the three measurands. These differences suggest that for certain measurands-particularly Nitrate, which has a more direct impact on human health-the risk of incorrect decision rules is higher, and measurement uncertainty must be considered more rigorously when declaring conformity. The findings further indicate that reliance solely on raw measurement results, without incorporating measurement uncertainty, may lead to the incorrect acceptance of unsafe water sources or the unjustified rejection of compliant ones. Overall, this study emphasizes that implementing a measurement uncertainty-based approach in the conformity assessment of drinking water test results enables informed decision rules with defined and acceptable risk levels. Adoption of this approach enhances decision accuracy, reduces risks to consumer health, prevents unnecessary rejection of acceptable water resources, and contributes to more efficient resource utilization and avoidance of unnecessary costs in water supply management systems.
Organic dyes such as Crystal Violet represent persistent and toxic pollutants in industrial wastewaters, underscoring the urgent need for efficient removal methods. This study investigates the performance of two adsorbents-carbon nanotubes and biochar-in removing Crystal Violet dye. FESEM and EDS analyses were employed to identify the morphology and chemical composition of the adsorbents. The average particle size was determined to be 26.32 nm for carbon nanotubes and 72.09 nm for high-purity biochar. Adsorption experiments were conducted under various conditions of adsorbent dosage, contact time, and temperature, and the optimum adsorbent dose and equilibrium time were determined to be 1 g/L and 90 min, respectively. Increasing the adsorbent dosage resulted in a decrease in specific adsorption capacity due to a reduced ratio of dye molecules to available active sites and particle agglomeration. Adsorption isotherm analysis revealed that the Freundlich model for carbon nanotubes and the Temkin model for biochar provided the best fit to the experimental data, and the extracted qmax values confirmed the high adsorption capability of both adsorbents, while pH showed no significant influence on the adsorption process. Kinetic and thermodynamic investigations indicated that adsorption was mainly governed by intraparticle diffusion, was spontaneous and endothermic in nature, and involved an increase in surface randomness, which was further supported by FESEM images and EDS analysis, confirming effective dye attachment on the adsorbent surfaces. The findings of this study demonstrate that both carbon nanotubes and biochar exhibit high potential for the removal of organic dyes, with the intraparticle diffusion mechanism playing a key role in the adsorption process. Moreover, the good agreement of the Freundlich and Temkin models with the experimental data indicates the heterogeneous nature of the adsorbent surfaces.
Heavy metals such as nickel in aqueous environments pose significant risks to both human health and natural ecosystems, owing to their pronounced toxicity, environmental persistence, and tendency to bioaccumulate within food chains. In this study, a novel magnetic graphene oxide nanocomposite functionalized with an allylamine–vinyl imidazole copolymer (Poly-g-MGO) was synthesized and utilized as an efficient adsorbent for removing Ni(II) ions from aqueous solutions. Optimum adsorption conditions were established through batch experiments at pH=7, a contact time of 80 minutes, an adsorbent dosage of 0.25 g L−1, and a temperature of 298 K, with an initial Ni(II) concentration of 20 mg L−1. The removal efficiency of Ni(II) reached 90% under these conditions. The adsorption equilibrium data were best described by the Freundlich isotherm model, indicating a multilayer adsorption process on a heterogeneous surface. The Langmuir model estimated a maximum monolayer adsorption capacity of 133.366 mg g−1. The adsorption capacity diminished as the temperature increased from 298 to 328 K, confirming the exothermic nature of the process. Kinetic studies revealed that the adsorption followed a pseudo-second-order kinetic model, with intra-particle diffusion playing a dominant role in the adsorption mechanism. The adsorbent's practical applicability was further evaluated in real water samples, including tap water, Zayandeh-rood river water, and spent caustic industrial wastewater. The lower removal efficiency in industrial wastewater was attributed to the competitive adsorption of coexisting ions. These findings demonstrate the high capability of Poly-g-MGO for Ni(II) removal and its potential for treating contaminated aqueous samples.
The water scarcity crisis in Tehran Province and the Varamin Plain, coupled with frequent water and power outages, has led to air entrainment in pipelines, increased pressure, and pipe bursts, highlighting the need for intelligent water management in the deployment of emergency response teams. The innovation of this study lies in applying artificial intelligence–based methods for spatial analysis of incidents and identifying optimal locations for the deployment of mobile emergency teams. The main focus is on reducing response time and improving service coverage through the determination of optimal points using the Self-Organizing Map algorithm. This innovative approach contributes to the development of integrated software for incident management and faster decision-making under emergency conditions. The study area covers four counties: Varamin, Pishva, Qarchak, and Pakdasht. Using the Self-Organizing Feature Mapneural network algorithm, 16 optimal points for the deployment of mobile emergency teams were identified to enhance coverage and reduce response time, thereby minimizing losses caused by water and power disruptions. A total of 3,603 incident points recorded in the GIS system with UTM coordinates (Zone 39N) were used for spatial analysis and clustering in MATLAB. The research process included spatial data collection and preprocessing, SOM execution, and output map generation in the GIS environment. Among the 16 optimal locations, 9 are situated in high-incident-density areas (more than 8 incidents per square kilometer), and 6 are located in zones with high customer density (over 1,666 customers per square kilometer). The distribution of other points across lower-density zones ensures adequate coverage of rural and sparsely populated areas. The results indicate that the SOM algorithm successfully identified spatial patterns of incidents and population density, achieving balanced and efficient site selection for mobile emergency teams. The main advantage of SOM lies in its ability to analyze two-dimensional spatial data precisely, preserve topological structure, and adapt to data variability-making it superior to other clustering and metaheuristic methods. The findings confirm that the SOM algorithm is an effective approach for urban crisis management and optimal deployment of emergency resources, with potential for further development using more complex datasets to enhance rapid response systems.
Pressure is one of the most important hydraulic parameters in urban water distribution networks and deviations from the permissible range can lead to increased leakage, reduced equipment lifespan, and energy losses. Although Pressure Reducing Valves are widely used as the most common tools for pressure management, this approach leads to considerable energy dissipation. In recent years, Pumps As Turbines has been used as an alternative or complementary element compared to PRVs, particularly in networks with significant differences in elevation and excess head, has become common. However, most previous studies have either focused primarily on energy generation or have not comprehensively investigated the hydraulic impacts of PATs based on Pressure Driven Analysis. In this study, the performance of PATs and PRVs in terms of pressure management, leakage, and energy recovery is comparatively investigated for the Baharestan WDS in Isfahan Province using PDA and a 24-hour Extended Period Simulation. The network was modeled considering three scenarios including: without valve, with PRV, and with replacement of PRVs by PATs. The results showed that PRV installation reduced the average network pressure from 51.11 to 35.91 m and decreased the average leakage from 64.65 to 44.26 L/s. However, replacing PRVs with PATs resulted in smaller reductions in pressure and leakage (average pressure of 45.03 m and leakage of 59.56 L/s) compared to PRVs, but enabled energy recovery of 73.28 kW during the 24-hour EPS. Overall, the results indicate that PRVs are more effective in pressure control and leakage reduction, whereas PATs, while maintaining hydraulic stability, offer substantial potential for recovering dissipated energy. These results suggest that PATs should not be considered a complete replacement for PRVs, but rather a complementary option to support informed decision-making in pressure and energy management of UWDN.
In this study, polymeric waste was utilized to produce a stable and environmentally compatible catalyst for the removal of high concentrations of cyanide from water. A heterogeneous Fenton-like process was employed, in which activated carbon derived from polymeric waste served as the catalytic support and was impregnated with copper oxide (CuO) nanoparticles. The catalyst was characterized by X-ray diffraction, confirming the presence of crystalline CuO and AC phases. Field-emission scanning electron microscopy combined with energy-dispersive spectroscopy demonstrated a uniform dispersion of CuO nanoparticles (~50 nm) across the porous carbon surface, while Brunauer Emmett Teller analysis demonstrated a high specific surface area (2174 m²/g in AC and 1332 m²/g in CuO/AC) and mesoporous structure (average pore diameter≈2.2 nm). Catalytic performance tests revealed that under optimized conditions (pH≈11, ambient temperature, H2O2-to-cyanide molar ratio of 3, and a catalyst dosage of 15 g/L), the cyanide removal efficiency exceeded 98%. The catalyst maintained its activity over three successive reaction cycles, indicating excellent structural stability and reusability. This work highlights that employing polymeric waste for catalyst fabrication provides an efficient, sustainable, and low-cost strategy for cyanide remediation, while simultaneously contributing to waste management and environmental protection. Under optimized conditions (pH≈11, ambient temperature, H2O2-to-cyanide molar ratio=3 and catalyst dosage=15 g/L), the cyanide removal efficiency exceeded 98%. The CuO/AC catalyst maintained excellent activity over three consecutive cycles, indicating good structural stability and reusability. This work highlights a sustainable and economical strategy for cyanide remediation using polymer-derived CuO/AC catalysts, simultaneously addressing waste management and environmental protection.
