https://www.wwjournal.ir/ Journal of Water and Wastewater; Ab va Fazilab (in persian) en daily 1 Fri, 21 Nov 2025 00:00:00 +0330 Fri, 21 Nov 2025 00:00:00 +0330 https://www.wwjournal.ir/article_242274.html 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. https://www.wwjournal.ir/article_243975.html 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. https://www.wwjournal.ir/article_244963.html 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. https://www.wwjournal.ir/article_245312.html 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. https://www.wwjournal.ir/article_245427.html 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. https://www.wwjournal.ir/article_232578.html 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. https://www.wwjournal.ir/article_234374.html Paved Drying Beds are a sustainable, low-energy technology for wastewater sludge dewatering, but their efficiency is hindered by long drying times and high land requirements, which are highly dependent on climatic and operational parameters. This comprehensive review synthesizes current research on the potential of Artificial Intelligence to optimize PDB performance. A systematic literature review was conducted, analyzing 32 key studies to evaluate the impact of parameters such as sludge depth, type, and climate on drying efficiency, and to assess the application of AI and machine learning techniques for process prediction and control. The thematic synthesis reveals that shallower sludge depths and favorable climatic conditions significantly reduce drying time. AI models, particularly Artificial Neural Networks and Gradient Boosting Machines, have demonstrated high accuracy in predicting complex sludge treatment processes like settleability and production. The review highlights the promise of hybrid models that integrate AI with physical principles to enhance robustness and generalizability. Despite this potential, significant challenges remain, including model-data mismatch, supernatant management, and a lack of real-world validation. This paper identifies critical future research directions, such as the development of real-time monitoring systems, the use of transfer learning to overcome data scarcity, and the creation of digital twins for adaptive PDB operation. By providing a critical framework for AI integration, this review aims to advance the sustainability, cost-effectiveness, and operational efficiency of PDBs within modern wastewater treatment plants. https://www.wwjournal.ir/article_245592.html Accurate determination of flow direction in water distribution networks is a fundamental prerequisite for hydraulic modeling, leakage detection, valve isolation, and network maintenance. While ArcGIS Utility Network Analyst provides robust tools for tree-like (branched) networks, it fundamentally fails to assign determinate flow direction in looped configurations due to the absence of inherent downstream topology. This study addresses this critical gap by developing a novel custom extension, the "Individual Flow Direction Tool," which integrates high-resolution LiDAR-derived digital elevation models with geometric network intelligence to assign flow direction on a per-hydro-edge basis. The research methodology comprises four integrated phases. First, a comprehensive geodatabase was designed incorporating 12 feature classes (pipelines, valves, fittings, hydrants, reservoirs, meter-boxes) with predefined subtypes, attribute domains, and connectivity rules. Second, a 1m-resolution DEM and subsequent 3D surface model were generated from airborne LiDAR data (decimeter accuracy). Third, Z-values were extracted for all junction endpoints using the "Extract Values to Points" tool. Fourth, the IFD Tool-developed as a custom ArcGIS add-in-was programmed to evaluate each edge individually based on the comparative Z-values of its two terminal junctions, iteratively propagating flow determination through complex loop systems. The tool was validated against field-verified flow data from Syarikat Air Johor Holdings for 14 interconnected loops comprising 3.7 km of PVC pipelines (D=150mm, C=150) in Taman Mutiara Rini, Malaysia. The IFD Tool successfully assigned flow direction to 100% of network edges. Comparative analysis revealed 79% agreement (1,428 out of 1,807 edges) between LiDAR-based flow assignments and SAJH field data, with 21% disagreement primarily concentrated within loop interiors rather than source-sink trunks. Hardy-Cross verification confirmed hydraulic balance in all disagreed edges, demonstrating that the Hardy-Cross method can yield multiple valid flow solutions for a given looped network. Consequently, the 21% disagreement does not indicate a methodological flaw; rather, it reflects the existence of multiple hydraulically balanced flow regimes. The SAJH field data captures the specific operational state influenced by undocumented interventions (e.g., booster pumps, partially closed valves), while the IFD Tool provides the topographically natural baseline. This research presents the first documented ArcGIS extension specifically designed for looped-network flow assignment using topographic intelligence. The IFD Tool transforms WDN management by enabling scientific, reproducible flow determination independent of subjective engineering judgment. Based on this specific case study (flat terrain, uniform PVC pipes), the methodology is estimated to reduce utility expenditure on flow direction field verification by 70-80%. However, further validation across diverse topographic conditions and pipe materials is required to generalize this estimate. https://www.wwjournal.ir/article_247238.html 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 and in two seasons, spring and summer 2024, 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. This study, by providing empirical evidence, 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. https://www.wwjournal.ir/article_247566.html 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, due 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 multidimensional 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. https://www.wwjournal.ir/article_248431.html 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. https://www.wwjournal.ir/article_250533.html Membrane separation has been proven to be highly effective in oily wastewater treatment, although fouling remains a persistent challenge. This study explored the incorporation of S-βzeolite nanoparticles into an ultrafiltration membrane, forming a nanocomposite to tackle fouling and enhance water flux recovery. Porous nanoparticles were synthesized using sol-gel and hydrothermal methods, featuring a remarkable surface area of 450 m2/g and pore sizes ranging from 50 to 175 nm according to BET results. These nanoparticles were integrated into the membranes at various concentrations using the phase inversion technique. The presence of S-zeolite in the membrane was confirmed through FTIR, EDX and SEM analyses. The S-β1 nanocomposite membrane demonstrated exceptional antifouling properties, particularly at higher concentrations of oily wastewater. Its outstanding performance is attributed to its enhanced hydrophilicity and average pore size of 13±3 nm, which prevents fouling formation. Compared to other membranes, S-β1 exhibited remarkable water flux recovery, reaching100% at an oil concentration of 50 ppm and 72% at 1000 ppm. These results highlight the significant advantages of this nanocomposite in reducing fouling and improving the water flux recovery in oily wastewater treatment.