Eleoven Arias-Aguila, Rosemary Vela-Cardich, Lia Ramos-Fernandez
La cuenca baja del río Lurín es una de las últimas grandes extensiones de áreas verdes en Lima, capital de Perú, sin embargo es afectada por diversas actividades antrópicas. Ante esta situación, y con el objetivo de mejorar el manejo de los recursos hídricos, se implementó un modelo de calidad del agua con el módulo GESCAL del sistema de soporte a la decisión AQUATOOL. La construcción de la red hidrográfica del río se hizo a partir de los datos recogidos en salidas de reconocimiento, mientras que para modelar la calidad del agua del tramo bajo del río se desarrolló un programa de monitoreo que tuvo como principales parámetros al oxígeno disuelto, DBO5 y Escherichia coli. Con la información obtenida se determinaron primero los coeficientes de degradación de materia orgánica, desoxigenación y reaireación de las secciones del río, y finalmente se parametrizó el modelo. La calibración del modelo en oxígeno disuelto obtuvo un rendimiento de “bueno” a “muy bueno”, con valores de 0.77, 0.23 y 0.8058 para E, RSR y r2, respectivamente; para el caso de la DBO5, se obtuvieron valores de 0.99, 0.01 y 0.9995 para E, RSR y r2, respectivamente; y para la Escherichia coli, valores de 0.99, 0.01 y 0.9993 para E, RSR y r2, respectivamente. Finalmente, se simularon cuatro escenarios, a partir de los cuales se determinó que para alcanzar los objetivos ambientales es necesario mejorar los procesos de las plantas de tratamiento de aguas residuales (PTAR) Manchay y San Bartolo; clausurar el canal de regadío proveniente de la capilla de la zona, e implementar una PTAR en el distrito de Pachacámac. El estudio demuestra la utilidad del sistema AQUATOOL/GESCAL en la toma de decisiones informadas para la gestión de los recursos hídricos a nivel de cuenca.
Hydraulic engineering, Water supply for domestic and industrial purposes
Abstract The constantly evolving and growing global health crisis, antimicrobial resistance (AMR), endangers progress in medicine, food production, and life expectancy. Limited data on population-level prevalence, including seasonal and temporal variations, hampers accurate risk assessment for AMR transmission, despite its paramount importance on both global and national fronts. In this study, we used quantitative real-time PCR (q-PCR) to analyze 123 antibiotic resistance genes (ARGs) and 13 mobile genetic elements (MGEs) in wastewater of a selected urban community. Sampling was conducted monthly over a 5-month period (December 2021–April 2022) to assess resistance diversity, temporal dynamics, co-abundance of ARGs, MGEs, and resistance mechanisms. Approximately 50% of the tested ARG subtypes were consistently detected in all months, with frequency ranging from 52 to 61% with maximum absolute abundance in the winter months (December and January). In co-abundance analysis, specific genes were clustered into modules, highlighting shared distribution patterns and functional associations among the ARGs and MGEs. Detected clinically significant genes (ndm-1 and cfiA) and other variants (blaoxy, aph, aacC, tet-35, tet M, tet-32) are capable of imparting resistance to 3rd and 4th generation (gen) β-lactam, aminoglycoside, tetracycline, and multidrug classes. These contribute significantly to core/persistent resistance. This study deepens our comprehension of temporal/seasonal fluctuations in ARG and MGE distribution, providing valuable evidence to guide AMR control policies and promote responsible antibiotic/antimicrobial use for preserving effectiveness.
Abstract This study aimed at the valorization of the abundant and underutilized Casuarina equisetifolia fruit waste (CEFW) biomass as an intact easily separable biosorbent for the treatment of dye-polluted water. The intact CEFW was chemically modified to improve its selective biosorption of MB, or to simultaneously remove MB and MO. H2O2 treatment increased the surface functional groups, created pores, and enhanced the selective biosorption of MB. CTAB treatment introduced quaternary ammonium groups and enabled the simultaneously removal of MB and MO. The biosorption of MB by H2O2-treated CEFW was optimum at pH 6 and increased with the mass of the biosorbent. The pH can be adjusted to enhance the biosorption efficiency of the CTAB-treated CEFW toward MB or MO. pH 6 achieves balanced simultaneous removal of MB and MO. The kinetic and isotherm studies revealed that electrostatic interactions and chemisorption dominate the biosorption process which has multilayer character. The single and binary isotherm studies demonstrated that the co-existence of MB and MO enhances their removal. Overall, the modification of the CEFW can be tuned to remove anionic, cationic dyes or both simultaneously and synergistically. The low-cost and easy separation nominate the application of the intact CEFW for dyes removal from polluted water.
Antibiotics are a large group of emerging organic pollutants with low concentration levels in the water. The presence of antibiotics will affect the ecological environment and human health. The removal of trace organic compounds by graphene oxide (GO) membranes has attracted extensive attention. This study investigated the removal of three differently charged antibiotics by GO membranes and the influence of water quality on the removal of antibiotics. It showed that a crosslinked ethylenediamine-GO (EDA-GO) membrane had better stability and higher antibiotic removal performance than a non-crosslinked GO membrane. Among the three antibiotics, penicillin (PNC) was negatively charged and had the highest removal efficiency due to steric effect and electrostatic repulsion. A low concentration (10 mmol L−1) of Na+ in water could increase the membrane flux but had no significant effect on the removal of antibiotics. Ca2+ could reduce the membrane flux and improve the removal of chloramphenicol (CAP) and PNC. The removal efficiencies of low-concentration antibiotics (500 μg L−1) were higher than those of high-concentration antibiotics (10 mg L−1). Furthermore, the removal of antibiotics under the condition of actual wastewater quality was higher than those in solutions prepared with ultrapure water. The EDA-GO membrane has great potential in the removal of antibiotics in wastewater.
HIGHLIGHTS
The removal of three differently charged antibiotics by GO membranes was studied.;
Crosslinked EDA-GO membrane had higher removal performance and better stability.;
The removal of PNC with a negative charge was higher than CAP and ERY.;
Ca2+ could reduce the membrane flux and increase the removal of antibiotics.;
The removal of antibiotics under the condition of actual wastewater quality was higher.;
Alireza Mahmoudian, Fariborz Yosefvand, Saeid Shabanlou
et al.
Abstract In this study, dimensionless parameters influencing the coefficient of discharge (COD) are found and four different WRELM models are developed. After that, a dataset is created for verifying the WRELM models in which 70% of the data are employed to train learning machine models and the remaining 30% to test them. For the mentioned algorithm, the optimal number of hidden layer neurons along with the best activation function is chosen. Additionally, the best value for the regularization parameter of the WRELM algorithm is computed. By analyzing the simulation results, the superior WRELM model and the variables impacting the COD are detected. The superior WRELM model approximates COD values with the minimum error and the highest correlation with laboratory values. For the superior model, the values of the R, MAE and VAF statistical indices are computed to be 0.994, 0.0004 and 98.662, respectively. The analysis of the simulation results indicates that the dimensionless parameters α and T/B are the most influencing input parameters. The superior WRELM model results are compared with the algorithm, and it is concluded that the WRELM model is noticeably more efficient. For the superior WRELM model, a partial derivative sensitivity analysis (PDSA) is conducted in which as the input parameter α increases, the PSDA value increases as well. Finally, an equation is suggested for estimating COD values.
Abstract The primary purpose of a water supply reservoir is to regular highly fluctuating streamflow for providing reliable water supplies. Reducing water shortage risk for impending droughts is a challenge task in real-time reservoir operation due to future inflow uncertainty. The main aim of this study is to propose risk-aversion optimal hedging scenarios during droughts, which is achieved by a two-stage approach. The water shortage probabilities of future lead times are analytically estimated first, then follows an optimization framework that simultaneously minimizing water shortage probabilities of future lead times and sustaining long-term water supply reliability. With an illustration application of the Nanhua Reservoir located in southern Taiwan, the results indicate that the proposed optimization framework provides an efficient hedging to reduce future water shortage probabilities and mitigate severe water shortages in real-time operation. The proposed optimal hedging scenarios outperforms the rule-curve-based current operation. Further improvements are noted for the time-varying rationing coefficient scenarios than the constant-coefficient scenario and the most favorable scenario is the scenario with the highest time-varying frequency. Using the storage to trigger hedging associated with estimated future lead-time water shortage probabilities as the objective functions, the proposed optimal hedging scenarios are not only risk aversion but also executable in real-time operation during droughts.
The food-energy-water (FEW) nexus provides leeway into the lateral transmission of price volatilities within the sectors. The problem is that any inflationary price tendencies in one of the FEW sectors will have direct and indirect effect on the others. The objective of the study was to ascertain the relationship between inflation in food, energy and water, and determine whether there were spill-overs, in South Africa. Monthly consumer price indices for food, energy and water for the period spanning from January, 2002 to December, 2020, were used. Parsimonious vector autoregressive (VAR) model was used in data analysis. The study found that prior to 2013, inflation rate was higher for food relative to water and energy, respectively. After 2017, water had a higher inflation rate relative to energy and food, respectively. Furthermore, energy inflation had positive impact on both water and food inflation, whilst water inflation also had positive impact on food inflation. The study concludes that there is a nexus in the lateral inflation between food, energy and water. Recommendations include building resilience within the nexus through decoupling food and other sectors from fossil fuel-derived energy. It is needed to strike a balance in biofuel and energy production policy to foster complementarities. Operational efficiencies within the sectors also need to be fostered.
River, lake, and water-supply engineering (General), Water supply for domestic and industrial purposes
Abstract The natural support capacity (NSC) of water resources is a key aspect of the regional carrying capacity of water resources, and it can reflect the quality and quantity of water resources in a region. This paper aims to evaluate the NSC of water resources using a model based on the principal component analysis (PCA) to benefit the development and utilization of regional water resources. A case study in the Fuyang district, Zhejiang Province, China, was carried out. First, water resources, as dependent variables, were assumed to be linearly influenced by the indicators affecting the NSC of water resources. These indicators were regarded as independent variables for multivariate analysis in this study. Then, the available water resources data for the Fuyang district between 1995 and 2003 were inputted to the model to analyze NSC levels of water resources. The results indicated that the most important parameters influencing the NSC of water resources could be shortlisted to water resources availability, surface water resources, groundwater resources, allowable withdrawal of water resources, and emission intensity of chemical oxygen demanding. Our findings revealed that the NSC of water resources in the Fuyang district fluctuated between 1995 and 1999 and generally declined after 2000, indicating that the issue of water pollution has worsened since 2000. These results are consistent with the field observations and thus shall provide new potential applications of a PCA-based model in evaluating the NSC of water resources and the relevant water resource carrying capacity for similar areas.
Javad Abdollahi garekand, Ebrahim Sepehr, Vali Feiziasl
et al.
The application of residues of agricultural products as low-cost biosorbents for removing heavy metal from water, is particularly appropriate for developing countries. This study was conducted to compare the removal efficiency of lead (Pb (II)) from aqueous solutions with initial concentration of lead (0- 100 mg/L) by some raw (unmodified) biosorbents (sunflower stalks, wheat straw and corn stalks) and chemically modified of these biosorbents with NaHCO<sub>3</sub> 0.5 mol/L and NaOH 0.5 mol L. Also in this study, lead adsorption isotherms and lead removal efficiency by these biosorbents was investigated. Biochemical composition analysis of the studied biosorbents showed that sunflower stalks had the highest cellulose, lignin and ash content. Hemicellulose were highest in wheat straw but lowest in sunflower stalks. Langmuir and Freundlich models had a better fitness than the Temkin model for removal of lead by unmodified and modified biosorbents. The removal efficiency (RE) for unmodified sunflower stalks, wheat straw and corn stalks were obtained 94-99%, 85-97% and 55-95%, respectively. Also, by modification of biosorbents with NaHCO<sub>3</sub>, the removal efficiency (RE) of sunflower stalks, wheat straw and corn stalks were 94-99%, 85-97% and 55-95%, respectively. Maximum mono layer adsorption (qmax) of modified sunflower stalks, wheat straw and corn stalks increased 293, 305, 394 and 226, 265 and 363 percent compared to unmodified biosorbents, respectively. Separation factor of Langmuir (RL) increased from 0.014-0.73 (for unmodified biosorbents) to 0.065-0.93 (for modified biosorbents by NaHCO<sub>3</sub>) and 0.023-0.56 (for modified biosorbents by NaOH), indicated that the sorption reaction of lead by studied biosorbents are favorable. Chemical modification of the biosorbents with NaHCO<sub>3</sub> could significantly increase the efficiency and capacity removal of lead from aqueous solutions. The ease of preparation of these chemically modified low-cost biosorbents and its high removal capacity for lead makes these biosorbents a good practical candidate for removal of lead from aqueous solutions.
Technology, Water supply for domestic and industrial purposes
Nowadays at the same time with population growth in urban areas, healthy potable water supply has become a challenge especially in arid and semi-aris countries who intend to fulfil a sustainable development. Due to the increasing importance of water treatment and its key role throughout the world, improvement of water treatment plants is becoming more visible. In this research, the criteria and effective factors influencing the quantitative performance evaluation of three treatment plants were investigated using AHP approach. The three treatment plants used in this study were selected from three provences in Iran including Hamedan, Ilam and Kermanshah. The model performance were quantitatively evaluated by using the physical, chemical, and biological characteristics of effluent data. Model performance evaluation revealed that E. Coli; turbidity; ammonia, nitrate and nitrite is most important microbilogical, physical, and chemical water quality parameters when assessing the performance of effluent quality of treatment plants. Based on the the evaluated results, the performance of treatment plants in Kermanshah was better than the other two treatment plants. It will also be equaliy important to indicate that if any of the treatment plants met the effluent standards set by the Iranian authorities.
Technology, Water supply for domestic and industrial purposes
Abstract Karoon River is the most important river in Iran that supplies the drinking and industrial water to many cities and villages in Khuzestan. As a consequence of hospital and municipal wastewater discharge into this river, antibiotic resistance will be increased in microbial inhabitants of this ecosystem. Furthermore, microbial load is also undergone continual variation. The aim of this study was to evaluate seasonal microbial quality and antibiotic resistance in bacterial isolates. For this purpose, five stations were selected and samples were harvested during four seasons. Bacterial count was performed through culturing on Mueller–Hinton agar, and bacterial isolates were identified. Antibiotic resistance profiles of isolates as well as resistance to Hg were investigated. As a result, it was found that the least quality was in summer season while the best quality was in winter that is related to the reduction of water volume and recreational activities in summer and increasing rain and dilution of contaminants in winter season. All isolates were sensitive to Hg while antibiotic resistance and multidrug resistance were found in bacterial isolates. Based on the obtained results, it can be concluded that the microbial quality of Karoon River has variations depending on the season and it is necessary that be monitored in order to control and prevent epidemic bacterial infections and antibiotic resistance distribution.
Abstract The present study explored the feasibility of using derived and thiourea-functionalized silica as adsorbent for the removal of cadmium under different experimental conditions. Effects of various parameters such as function of point of zero charge (pHPZC), solution pH, sorbent-sorbate resident time and ratio, concentration and temperature were investigated. The sorption of cadmium followed the pseudo-second-order rate kinetics. Thermodynamic studies revealed that the sorption of cadmium was endothermic and spontaneous, with good affinity toward the sorbent. Various isotherm models, viz. Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Harkins–Jura, and Halsey isotherms were used to analyze the equilibrium data at different temperatures. The Freundlich, Halsey, Langmuir, and Temkin models were found to be in good agreement with the experimental data with high R 2, low RMSE, and low χ 2 values. The results show that the sorption capacity increases with an increase in solution temperature from 28 to 65 °C. The maximum sorption capacity calculated from Langmuir isotherm was 27.55 and 28.41 mg g−1 for derived and thiourea-functionalized silica, respectively, at optimum condition of pH 5 and contact time of 120 min.
Abstract Carica papaya seeds of a tropical tree comprise water-soluble and positively charged protein known as cystine protease which emerged as a putative coagulant in both water and wastewater treatments. Natural coagulants applications have been posed in many evaluation assays through many years owing to the difficulties raised by usage of chemical coagulants. It is indispensable to optimize process variables such as pH, turbidity, total dissolve solids (TDS), E. coli and coliforms counts accuracy to raise the efficiency of coagulation operation via employing C. papaya. Experimentally, employing jar tests supported by pretreatment, papaya seed protein as a natural coagulant, alum and solar disinfection to remove turbidity and bacteria was accomplished. The results revealed that the removal efficiency for turbidity was culminated up to 100% by incorporation of both alum and C. papaya seeds at lower dosages of coagulant about 0.2–0.6 mg/L at 30 min. A significant difference was found for paired samples correlations around 0.130 by p value = 0, among TDS, C. papaya and alum dosages and turbidity values. Employing a combined process resulted in turbidity and bacteria (most probable numbers of coliforms) removal around 100%. The highest efficiency of solar disinfection system possessed to fell the sunlight exposure period time by up to 2 h with 100% removal of E.coli and coliforms.
Desde que se ha hecho evidente que existe una función de estado j(t) que guía la evolución de las plumas de solutos en los flujos naturales, la naturaleza de esta función ha sido analizada desde diversos puntos de vista (Constaín, 2012). En este artículo se muestra cómo j(t) es universal para todo el flujo en tanto éstos cumplan la condición de “equilibrio dinámico”. Al mismo tiempo se muestra la validez simultánea de la ecuación de Elder en función de j(t), que relaciona el transporte dispersivo con la geomorfología y por lo tanto pudiendo calcularse la pendiente de un flujo en “estado estable”. Se aplica esta metodología a un cauce mediano en Colombia, verificándose que la gráfica de la concentración pico para el trazador es bastante congruente con los datos esperados si se aplican los principios aquí desarrollados.
Hydraulic engineering, Water supply for domestic and industrial purposes
Sayyad Bodaghi, mitra gholami, Mehdi Farzadkia
et al.
Performance of wastewater treatment plants (WWTPs) in Urmia, Khoy, Miandoab, Salmas, and Bookan were evaluated during the years 2008 to 2011 based on the reliability approach. The approach predicts the overall performance of WWTPs and their processes and, thereby, makes the screening of treatment technologies possible. The required BOD5, COD, and TSS data were collected using the records available at West Azerbayejan Water and Wastewater Company, local surveys, and interviews with operators. Statistical analysis was performed by SPSS. The valid Niku modeling was employed to calculate the Rmeasured , Revaluated, COR, and expected percentages of compliance with discharge standards and a significant relationship was found among these parameters. The results also showed the log normal distribution of effluent characteristics. Furthermore,SBR and biolac processes exhibited higher values of Rmeasured (90-100%), Revaluated (93-100%), and expected percentages of compliance with the discharge standards (95-99.97%) in all the WWTPs studied but lower values of COR (0.41-0.64) than those in aerated lagoons. The coefficients obtained in this study can, therefore, be used for the development and construction designs of similar systems.
Technology, Water supply for domestic and industrial purposes