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Abstract Today, there is a significant concern in the industry regarding the disposal of wastewater containing dyes into the environment, so the management and appropriate disposal of these wastes in the environment are considerable. The main aim of this study is to assess the efficiency of activated carbon (AC) prepared from sesame shells to remove direct dyes from aqueous solutions. According to the results, AC prepared from sesame shell had a high specific surface area (525 m2/g) and porous structure. The results demonstrated that the adsorbent had high potential to remove direct dyes as 84.5% of direct brown 103 (DB103), 93.08% of direct red 80 (DR80), 93.37% of direct blue 21 (DB21) and 98.39% of direct blue 199 (DB199) under the optimal conditions of adsorbent dose 4.8 g/L, contact time 19 min, pH 3 and initial dye concentration 12 mg/L. The experimental results showed that kinetic data were best described by the pseudo-second-order model (R2 = 0.989) while isotherm data were best fitted by the Freundlich model (R2 = 0.994). In the present study, not only was the produced waste used as a useful and economically valuable material, but it was also applied as an effective adsorbent to remove direct dyes from industrial effluents and reduce environmental pollution.

Introduction: High concentrations of nitrate, nitrite, and fluoride in drinking water can cause adverse health effects. This study aims to investigate concentration and health risks assessment of nitrate, nitrite, and fluoride ions in water reservoirs of Mehriz city and Bahadoran district. Materials and Methods: Monthly sampling was done from water reservoirs of Mehriz city and Bahadoran district for 6 months. Nitrate, nitrite, and fluoride concentrations were measured in the samples using a spectrophotometer. Then, health risk assessment and sensitivity analysis were performed on the obtained data using Crystal Ball software and Monte Carlo simulation method. Results: Nitrate, nitrite, and fluoride concentrations were lower than the standard limitation in all of the studied areas. Risk assessment findings indicated that hazard quotient (HQ) values of nitrite in Miankoh-Movahedin, Bidok and Bahadoran water reservoirs were less than 1 for all age groups. HQ values of nitrate were also below 1 for all age groups except children. HQ values of fluoride in Bahadoran water reservoir were below 1 for all age groups except children. Conclusion: Health risk of consuming water containing nitrates and fluorides is high for children. Based on sensitivity analysis, the concentration of nitrate and fluoride in drinking water is the key factor in raising health risks. Reducing nitrate and fluoride concentrations in drinking water can reduce health risks in the population.

Abstract Sustainable municipal solid waste leachate (MSWL) management requires a paradigm shift from removing contaminants to effectively recovering resources and decreasing contaminants simultaneously. In this study, two types of humic substances, fulvic acid (FA) and humic acid (HA) were extracted from MSWL. HA was extracted using HCl and NaOH solution, followed by FA using a column bed under diversified operations such as flow rate, input concentration, and bed height. Also, this work aims to evaluate efficiency of Artificial Neural Network (ANN) and Dynamic adsorption models in predicting FA. With the flow rate of 0.3 mL/min, bed height of 15.5 cm, and input concentration of 4.27 g/mL, the maximum capacity of FA was obtained at 23.03 mg/g. FTIR analysis in HA and FA revealed several oxygen-containing functional groups including carboxylic, phenolic, aliphatic, and ketone. The high correlation coefficient value (R2) and a lower mean squared error value (MSE) were obtained using the ANN, indicating the superior ability of ANN to predict adsorption capacity compared to traditional modeling.

Abstract This study investigated the performance of continuous-flow electrocoagulation (CFR-EC) reactor for aged landfill leachate treatment with a novel configuration of iron and aluminum electrodes to enhance the applicability of the process. The effects of the applied current density (ACD), initial pH, and hydraulic retention time (HRT) on the percentage removal of COD, TOC, BOD5, color, turbidity, and heavy metals (HMs) were modeled with Box-Behnken design (BBD). The results demonstrated that the models are significant (R 2 0.97—p-value

Abstract Iran's most important iron ore mine is located in the central region, and because of the water shortage in this area, the need to reuse the effluent from this mine is essential. On the other hand, there are no suitable conditions for treating large effluent volumes in iron mine in central Iran. For this reason, produced effluent should be reduced and returned to the consumption cycle by using appropriate technology. This study aimed to investigate the ozonation/lime effect on polymer consumption reduction and evaluate the treatment and economic efficiency compared to the currently used treatment method (coagulation-flocculation without ozonation/lime). The use of ozonation along with the coagulation and flocculation process has been an effective factor in reducing all the studied indicators, which has been a much more significant reduction effect for turbidity (95%), decreasing from 374-350NTU in the non-ozonation process to 110-160NTU, and Chemical oxygen demand (37%). In addition to increasing the treatment efficiency, the hybrid ozonation/coagulation and flocculation process reduced operation costs. The ozonation process caused the high-level conversion of Fe2+ and Al2+ to Fe3+ and Al3+ (> 90%), thus it improved wastewater treatment and increased cost benefit. The hybrid process was affected in improving the effluent quality and reducing the produced sludge volume. The ozonation process caused sludge volume reduction or has photocatalytic effect on it. It effected the micro-sized bubbles production reduction in sludge volume unit. However, estimating the cost–benefit of using this method can be beneficial in making the final decision on whether to use it or not.

Background: Aflatoxins (AFs) are one of the most prevalent toxins, which long-term exposure to them could be a risk factor for liver cancer. AFM1 is the hydroxylated metabolite of AFB1, therefore, the presence of AFM1 in urine samples can give an appropriate estimation of dietary AF exposure in human. Methods: The present study aimed to evaluate the excretion level of AFM1 in urine samples of pregnant and non-pregnant women in Yazd, Iran. A total of 85 urine samples (42 pregnant and 43 non-pregnant) were selected randomly from women who had referred to health centers of Yazd during March to May 2017. From each participant, a 72-hour dietary recall was asked and the data were recorded and later analyzed by ELISA kits. Results: The results showed that the mean level of AFM1 in pregnant and non-pregnant women was 8.23 ± 2.9 and 35.5 ± 1.05 pg mL-1, respectively. Excretion of AFM1 in urine samples had a significant relationship with some demographic factors and type of consumed foods (P < 0.05). Conclusion: There was a significant relationship between the education level, place of residence, and the consumption of nuts with the excretion of AFM1. It can be concluded that some foods distributed in Yazd are contaminated with AFs, and a significant number of people are exposed to high concentrations of AFM1.

Introduction: Water quality is essential for industries because they play an important role in countries’ economic development. Groundwater is one of the most widely used resources, and when the ionic constituents were increasing higher than the allowable limit, it increases the cost of maintenance and production in the industries. Materials and Methods: In order to evaluate groundwater corrosiveness and scaling potential in Zahedan City, 29 groundwater wells and GIS-based geostatistical mapping techniques were analyzed clemically. The physicochemical parameters were invetsiagted and the most popular corrosion and scaling indices were determined as Langelier Index (LI), Aggressive Index (AI), Ryznar Index (RI), Puckorius Index (PI), and Larson–Skold Index (LS). Using ArcGIS 10.6.1 software, the zoning maps were plotted for LI, AI, RI, PI, and LS indices. Results: The results showed that total dissolved solids (TDS) and electrical conductivity (EC) values in all of the samples exceeded the World Health Organization (WHO) drinking water standard. AI values of 58.62% samples showing moderate corrosiveness, and the remaining 17 samples have a scaling nature with very less corrosivity. Based on the LI values, 55.2% of samples have a corrosive nature. Concerning RI values, 59% of the samples have a corrosive tendency. According to the PI values, the entire groundwater of this region has a significant corrosive tendency, and 96% of samples exceeded the LS > 1.2, showing a high rate of localized corrosion. Conclusion: The zoning and spatial analysis of water quality showed that water quality was treated for industrial purposes in the entire studied region.

The entry of toxic organic pollutants and resistant to biodegradation has increased the concern about human health. The use of advanced oxidation (AO) processes to degrade these pollutants has been developing. One of the AO processes is based on the use of hydrogen peroxide in removing resistant organic pollutants.This study aimed to develop a new reactor capable of producing H2O2 in the solution. Therefore, a porous electrode made of stainless steel with the capability of air injection in the electrode center was used. The 30 cm rod graphite electrodes were also used as an anode electrode in a 4000 ml reactor. The effects of variables, including current density (30–40 mA/cm2), time (10–30 min), and electrolyte concentration (12–17 mM/L) on the amount of H2O2 production were evaluated by Box behenken design under response surface methodology using Design expert software. The results of this study showed that H2O2 can be produced at the electrode surface of porous cathode under optimal conditions of 36 mA/cm2 current density, 16 mM/l electrolyte concentration, in 23 min, and in the amount of 34 ppm. Using a porous cathode electrode causes the maximum contact among the solution, water, and air, and increases the production of H2O2.The release of resistant organic compounds to the waste water is a serious problem to the environment. By the application of the Electro-oxidation (EO)reactor with the ability to produce H2O2, this issue is resolved. Furthermore, this technique is applied for non-selective degradation of the toxic organic compounds. • The electro-oxidation process is a useful method for destruction of persistent organic matter from wastewater. • Due to use of porous cathode in this method, contact between the electrode and the sewage is at its maximum level which increases the efficiency and speed of sewage treatment. • This method can produce H2O2 as a high potential oxidant that can reduce persistent organic properties of sewage and make the wastewater suitable for biological treatment. Method name: Advanced Oxidation Process (AOP), Electro-oxidation (EO), Electrochemical Oxidation Processes (EOP), Keywords: Box Behnken design, Electro-oxidation process, Hydrogen peroxide, Modeling, Porous electrode

Abstract In this study, the efficiency of Integrated Fixed-film Activated Sludge (IFAS) system in synthetic greywater treatment and nutrients removal was studied in duration of 105 days according to different Organic Loadings Rates (OLRs). The study was operated in pilot-scale and OLRs of 0.11–1.3 gCOD/L.d. Scanning Electron Microscope (SEM) image showed that the biofilm with a proper thickness was formed on IFAS reactor’s media. The results indicated that the best removal efficiency of BOD5, COD, and TSS were 85.24, 92.52 and 90.21%, respectively, in an organic loading of 0.44 gCOD/L.d. Then, with the OLR increased, the removal efficiencies of BOD5, COD, and TSS increased as long as the organic loading reached 0.44 gCOD/L.d. But with the OLR increased more, the removal efficiency of these parameters decreased. The ANOVA statistical test results showed that the mean difference of removal efficiency in organic loadings for BOD5 (p ≤ 0.001) and COD (p = 0.003) was significant, while it was insignificant for TSS (p = 0.23). The best removal efficiencies of Total Nitrogen (TN) and Total Phosphorus (TP) were 89.60 and 86.67%, respectively, which were obtained at an OLR of 0.44 gCOD/L.d. By increasing OLR up to 0.44 gCOD/L.d, removal efficiencies of TN and TP increased, while the removal efficiency decreased with the OLR increased more, and this difference was statistically significant (p = 0.021). Finally, the results showed that the IFAS system provided a proper efficiency in treatment of the synthetic greywater and it could be used in a full scale.

Introduction: Since some dyes and their metabolites have toxicity and carcinogenicity potential, and are dangerous to the health of different living creatures, discharge of untreated wastewaters containing large concentrations of dye compounds into water resources is one of the important environmental problems. Therefore, in this research, the efficiency of chemical coagulation process was investigated using ferric chloride coagulant to remove Direct Red 23 dye from colored wastewater. Materials and Methods: In the experiments, a Jartest device was used and the effect of different parameters including the dose of the coagulant (20-200 mg/L), pH (3-10), and initial concentration of the dye (25-200 mg/L) on the efficiency of chemical coagulation process for removal of the dye was examined. Further, the final pH of the wastewater was investigated and the optimal conditions were determined. Results: The results indicated that the optimal dose of ferric chloride coagulant for Direct Red 23 dye removal of 97.7% is 40 mg/L at the optimal pH of 7. With increase in the dose of the coagulant, the dye removal efficiency increased, while the final pH of the wastewater decreased. Under constant conditions, with increase in the dye concentration, the dye removal efficiency diminished. Conclusion: Chemical coagulation by ferric chloride is a very effective and fast method for removal of direct dye from colored wastewater.