The ozonation effect on flocculation and polymer consumption reduction in the hybrid treatment of Iran Central iron ore companies' effluent: a cost–benefit study

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

Assessment of aflatoxin exposure using urine biomarker in pregnant and non-pregnant women in Yazd, Center of Iran

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

Application of Chemical Coagulation Process for Direct Dye Removal from Textile Wastewater

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

Biodegradation and nutrients removal from greywater by an integrated fixed-film activated sludge (IFAS) in different organic loadings rates

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