Search

This study presents the quality of drinking water in terms of salinity in the western margin of Lake Urmia, Iran. During the study a total of 121 samples from 116 wells and 5 springs were collected which constitute drinking water resources of 301 villages in the study area. Approximately more than 30% of the water resources were brackish or saline. The maximum EC is recorded at 3060 µs/cm, which is more than 2500 µs/cm recommended by the European Union. The minimum EC is 410 µs/cm with an average of 980± 495µs/cm. The brackish water resources were located in the northern parts, middle parts and also in the southeast. Unfortunately, in water resources of the study area, salinity seems to be high. This issue should be addressed as a serious concern by managers of water sector.

Exposure to high concentrations of ambient particulate matters (PMs) has a strong potential to cause adverse respiratory outcomes. Recent PMs increase due to the drying of Urmia Lake remains a majo...

The global morbidity and mortality associated with asthma have been dramatically raised. We aimed to determine the prevalence of asthma symptoms in northwestern Iran and identify the potential risk...

Material flow cost accounting analyzes input/output relations of material flows in the production process based on mass balance principles. However, the measured data of a process contains errors representing a mass imbalance in the system such as that of a wastewater treatment plant. Therefore, measured data should be verified before establishing mass balance and, subsequently, material flow cost accounting. Hence, in this work, a novel practical stepwise methodology using data reconciliation technique is introduced to improve the accuracy and certainty of measurements before material flow cost accounting. A full-scale petrochemical wastewater treatment plant was selected to establish this methodology. The presented results of this case study show an error of −3.22% (−35244 t/year) between total input and output streams of wastewater treatment plant demonstrating mass imbalance in the system. However, the overall mass balance could be closed by simultaneously solving the incidence matrix (system of balances). The results revealed that by including data reconciliation into material flow cost accounting, an accurate mass balance can be performed, which is a key element in material flow cost accounting calculations. The comparison results showed a relatively significant difference between material flow cost accounting for reconciled and measured data (unreconciled). The developed approach provides a reliable set of data for implementing material flow cost accounting in the system. Therefore, using this novel stepwise approach will help decision-makers to enhance both financial and environmental performances more confidently and to define appropriate improvement plans.

This study aimed to evaluate the effects of outdoor benzene, toluene, xylenes, and styrene (BTXS) on respiratory system performance in adults living in an industrialized city. The concentration of ...

The performance of a membrane bioreactor treating oily wastewater generated by a petroleum refinery was investigated at mixed liquor suspended solids concentrations of 6.5 and 8.5 g/l with hydraulic retention times ranging from 12 to 24 h. An evolutionary polynomial regression technique and multi-kinetic models consisting of the first-order, Grau second-order, and modified Stover-Kincannon were applied for predicting the performance of the bioreactor. The results showed that a maximum chemical oxygen demand reduction of 97% is achievable at the mixed liquor suspended solids of 8.5 g/l and hydraulic retention time of 24 h. The results also revealed positive influence of higher mixed liquor suspended solids and hydraulic retention time values on the bioreactor performance. In addition, the high accuracy of the evolutionary polynomial regression evidenced its capability in investigating the membrane bioreactor. Based on the analysis performed by the resulted model from the evolutionary polynomial regression, the optimum operating conditions (hydraulic retention time of 21 h; mixed liquor suspended solids of 8.2 g/l) were recommended. According to the kinetic evaluation, the Grau second-order and modified Stover-Kincannon kinetics seemed to be the best approach in describing the chemical oxygen demand reduction in the membrane bioreactor.

The suitability of rural groundwater quality for drinking purposes were investigated in the north west of Iran. Major anions, cations and heavy metals were measured in 39 water wells during the summer and spring seasons . The spatial distribution of major parameters and hydro-chemical faces were described by developing GIS-based maps and Piper and Gibbs diagrams. According to the results, the EC values were in the range of 461 and 2600 μs/cm with the hardness contents between 220 and 720 mg/L as CaCO 3. It was found that, the total hardness is highly correlated with the magnesium concentration than calcium in all samples. The dominant cations and anions were in the order of Mg2+ > Na+ > Ca2+ > K+ and HCO3- > SO42- > Cl- > NO3- > F-, respectively. The major water types in the area were fresh (Ca-HCO3 ) and saline (Ca-Mg-Cl). Based on Gibbs plot, the main mechanisms controlling groundwater chemistry were rainfall dominance, rock weathering dominance, and evaporation-participation dominance. The lower quality of water resources sited in the southern and northern parts of the area was observed according to the GIS maps. It was found that aluminum, boron, iron and manganese concentrations, in some cases, were higher than the guideline values however, it can be concluded that groundwater quality in the study area, apart from some cases, is suitable for drinking purposes without any specific treatment processes. The present study gives a comprehensive status of groundwater quality for proper management in the area.

Volatile organic compounds (VOCs) are common air pollutants that are primarily emitted by motor vehicles and through industrial activity and can have a significant impact on air quality and adversely affect human health. The aim of this study was to characterize benzene, toluene, xylenes and styrene (BTXS) in the ambient air of Tabriz, a city in northwestern Iran, and describe their spatiotemporal variations, ozone formation potential (OFP) and provide a health risk assessment. The measured concentrations of BTXS ranged from 0.46 to 69.32 μg/m3. Diurnal variation showed a significant difference between the morning and evening concentrations, in which the evening values were primarily higher. Spatial analysis showed that the maximum levels of BTXS occurred in the industrial zone. The estimated OFP values ranged from 26 to 418 and 16 to 725 in winter and summer, respectively. In addition, the mean T/B ratio was 1.84, indicating the combustion of fuel in motor vehicles as the main source of VOCs. The hazard ratio of target pollutants was lower than the limits recommended by the USEPA and WHO; however, the estimated lifetime cancer risk for benzene was 7.82 × 10−6, which exceeds the threshold of 1 × 10−6.

Particulate air pollutants are known contributors to global cardiorespiratory mortality through several pathways. We examined the effects of varied exposure to PM

This study assessed the fate of benzene, toluene, and styrene in a full-scale petrochemical wastewater treatment plant (WWTP) with respect to the selection of an efficient and cost-effective control strategy. To prepare input parameters for TOXCHEM, wastewater samples were collected from the inlet of treatment units. Subsequently, the resultant emission rates were applied in AERMOD to study the dispersion patterns of the target volatile organic compounds (VOCs). Based on the TOXCHEM results, the overall emission of benzene, toluene, and styrene was 123,935 g/day, of which 73.4, 13.3, and 13.4% were benzene, toluene, and styrene, respectively. The results indicated that up to 99.5% of the target VOCs were removed from wastewater by volatilization and biodegradation mechanisms. Also, more than 85% of the VOCs emission occurred from the primary treatment units (American Petroleum Institute oil separator, equalization basin, and dissolved air flotation system). In some cases, the concentration distribution profiles resulting from AERMOD showed higher values than EPA reference concentrations (RfC) around the study area. The most affected area was near the WWTP with maximum 1-h concentrations of 8166, 1267, and 1228 μg/m3 of benzene, toluene, and styrene, respectively. Based on the modeling results, the most applicable and available methods for separating and ultimately disposing of VOCs were investigated and compared with the aim of reducing emission rates to meet ambient air quality standards. The results revealed that steam stripping is the most efficient and cost-effective VOCs control strategy in the studied plant. Moreover, thermal incineration was marked as the first choice for ultimate disposal of the contaminated air streams.

The current study investigated the biochemical oxygen demand (BOD) and nitrogen removal from actual municipal wastewater using an up-flow aerated submerged fixed-film (ASFF) bioreactor. The experiments were conducted using a 14.8 L bioreactor with polypropylene packing media. For the first time, three kinetic models (first-order, Grau second-order, and modified Stover-Kincannon) and evolutionary polynomial regression (EPR) were considered in evaluating the substrate removal in an ASSF bioreactors fed with actual municipal wastewater. The applied BOD5 concentrations of actual municipal wastewater varied in the range of 198 ± 12 to 213 ± 16 mg/L. The system was able to achieve a 90%–98% reduction in BOD5, while the organic loading rates (OLRs) were between 0.59 and 2.06 kg BOD5/m3.d. Disregarding certain experimental conditions, the effluent BOD5 concentrations were not more than 20 mg/L throughout the experiments. When the hydraulic retention time (HRT) was reduced from 8 to 2.5 h, the ammonia removal efficiency dropped from 94.0% to 78.9%. Moreover, a direct relationship was observed between the applied OLR and the ratio of volatile solids to total solids. Conversely, an inverse correlation was seen between the reduction in total suspended solids and the OLR. Although several studies have evaluated the aerobic treatment of different kinds of wastewaters, none of the studies contained a kinetic study relevant to ASFF bioreactors treating an actual municipal wastewater. Among the investigated models, the modified Stover-Kincannon and Grau second-order models were found to be the best to describe the present system and well-fitted with the data sets.

Improper solid waste management poses adverse health effects and pollution challenges in both developed and developing countries. The present study is aimed to evaluate the fate of municipal solid waste (MSW) and household waste behaviors in Tabriz megacity. A questionnaire survey was performed to evaluate the knowledge, attitudes and practices of residents toward MSW reduction, source separation, recycling and collection. The results indicated that food wastes make up the highest portion of MSW, and high moisture content of waste leads to low heating value which is below than average heating value for applicability of incineration. Potentially recyclable wastes such as paper and cardboard, plastics, metals, textiles, glass, wood and others make up a total of 33% of the household solid wastes. Investigation of the fate of MSW revealed that about 55.5% of generated waste ends up in landfill sites, 20.5% is separated by itinerant buyers and separation facility just before landfilling, and 24% is converted into compost. The evaluation of resident’s behaviors toward MSW demonstrated the low knowledge of respondents and their high willingness to segregate solid wastes.

Bacteria play a main role in biological wastewater treatment plants (WWTP). Herein, bacterial diversity was characterized in a full-scale WWTP treating petrochemical wastewater containing a wide range of hydrocarbons. Diversity analysis of the activated sludge was carried out using culture-dependent and culture independent methods. From a total of 20 bacterial species identified using 16S rRNA sequence analysis, Brevibacillus parabrevis, Cloacibacterium normanense and Sphingopyxis soli were described for the first time from a petrochemical WWTP. The Shannon diversity index as a measure of bacterial diversity showed decreases from 3.181 to 2.614 during warm and cold seasons. The dominant phyla in all samples was Proteobacteria comprised 63% of the total isolates. Overall, the results showed that the diversity of bacterial communities was higher in warm months rather than cold months. Although, volatilization has usually a significant role on the removal of volatile organics such as phenol, benzene, toluene, and styrene from the liquid phase, the presence of isolated bacterial species indicates their contribution in removal process. Thus, further studies on the capabilities of isolated bacteria in degradation of specific pollutants will be helpful to deepen scientific understanding of biological treatment of difficult wastewaters.

Background This study aimed to investigate the asthma profile among children/adolescents and the relationship of the prevalence of air pollution profiles using latent class analysis (LCA). Objectives In this cross-sectional study, a case rural community was selected in an industrial area, and two rural control communities were selected in unexposed areas. Methods Hourly concentrations of PM10, SO2, NO2, and total volatile organic compounds were obtained from the records of a fixed air quality monitoring station, and the concentrations of benzene, toluene, xylenes styrene were measured during six campaigns. Asthma data was collected using the International Study of Asthma and Allergies in Childhood in 7–18 years old children/adolescents. The modeling was conducted using LCA. Results A higher amount of air pollution indices were observed in the case than both control communities. LCA divided the participants into three clusters; "healthy" (92.8%), "moderate" (2.8%), and "severe" (4.4%). A higher probability of severe asthma (6.8%) was observed in the case than control communities (2.6% and 1.8%). Additionally, after adjusting for possible confounders, the odds of asthma was lower in the control communities than the case in both moderate and sever classes (Odds Ratios in the range of 0.135–0.697). Conclusions This study indicates asthma profiles of children/adolescents and the higher prevalence of severe class in the area, explaining the possible effect of air pollution.

This study aimed to compare the hematologic variables and pro-inflammatory biomarkers in urban adults living in Tabriz, Iran, facing various levels of outdoor volatile organic compounds (VOCs). Of all 219 people (212 male and 7 female), 71 were from the low traffic area and 148 were from high traffic and industrial areas. To validate the exposure levels, 93 air samples were taken to determine the target VOCs (benzene, toluene, xylenes, and styrene collectively called BTXS) concentrations in the studied areas. ANOVA and Tukey's tests were used for statistical analysis. Based on the results, significant differences were observed between the mean concentrations of BTXS with the following order of abundance: industrial > high traffic > low traffic. The Considerable decrease was observed in red blood cells (RBCs), hemoglobin, hematocrit, and eosinophils of 0.324 ( × 106/μL), 0.57 g/dL, 1.87%, and 0.17 ( × 103/μL), respectively in industrial area participants as compared to the low traffic area. However, a significant increase was observed in white blood cell count (WBC), neutrophils number, neutrophils percent, TNF-α and INF-γ of 0.88 ( × 103/μL), 0.80 ( × 103/μL), 3.53%, 34.2 ng/mL, and 40.06 ng/mL, respectively in the same groups. The comparison of low and high traffic areas showed significant differences in RBC (p = 0.034), tumor necrosis factor alpha (TNF-α) (p

Background: The original step in reducing crash severity is recognition of the involved factors. The aim of this paper is to prioritize the factors affecting crashes severity. The current study was carried out in 2018 in Iran. Methods: The present cross-sectional study focuses on factors affecting the crash severity. Due to the complicated nature of traffic accidents, Multi-Criteria Decision-Making methods can be considered as an effective approach. In this work, the factors affecting a crash severity were identified and then attained factors were scored by ten traffic safety experts. To prioritize and weigh these factors, the Analytic Network Process method and Super Decisions Program were used. Results: The results showed four main factors and 60 sub-factors for a crash severity. The main factors in the order of priority were the safety (the most important sub-factor: speed over the upper limit), the other factors (the most important sub-factor: road user type), the health (the most important sub-factor: drowsiness), and the environment (the most important sub-factor: slipping the road). Conclusions: In order to control the crash severity, the presented factors in this study could help traffic safety experts to prioritize and perform controlling actions.

Background: The number of studies available on the performance of on-site medical waste treatment facilities is rare, to date. The aim of this study was to evaluate the performance of onsite medical waste treatment equipment in hospitals of Tabriz, Iran. Methods: A various range of the on-site medical waste disinfection equipment (autoclave, chemical disinfection, hydroclave, and dry thermal treatment) was considered to select 10 out of 22 hospitals in Tabriz to be included in the survey. The apparatus were monitored mechanically, chemically, and biologically for a six months period in all of the selected hospitals. Results: The results of the chemical monitoring (Bowie-Dick tests) indicated that 38.9% of the inspected autoclaves had operational problems in pre-vacuum, air leaks, inadequate steam penetration into the waste, and/or vacuum pump. The biological indicators revealed that about 55.55% of the samples were positive. The most of applied devices were not suitable for treating anatomical, pharmaceutical, cytotoxic, and chemical waste. Conclusion: Although on-site medical waste treating facilities have been installed in all the hospitals, the most of infectious-hazardous medical waste generated in the hospitals were deposited into a municipal solid waste landfill, without enough disinfection. The responsible authorities should stringently inspect and evaluate the operation of on-site medical waste treating equipment. An advanced off-site central facility with multi-treatment and disinfection equipment and enough capacity is recommended as an alternative.

In this paper, the performance of a submerged membrane electro-bioreactor with pre-anaerobic reactors containing anode electrodes (SMEBRþ) was compared with that of a membrane bioreactor (MBR) in municipal wastewater treatment. The new design idea of the SMEBRþ was based on applications of direct current (DC) on the anode and cathode electrodes. The pilot study was divided into 2 stages and operated for 48 days. In Stage I, the MBR was continuously operated for 24 days without the application of electrodes. In Stage II, the SMEBRþ was continuously operated for 24 days, while aluminum electrodes and an intermittent DC were working with an operational mode of 2 min ON/4 min OFF at a constant voltage of 1.4 V. The results indicated that membrane fouling was reduced by nearly 22.02% in the SMEBRþ compared to the MBR. The results also showed that the SMEBRþ increased the quality of effluent to the extent that high removals of NHþ 3 -N, PO3 4 -P, and chemical oxygen demand (COD) were 98%, 76%, and 90%, respectively. This system, in comparison with those proposed in other studies, showed a suitable improvement in biological treatments, considering the high removal of NHþ 3 -N. Therefore, SMEBRþ can be considered as a promising treatment alternative to the conventional MBR.

Background: The measurement data regarding the influent and effluent of wastewater treatment plant (WWTP) provides a general overview, demonstrating an overall performance of WWTP. Nevertheless, these data do not provide the suitable operational information for the optimization of individual units involved in a WWTP. A full-scale evolution of WWTP was carried out in this study via a reconciled data. Methods: A full-scale evolution of acrylonitrile, butadiene and styrene (ABS) resin manufacturing WWTP was carried out. Data reconciliation technique was employed to fulfil the mass conservation law and also enhance the accuracy of the flow measurements. Daily average values from long-term measurements by the WWTP library along with the results of four sampling runs, were utilized for data reconciliation with further performance evaluation and characterization of WWTP. Results: The full-scale evaluation, based on balanced data showed that removal efficiency based on chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) through the WWTP were 80% and 90%, respectively, from which only 28% of COD and 20% of BOD5 removal had occurred in biological reactor. In addition, the removal efficiency of styrene and acrylonitrile, throughout the plant, was approximately 90%. Estimation results employing Toxchem model showed that 43% of acrylonitrile and 85% of styrene were emitted into the atmosphere above water surfaces. Conclusion: It can be concluded that the volatilization of styrene and acrylonitrile is the main mechanism for their removal along with corresponded COD elimination from the WWTP. Keywords: Performance evaluation, Acrylonitrile butadiene styrene (ABS), Petrochemical, Toxchem model

The uncontrolled releases of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) have been highly concerned due to the associated public health risks. In petrochemical industries, WWTPs are responsible for various organic compound emissions into the atmosphere, which can considered as the main source of VOCs emission in such industries. The typical high-strength petrochemical wastewater is generated from an acrylonitrile–butadiene–styrene (ABS) resin manufacturing plant that usually needs pretreatment before discharging to the main WWTP. The objective of this study was to investigate the emissions and fates of acrylonitrile (ACN) and styrene (STM) through wastewater pretreatment units operated in an ABS manufacturing plant. In this study, the emission rates of ACN and STM were estimated by means of EPA’s Water9 emission model. Subsequently, the emission rates were used as the input data of AERMOD model to simulate the atmospheric behaviors of emitted ACN and STM. The results of Water9 model showed that 57 and 81 % of influent ACN and STM are emitted to the air through pretreatment units, respectively. For both of them, the equalization basin had the major portion of emission to the atmosphere. The concentration distribution profiles of ACN and STM resulted from AERMOD model indicted that the concentration of STM was lower than EPA reference concentration (RfC); however, the higher concentration of ACN (higher than RfC) occurred near the WWTP as well as the neighbor ambient.

This study was conducted to evaluate the relationship between air pollutants (including nitrogen oxides [NO, NO2, NOX], sulfur dioxide [SO2], carbon monoxide [CO], ozone [O3], and particulate matter of median aerometric diameter

The presence of pesticides in municipal wastewater and aquatic environments is showing an increasing trend and leading to adverse environmental and health effects. The present study investigated the occurrence of pyrethroids in the municipal wastewater of Tabriz, a city in northwestern Iran. The performance of a wastewater treatment plant for the removal of pyrethroids was also investigated. For this purpose, lambda-cyhalothrin, cypermethrin, permethrin, and deltamethrin in both the influent and effluent of wastewater treatment plant in summer and fall seasons were measured. The toxicity of target pesticides on rainbow trout and Daphnia Magna was also investigated by a new modified index of environmental relevance of pesticides from wastewater treatment plants. The results show that permethrin was the dominant pesticide in the samples in both seasons with the highest detected concentration in the influent wastewater of 1838 ng/L. Furthermore, cypermethrin was among the highly-detected pesticides with concentration as high as 1742 ng/L. It was also found that 77% and 85% of permethrin, as the dominant pesticide, was removed in summer and fall seasons, respectively. Investigation of the risk of pesticides presence in the effluent presents a very high risk to the aquatic environment which was obtained by calculating the proposed index. Although there is a high removal efficiency of pesticides in wastewater treatment plant, higher toxicity and detection frequency of permethrin in the collected samples is the main reason of high risk to the aquatic environment.

Data reconciliation and mass balance analysis were conducted for the first time to improve the data obtained from a petrochemical wastewater treatment plant (WWTP), and the results were applied to evaluate the performance of the plant. Daily average values for 209 days from the inlet and outlet of the plant obtained from WWTP documentation center along with the results of four sampling runs in this work were used for data reconciliation and performance evaluation of the plant. Results showed that standard deviation and relative errors in the balanced data of each measurement decreased, especially for the process wastewater from 24.5 to 8.6 % for flow and 24.5 to 1.5 % for chemical oxygen demand (COD). The errors of measured data were −137 m3/day (−4.41 %) and 281 kg/day (7.92 %) for flow and COD, respectively. According to the balanced data, the removal rates of COD and 5-day biological oxygen demand (BOD5) through the aeration unit were equal to 37 and 46 %, respectively. In addition, the COD and BOD5 concentrations were reduced by about 61.9 % (2137 kg/day) and 78.1 % (1976 kg/day), respectively, prior to the biological process. At the same time, the removal rates of benzene, toluene, and styrene were 56, 38, and 69 %, respectively. The results revealed that about 40 % of influent benzene (75.5 kg/day) is emitted to the ambient air at the overhead of the equalization basin. It can be concluded that the volatilization of organic compounds is the basic mechanism for the removal of volatile organic compounds (VOCs) and it corresponds to the main part of total COD removal from the WWTP.

Natural contamination of surface and groundwater resources with arsenic is a worldwide problem. The present study aimed to investigate and report on the quality of drinking water resources with special focus on arsenic presence in an urban part of Iran. Arsenic concentrations were measured by graphite furnace atomic absorption spectroscopy (GFAAS). In both surface and groundwater samples, arsenic concentrations ranged from 6 - 61 µg/L with an average value of 39 ± 20 µg/L. Concentration of arsenic, which was up to six times greater than guideline values (10 µg/L) indicates the presence of arsenic bearing materials in the geological structure of the region. It was found that the quality of treated surface water produced by the water treatment facility was good in respect to arsenic (9 µg/L) and solid content (EC = µs/cm). However, in drinking water samples of wells, total solids (mean EC = 1580 ± 150 µs/cm), total hardness (mean = 479 + 94 mg/L as CaCO3) and arsenic (mean = 42 + 16 µg/L) were significantly higher. Correspondingly, there was a significant correlation between arsenic concentration and EC, Na+, K+ and Cl- values. The type of water in most of groundwater samples (70%) was determined as HCO3- Na+. Considering the population of the city and probable health effects due to exposure to arsenic through drinking water, comprehensive measures as well as application of arsenic removal processes in water treatment facilities and replacement of contaminated wells with safe wells are required.

Given the importance of groundwater resources in water supply, this work aimed to study quality of drinking groundwater in rural areas in Tabriz county, northwest of Iran. Thirty two groundwater samples from different areas were collected and analyzed in terms of general parameters along with 20 heavy metals (e.g. As, Hg and …). The data of the analyses were applied as an attribute database for preparing thematic maps and showing water quality parameters. Multivariate statistical techniques, including principal component analysis (PCA) and hierarchical cluster analysis (CA) were used to compare and evaluate water quality. The findings showed that hydrochemical faces of the groundwater were of calcium-bicarbonate type. EC values were from 110 to 1750 μs/cm, in which concentration of salts was high in the east and a zone in north of the studied area. Hardness was from 52 to 476 mg/l and CaCO3 with average value of 185.88 ± 106.56 mg/L indicated hard water. Dominant cations and anions were Ca2+ > Na+ > Mg2+ > K+ and HCO3 − > Cl− > SO4 2− > NO3 2, respectively. In the western areas, arsenic contamination was observed as high as 69 μg/L. Moreover, mercury was above the standard level in one of the villages. Eskandar and Olakandi villages had the lowest quality of drinking water. In terms of CA, sampling sites were classified into four clusters of similar water quality and PCA demonstrated that 3 components could cover 84.3% of the parameters. For investigating arsenic anomaly, conducting a comprehensive study in the western part of studied area is strongly recommended.