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Sulfamethoxazole (SMX) is a typical antibiotic in the world, which is frequently detected in the aquatic environment. The current study was aimed to investigate the SMX degradation in secondary treated wastewater using potassium Ferrate [Fe(VI)]. The effects of various experimental conditions, EDTA and phosphate as chelating agents, and toxicity assessment were also considered. Secondary treated effluent was spiked with predefined SMX concentrations, and after desired reaction time with Fe(VI), residual SMX was measured using HPLC. Results indicated that SMX degradation by Fe(VI) was favored under acidic condition, where 90% of SMX degradation was achieved after 120 min. Fe(VI) and SMX reaction obeyed first-order kinetic; meantime, the SMX degradation rate under pH 3 was 7.6 times higher than pH 7. The presence of phosphate (Na(2)HPO(4)) and EDTA declined SMX degradation, while Fe (III) effect was contradictory. In addition to promising demolition, 10% TOC removal was achieved. Eighteen major intermediates were identified using LC-MS/MS and the degradation pathways were suggested. Transformation products (TPs) were formed due to hydroxylation, bond cleavage, transformation after bond cleavage, and oxidation reactions. The ECOSAR analysis showed that some of the SMX oxidation products were toxic to aquatic organisms (fish, daphnia and green algae). GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-021-00769-9.

Systematic reviews are a more complete, repeatable, and less biased form of literature reviews leading to evidence-based conclusions. A systematic review was conducted on articles that have investigated the trade of virtual gray water (VGW) and its effect on freshwater pollution in importer and exporter partners. Scopus and ScienceDirect databases were searched for journal articles covering VGW trade on global, international, and national scales. The relevant articles then were selected and using snowball approach led to more relevant articles. Then, the required data were extracted and recorded. A total of 34 articles met the inclusion criteria, of which 13 articles studied VGW trade on a national scale, 13 on an international scale, and the rest on a global scale. The present study developed a critical appraisal tool to evaluate the methodological quality of the included articles. The results of the critical appraisal showed that none of the included articles can undergo quantitative synthesis. Research gaps regarding VGW trade were observed in the water-scarce developing countries that need to be covered. One of the policy implications to reduce pollution impacts on water bodies would be agricultural and industrial reforms by VGW exporters. Besides, changes in economic structure in both sides of the trade, and goods or water consumption patterns, especially by VGW importers, can also play an important role in water resource conservation. Therefore, international and multi-stockholder cooperation should be taken to alleviate the environmental impacts of the VGW trade.

The aim of this study was to investigate the influence of the CrossFit training on cardiovascular risk factors in overweight men. Twenty-six overweight men (age, 21.6 ± 1.6 years; weight, 86.6 ± 13.1 kg; height, 176.1 ± 6.28 and BMI, 27.8 ± 3.17 kg m2) were randomly divided into two groups of CrossFit (n = 14) and control (n = 12). Subjects in CrossFit group performed five sessions of CrossFit training per week for 4 weeks; while, subjects in control group had no regular exercise. Exercise session included continuous all-out cycling, burpee and squat exercises. Body composition, maximal oxygen uptake (VO2max), anaerobic performance, blood pressure (BP) and lipid profile were assessed in the both groups before and after training. Data analyses showed that weight, BMI, body fat percentage, resting heart rate, diastolic BP, VO2max, peak and average power, triglyceride (TG), low-density lipoprotein (LDL) and LDL–high-density lipoprotein (HDL) ratio significantly improved in CrossFit training in comparison to control group. However, waist, hip and thigh circumferences, waist–hip ratio, systolic BP, HDL and very-low-density lipoprotein (vLDL) were not significantly different between groups (P > 0.05). It is concluded that 4 weeks of CrossFit training induces considerable changes in body composition, physical fitness and lipid profiles (except for HDL) in overweight people.

Municipal water resource recovery facilities (WRRFs) are important sources of antibiotic-resistant bacteria and genes (ARB and ARGs). In this study, antibiotic-resistant total heterotrophic bacteria (THB

Exposure to airborne particulate matter (PM) can be considered as an important risk factor for human health. Some cytokines have been recognized as the biomarkers of exposure to air pollution. Experimental studies indicate that PM exposure could be associated with inflammation. Thus, the purpose of this study was to evaluate whether the exposure to air PM is associated with biomarkers of inflammation. The specific aim of this study was to determine the correlation between airborne PM levels and IL-6 and TNF-α as airway inflammation biomarkers among two groups of late adolescents in northwest of Iran. This study included 46 subjects, comprising 23 asthmatic subjects and 23 non-asthmatic persons. Environmental PM (PM

The performance of ozonation for the removal of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) using Escherichia coli and Pseudomonas aeruginosa carrying ARGs from hospital wastewaters was evaluated in this study. Bacterial inactivation was determined using plate count methods and real time PCR for ARG damage (Sul1, blatem, blactx, blavim and qnrS). The reduction rate of bacterial cells and ARGs was increased by different amounts of transferred ozone dose from 11 to 45 mg/L. The concentration of 108 cfu/ml bacteria was reduced to an acceptable level by ozone treatment after a 5 min contact time, Although the removal rate was much higher for concentrations of 106 cfu/ml and 104 cfu/ml bacteria. Overall, the tendency of gene reduction by ozonation from more to less was 16S rRNA > sul1 > blatem > blactx > qnrS > blavim. Given that plasmid-borne ARGs can potentially be transferred to other bacteria even after the disinfection process, our results can provide important insights into the fate of ARGs during hospital wastewater ozonation.

Background Antibiotics are extensively discharged into the environment through sewages. These emergent contaminants cause health and environmental risks by toxicity, allergic impacts, non-biodegradability and more importantly advancing antibiotic resistance. Antibiotics are hardly removed by conventional treatment processes and frequently are being reported in aquatic environments. The systematic review outlined in this protocol will compile and synthesize literature on the variety and concentrations of antibiotics in wastewaters and receiving water resources. Also, the review will address the efficiency of treatment processes in elimination of antibiotics from aqueous solutions. Outcomes of the study could help wastewater treatment plant engineers with providing reliable design data and outline a road map for future researches. Methods The review will be performed according to the Collaboration for Environmental Evidence (CEE) guidelines for systematic review and evidence synthesis in environmental management, and will be reported according to ROSES reporting standards for systematic evidence syntheses. The published articles will be screened by considering the defined inclusion and exclusion criteria at the title, abstract and full-text levels. Included studies will be exposed to a critical appraisal for validity and quality assessment. The articles will be assessed on the susceptibility to bias and the studies with high bias will be excluded from the data synthesis. The data from included studies will be combined into a narrative synthesis. Random effect Meta-analysis will be conducted due to the likely range of underlying effects. If the heterogeneity exists, the source of heterogeneity will be sought by met-regression and subgroup analyses.

Corrosion and scaling is one of the most important factors influencing drinking water quality that cause health disorders and economic problems. The aim of this study was to evaluate these phenomena in two sources of surface (Makou city) and ground water (Khoy city) in water networks. Corrosion and scaling potential was surveyed by Langelier, Ryzener, aggressiveness, Larson and Puckorius Indices and with measuring water physical, chemical, and microbial parameters. Statistical paired samples t-test displayed significant difference in means value of Langelier, Ryzener, Puckorius indices between cold and warm seasons of the year in Khoy samples and significant difference in means value of Ryzener, Puckorius and aggressiveness indices between cold and warm seasons of the year in Makou samples (p-value

Ozonation (O3) and activated carbon catalyzed ozonation (ACCO) processes were compared in terms of reducing chlorophyll a, turbidity, UV254 absorbance, dissolved organic carbon (DOC) and color from eutrophic water. For ACCO, the average removal efficiency for chlorophyll a of 90.5% was achieved at an ozone dosage of 0.2 mg L−1. The percentage removed increased to 95.8% at higher ozone dosages. The average residual chlorophyll a concentration in the outlet of the O3 and ACCO columns was 9.7 and 4.7 μg L−1, respectively. O3 exhibited an approximately 36% increase in DOC concentration at an ozone dosage of 0.5 mg L−1, while ACCO resulted in 53.5% and 76.0% DOC removal at ozone dosages of 0.5 and 1.0 mg L−1, respectively (DOC residual

Background: The management of construction and demolition (C&D) waste is among the fastest-growing concerns in Iran. Moreover, the basic prerequisites for the effective performance of every waste management program are the accessibility of adequate and precise data on characteristics and its current management condition. Objectives: Estimating the amount of C&D waste in Tabriz metropolitan city (Iran) was one of the key aims of the current study. Another objective of this study was to evaluate of C&D waste handling and their final disposal. Methods: The C&D waste generation rate was estimated according to the waste weight per area of construction and demolition in Tabriz. Then the C&D waste management condition was assessed using a checklist, visiting the disposal site, intervening authorities, and analyzing scientific databases. Results: The amount of C&D waste generation rate in the Tabriz city was estimated to be in the range of 167034 to 848480 ton/year or 0.114 to 0.534 ton/year per capita and 2.267 ton/m2 of demolition. In this area, like most other parts of the country, no scientific and systematic program was observed for source reduction (reduce, reuse, and recycle of the C&D waste). Due to the non-availability of any standard disposal site, all the C&D waste (except for some recycled items such as metals) were deposited at the nearest distance from the city in public lands, waterways, valleys, roadsides and so on. Conclusions: According to the findings there is a great urgent need for applying specific practical policies, rules, and regulations for source reduction (reduce, reuse, and recycle (3R)) of C&D waste. Moreover, a central disposal site should be allocated to dispose of the remaining C&D waste according to the environmental and health considerations.

Chlorpyrifos (CPF), as a highly toxic pesticide, is extensively consumed in the agricultural industry and may cause environmental damage. The aim of present study was to evaluate the potential usage of Fe(VI) and Fe(VI)/PMS processes for CPF oxidation in an aqueous solution. The study was conducted in two phases including coagulation and flocculation, as well as advanced oxidation process (AOP). In the first phase, the coagulation process, as a prevalent pretreatment for AOP, was performed for turbidity removal by two types of coagulants, K 2 FeO 4 and FeCl 3. K 2 FeO 4 showed the best performance as a coagulant at acidic pH=3.0 with an efficiency of 97.47%, while FeCl 3 revealed the highest efficiency (95.79%) at alkaline pH=8.01. However, only the supernatant from the Fe(VI) coagulation process was selected for the next phase analysis. In the next phase (AOP), the results showed that the removal efficiency of Fe(VI)/PMS system was higher than that of Fe(VI) process within the entire pH range. Under optimum conditions ([Fe(VI)]:[PMS]=5:1, pH=7.0, and CPF=2 mg/L), 94.75% removal efficiency was achieved by Fe(VI)/PMS, while it was 82.80% for Fe(VI) alone. The CPF degradation pathways using Fe(VI)/PMS process were proposed, including the P=S bond oxidation, the C–O bond cleavage, diethylation as well as reaction of hydroxyl substitution, leading to the generation of six products. The ECOSAR simulation program showed that the chronic and acute toxicity of CPF degradation byproducts in the Fe(VI)/PMS system relatively decreased. In summary, the study indicated that the Fe(VI)/PMS oxidation is a compatible and efficient technique for removing CPF from aqueous media.

This paper proposes a new double-input Z-network for application in wind energy conversion system (WECS) which is composed of two same DC voltage sources as input sources, two inductors and one capacitor. As a result, the presented structure requires less capacitor number compared to traditional Z-network and it will be able to deliverer energy of both DC sources to local load or grid. The proposed inverter is applicable in dual-star PMSG based WECS, since it requires two DC voltage sources in same value. Besides, dynamic modeling of dual-star PMSG is presented to analyze proposed WECS connected to grid which employs dual-star PMSG and double-input Z-source inverter. The proposed dual-input Z-source inverter controls maximum power point tracking (MPPT) and delivering power to the grid. Therefore, other DC–DC chopper is not required to control two sets of rectified output voltage of generator in view of MPPT. As a result, the proposed topology requires less power electronic switches and the suggested system is more reliable against short circuit. The ability of proposed WECS with dual-star PMSG and double-input Z-source inverter is validated with simulation results and experimental tests using PCI-1716 data acquisition system.

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.

Comparative study of Reactive Blue 194 (RB194) degradation using activated carbon catalyzed ozonation (ACCO) as a hydroxyl radical-based advanced oxidation processes (HO -AOPs) and single ozonation (O3) processes was investigated in this study. Furthermore, the effect of chloride ion (Cl−) on the dye reduction and mineralization was evaluated at different pH values. ACCO was more successful in the reduction of UV254 absorbance and chemical oxygen demand (COD) removal. In ACCO, the dye reduction was marginally increased with adding NaCl concentration from 5 to 50 g/L; while in O3 process, no significant differences were found. In ACCO, higher dye removal rate could be attributed to the production of reactive chlorine species. The results exhibited that temperature elevation promoted color, aromaticity, and COD removal in the ACCO process. Regeneration of activated carbon by ozone modified surface characterization through addition of acidic oxygen groups. In summary, the ACCO process can be suggested as a promising technology for dye removal from saline industrial wastewaters.

Feasibility of iron shavings (Fe0) as a low-cost catalyst was evaluated in catalytic ozonation for degradation of sulfamethoxazole (SMX). The characterization of the catalyst studied by a variety of techniques like scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR). Experimental results indicated a first order kinetics for Fe-based catalytic ozonation (O3/Fe0) and sole-ozonation (O3) in the removal of SMX with slightly greater rate constant for O3. In the both processes, the removal efficiency of SMX was more than 99% at the first 5 min. Average COD removal efficiency in the O3/Fe0 process was about 1.36 times greater than O3. The main intermediates detected by LC-MS/MS were 3-Amino-5-methylisoxazole, benzoquinone, sulfanilic acid, hydroxyl-SMX and nitroso SMX. The mineralization of SMX significantly increased concentration of sulfate and nitrate. Fe0 enhanced ozone utilization and transfer rate. Fe0 is not requiring any preparation before use and could be a promising catalyst for practical advanced wastewater treatment.

Solid waste management and disposal are a global challenge. Also, in spite of rapid urbanization over recent decades, about 47 % (3.31 billion) of the world’s population and 31 % (23.59 million) of Iran’s population are still living in rural areas. Nevertheless, survey on characterization, quantification, and management of rural communities’ household solid waste is rare in both developed and developing countries. Therefore, determining the quantity and quality (composition) of household solid waste of rural communities in the northwest of Iran was the main objective of the present work. The result showed that the average daily per capita of household waste generation was 0.259 kg/cap-day. About 50.98 % of total generated waste in the studied villages was organic and food waste, while paper and cardboard, plastics, metals, rubber, textiles, glass, woods, and other waste materials constituted 6.07, 13.58, 0.47, 1.57, 12.53, 2.09, 0.44, and 12.27 %, respectively. Bulk density of the waste was determined as 211.31 kg/m3. In addition, moisture content and chemical characteristics (food and organic fraction) of the generated waste including the amount of carbon, nitrogen, phosphor, and ash were 57.05, 54.02, 1.74, 0.34, and 34.07 %, respectively. According to the results of this study and the survey in the available related literature, it could be concluded that solid waste generation rates in rural communities are less than that in urban areas and the composition and density of generated waste vary not only between rural and urban areas, but also between different rural communities with various geographical, economic, cultural, social, etc., conditions.

Background: Excessive use of plastic bags has become a major problem in the worldwide causing irreparable damages to the environment and humans. The purpose of this study was to identify the individual and environmental factors associated with the use of plastic bags among the vendors of Hadishahr city, Iran. Materials and Methods: This is a cross-sectional study conducted on 400 vendors working in Hadishahr city. The data were gathered using a researcher-made questionnaire, which measured knowledge and attitudes of vendors regarding the use of plastic bags at the individual level. At the environmental level, access to alternatives plastic bags and social support to use of alternative was measured. Plastic bags in kilograms per week was measured as the consumer behavior Data were analyzed using SPSS software via Chi-square, t-test and hierarchical regression tests. Result: The average usage of plastic bags by the vendors was 4.5 kg per week. 97.8% of vendors gave plastic bags for the customers to carry away their purchased items. The individual-level factors (knowledge and attitude), along with social support for the use of alternatives taken from environmental factors were the most important predictors for the use of plastic bags; they were able to predict consumption behavior (15%) along with other variables. Conclusion: In order to reduce the plastic bags consumption while training, it is necessary to provide social support for the usage of alternatives and environmental access to these alternatives.

Principal component analysis and hierarchical cluster analysis were applied to interpret the results and identify the geochemical process involved in groundwater characteristics in a salt lake basin. All of the water samples were mostly characterized as very hard and brackish water and were Ca-Mg-Na and HCO3-SO4-Cl type. Two principal components were extracted which explained about 82 % of total sample variance. The factor loadings showed that natural processes and contamination from the land simultaneously contribute to chemical faces of the groundwater. Factor score analysis demonstrated three distinct zones that could be linked to different aquifer characteristics throughout the studied area or be recharged from surface water to anthropogenic sources. Three different clusters were obtained which indicated identifiable water quality changes in different zones of the study area. In conclusion, multivariate statistical techniques can effectively provide confidence in delineating and discriminating of natural and non-natural factors governing groundwater chemistry at a shallow alluvial aquifer.

This study combines quasi-Z-source into the five-level inverter using coupled inductors. The suggested circuit consists of only one dc voltage source, one quasi-Z-network, six power switches and only one set of coupled inductors. In this topology, the output voltage amplitude is not limited to dc voltage source and it is reliable and higher efficiency because of quasi-Z-network presence. This study also proposes new switching algorithms for the inverter based on pulse width modulation (PWM) and space vector control (SVC) algorithms, which cause boosting capability of output voltage with low total harmonic distortion (THD). This PWM algorithm is particular one, which calculates dwelling time for each switch in every sample time. The proposed SVC algorithm generates a voltage vector with very low harmonic distortion and reduced switching frequency. The performance of proposed inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system. These results demonstrate the proposed inverter with suggested algorithm can generate a wide range of load voltage.

This study proposes a new topology of cascaded transformer-based multilevel inverter using single Z-source. The suggested circuit consists of only one Z network and one DC voltage source; as a result installation area is reduced. In this topology, the output voltage amplitude is not limited to DC voltage source similar to traditional cascaded transformer-based multilevel inverter and can be increased with Z network shoot-through state control flexibly. Besides, the same as traditional Z-source inverter, it is more reliable against short circuit. Also, a particular switching algorithm has been suggested for presented inverter, which can obtain total harmonic distortion (THD) of output voltage nearly constant for different boost ratio. Moreover, as compared to traditional Z-source inverter, the THD of output voltage is decreased in the suggested topology. The performance of proposed inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system.

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.

Background: Rich texture of cosmetics can provide a suitable medium for growth of pathogenic microorganisms. In addition, skin microflora of anyone is unique which might be harmful to another person. Skin and eye pathogenicity could be communicated by sharing cosmetics in beauty saloons. The main objective of this study was to evaluate microbial contamination of in-use skin and eye cosmetics which are available as public make-up kits for women in the beauty salons. Methods: Fifty-two in-use skin and eye cosmetics were included in this cross sectional study.The specimens from all the cosmetics were collected following the owner’s informed consent,and then about 1 g of the cosmetics was added to nine ml of liquid Eugon LT100 broth medium,two for each product. Ten beauty salons randomly selected from different regions of Tabriz city between June and August 2016. Cosmetics were sampled and carried to the laboratory in sterile condition and then examined to determine bacterial and fungal species in the samples. Results: All of in-use cosmetic were contaminated with bacteria (95% CI = 93.1%-100.0%) and about 19.2% by fungus and yeast (95% CI = 10.8%-31.9%). Streptococcus spp., Pseudomonas spp., Acinetobacter, Bacillus spp., Staphylococcus spp., Escherichia coli, Salmonella, Klebsiella,Citrobacter, Rhodotorula and Candida were dominant species which were isolated from the cosmetics. Powders with 38.5% (95% CI = 17.7%-64.5%) and eyeliners with 30.0% (95%CI = 6.7%-65.2%) were the most fungal contaminated products. Conclusion: Shared cosmetics in beauty salons are almost contaminated by bacteria and fungus.Therefore, it is suggested to avoid sharing cosmetics by women and prevent use of public cosmetics in toilet saloons.

This study presents a new inverter topology based on mixture of cascaded basic units and one H-bridge unit. The basic unit includes one Z source, one DC voltage source and two switches generating two voltage levels. The cascaded basic units produce positive and zero-voltage levels and in the same time suggested inverter obtains positive, zero- and negative voltage levels, as a result the number of power semiconductor switches is reduced with respect to traditional multilevel inverters. In this topology, output voltage amplitude is not limited to DC sources voltage summation similar to traditional cascaded multilevel inverters and can be boosted with Z network shoot-through state control; therefore other DC/DC converters are not needed and it is more reliable against short circuit. Besides as compared with traditional Z -source inverter, total harmonic distortion of injected voltage is decreased in the suggested inverter topology. The performance of proposed topology and its controller are validated with simulation results using MATLAB/SIMULINK software and the validity of the proposed multilevel inverter-based Z source is verified by experimental results.

E-waste is one of the fastest-growing waste streams in Iran, owing to an increase in consumption of electrical and electronic equipment. Nevertheless, as is the case in some other countries, E-waste management has not received sufficient attention. For the successful implementation of any waste management plan (including an E-waste management plan), the availability of sufficient and accurate information on the quantities and composition of the waste generated and on current management conditions is a fundamental prerequisite. At present, in Iran, there is no available and accurate information that describes the characteristics and generation rate of E-waste or the actual practice of management and handling of the waste. For this initial study, eight electronic products were selected for the determination of their E-waste generation rate in the country, and two cities, Tehran and Tabriz, were selected for assessment of the current condition of E-waste management. The study found that the amount of E-waste generation in the country for the eight selected electronic items alone was 115 286, 112 914 and 115 151 metric tons in 2008, 2009 and 2010, respectively. Of the types of electronic items included in the study, televisions, with an average of 42.42%, and PCs, with an average of 32.66% accounted for the greatest proportions of the total mass of E-waste generated during 2008–2010. Currently, despite the fact that primary legislation for E-waste management (as part of general waste legislation) exists in Iran, this primary legislation has not yet been implemented. In practical terms, there is no definite policy or plan for the allocation of funds to prepare suitable equipment and facilities for the management and recycling of E-waste at the end of the products’ useful life. Proposed improvements in current conditions are identified, first by considering other countries’ experiences and then suggesting specific practical policies, rules, and regulations that should be established and applied to all levels of E-waste management. One of the most attractive E-waste management policies is an extended producer responsibility (EPR) programme in combination with a training programme at different levels of society. An approach consisting of a mandated product take back is proposed for implementing EPR in Iran. Meanwhile, the Health Ministry and the Environmental Protection Agency should strictly supervise E-waste collection, storage, and recycling and/or disposal, and the Trade and Industry Ministries must have more control over the import and production of electronic goods.

In the appraisal of head lice outbreak, in addition to socioeconomic factors and availability of health care services, environmental conditions of the households must be taken into account. However, interviewing with children or mailing questionnaires to families may not reflect the actualities. Therefore, in this study, all the inclusive factors which may be associated with head lice outbreak were thoroughly and closely investigated. The data were collected by examining students at schools and surveying patients' households. A questionnaire concerning children's personal hygienic practices, family features, and environmental conditions of the households was filled out during the close assessment of the residential area. The overall prevalence of head lice was obtained as 5.9%, and the difference was not significant within the urban (5.1%) and rural (6.1%) communities. Overall, the number of infested students was more frequent in girls (6.6%) than boys (2.8%), but the difference was not significant. The highest infestation rate was obtained in the examined students whose fathers were unemployed, farmer, and herdsman. Family income showed greater correlation with the prevalence of pediculosis capitis. A high frequency of pediculosis capitis was identified among the students who were sharing individual items with siblings. Assessment of households showed that room flooring material and keeping animals at home were highly correlated with head lice prevalence. Households should be informed that infestations happen, irrespective of socioeconomic status. However, the physical and environmental conditions of living areas and households play an important role in head lice prevention.

Biological treatment of waste gas styrene vapor was investigated in a three-stage bench-scale biofilter. Yard waste compost mixed with shredded hard plastics in a 25:75 v/v ratio of plastics:compost was inoculated with thickened municipal activated sludge. Microbial acclimation to styrene was achieved by exposing the system to an inlet concentration ( C In ) of 0.25 g m −3 styrene and an empty bed retention time (EBRT) of 360 s for 30 days. Under steady-state conditions, maximum elimination capacity (EC) obtained was 45 g m −3 h −1 at a loading rate ( L ) of 60 g m −3 h −1 ( C In of 2 g m −3 and EBRT of 120 s). Reduction of retention time adversely impacted the performance resulting in the maximum EC of 39 and 27 g m −3 h −1 for EBRT of 60 and 30 s, respectively. Evaluation of the concentration profile along the bed height indicated dominance of first-order kinetics at C In ⩽ 0.45 g m −3 and zero-order for higher concentrations.

Two laboratory-scale biofilters filled with the same type of packing material were operated at different gas flow rates and influent concentrations of toluene and xylene in order to investigate their performance in treating waste gas streams. The columns contained a mixture of municipal compost as a base material and wood chips as a bulking agent in an 80:20 ratio; the porosity was 54%. Microbial acclimation was achieved by addition of nutrient-enriched solution along with pollutants for a week by daily mixing and natural aeration. During the start-up of the systems with inlet concentrations of 20 and 70 ppm for toluene and xylene, respectively, high biomass growth resulted in pressure drops in excess of 2000 Pam−1. Under steady state conditions, the response of each biofilter to variations in contaminant mass loading was studied by either changing the influent concentration or flow rate of the inlet waste stream. The results show that organic loading rates of up to 110 and 150 gm−3h−1 can be handled without any indication of the elimination capacity being saturated. However, maintaining the pressure drop below 1000 Pam−1 to avoid operational problems, optimal organic loading rates for toluene and xylene of 78 ± 8 and 80 ± 14 gm−3h−1 respectively are suggested for an HRT value of 60 s. Under these conditions, elimination capacities of 73 ± 4 and 73 ± 14 gm−3h−1 and removal efficiencies of 94 ± 6% and 91 ± 8% were achieved for toluene and xylene, respectively. Copyright © 2003 Society of Chemical Industry

This paper proposes a new topology of cascaded transformer based multilevel inverter using single Z-source. The suggested circuit consists of only one Z network and single DC voltage source, as a result installation area is reduced. In this topology the output voltage amplitude is not limited to DC voltage source and transformers turns ratios similar to traditional cascaded transformer based multilevel inverter and can be increased with Z network shoot-through state control. Besides, it is more reliable against short circuit. In this paper, by using particular switching algorithm, the modulation index of inverter is kept constant and output voltage is controlled by a shoot-through duty ratio, therefore Total Harmonic Distortion (THD) of output voltage is nearly constant for different boost ratio. The performance of suggested inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software.

The effects of leachate recycling and bed mixing on the removal rate of H(2)S from waste gas stream were investigated. The experimental setup consisted of an epoxy-coated three-section biofilter with an ID of 8 cm and effective bed height of 120 cm. Bed material consisted of municipal solid waste compost and PVC bits with an overall porosity of 54% and dry bulk density of 0.456 g cm(-3). Leachate recycling had a positive effect of increasing elimination capacity (EC) up to 21 g S m(-3) bed h(-1) at recycling rates of 75 ml d(-1), but in the bed mixing period EC declined to 8 g S m(-3) bed h(-1). Pressure drop had a range of zero to 18 mm H(2)O m(-1) in the course of leachate recycling. Accumulation of sulfur reduced removal efficiency and increased pressure drop up to 110 mm H(2)O m(-1) filter during the bed mixing stage.

This paper proposes the use of a novel three-phase PWM rectifier-inverter topology for doubly fed induction generator (DFIG) applications. The topology uses only nine IGBT devices for ac/ac conversion through a dc link. As compare to conventional back-to-back ac/ac converters, the numbers of power semiconductor switches are reduced in the suggested converter. The proposed topology results in reduction of installation area and cost. The operating principle, control strategy and characteristics of DFIG based proposed ac/ac converter is described in this paper. The performance of proposed DFIG is validated with simulation results using MATLAB/SIMULINK software.

This paper proposes a new topology of Z-source based cascaded multilevel inverter. In this topology the output voltage is not limited to DC voltage source similar to traditional cascade multilevel inverter and can be increased with Z network shoot-through state control. Besides, it is more reliable against short circuit. Performance of suggested topology in the closed-loop control scheme is described in the Dynamic Voltage Restorer (DVR) structure. Compensation capability of the proposed DVR increases. The operating principle, switching algorithm and characteristics of proposed topology are described in this paper. The performance of suggested inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software.