10 research outputs found

    Top down strategy for renewable energy investment: sizing methodologies and Integrated Renewable Energy System models

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    In this paper, we present a top down strategy for renewable energy investment. The proposed approach is a three-step framework. By applying the approach, renewable energy global market leaders and trends will be identified and analyzed that included: (1) economics and renewable energy policy, (2) specific renewable energy sectors that presents the most attractive investment opportunity, (3) and finally the most promising renewable energy investment vehicles for investors. Other stakeholders can also use the developed framework, such as consumers and policymakers, to make socio-economic decisions and assess renewable energy investments. This paper presents an extensive review on various issues related to Integrated Renewable Energy System (IRES) based power generation. Issues related to integration configurations, storage options, sizing methodologies and system control for energy flow management are discussed in detail

    Removal of COD and TOC From Petroleum Synthetic Wastewater Containing Cyclic Aromatic Hydrocarbons Using the Photo-Fenton Process by the Box-Behnken Method

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    Background: In the last few decades, concern over environmental safety has increased significantly. One of the main causes of environmental degradation is the discharge of untreated pollutants into water bodies. This study examined the efficiency of the photo-Fenton oxidation process to remove chemical oxygen demand (COD) and total organic carbon (TOC) from petroleum wastewater.Methods: Experiments were designed using the Box-Behnken method- a model of the response surface method (RSM) by MINITAB software. First, a wooden chamber equipped with UV lamps installed in the center was applied. The effect of effective parameters on the photo-Fenton process, including naphthalene concentration (10-70 μg/L), pH (2-7), H2O2 (50-800 mg/L), Fe (5-80 mg/L), contact time (10-120 minutes) and UV rays was investigated.Results: The highest removal efficiency of the COD (case 89.27) was at achieved at pH = 2, UV = 24, naphthalene concentration 10 μg/L, Fe concentration 36.06 mg/L, hydrogen peroxide content 800 mg/L, and contact time 120 min. Besides, the highest removal efficiency of the process in removing TOC was 71.04% obtained at 2 pH = 24, UV = 24, and a reaction time of 120 min.Conclusion: Based on the results of this research, the photo-Fenton process has a significant efficiency in removing COD and TOC from petroleum effluents containing cyclic aromatic hydrocarbons and can be utilized as an efficient method for the treatment of petroleum wastewaters

    Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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    Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions

    Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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    Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions. Funding: Bill & Melinda Gates Foundation

    Study the Efficiency of Clinoptilolite Zeolite for Lead Removal from Aqueous Solutions and Determining Adsorption Kinetics and Isotherms

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    Recently the low-cost adsorbent for heavy metals removal such as Lead in recent years has been noticed by researchers. In this study, lead removal by clinoptilolite has been investigated. Non-continuous lead absorption from aqueous solution was carried out by using clinoptilolite. The zeolite characteristics were analyzed with SEM and XRD. The effect of pH variables (1, 3, 5, 7, 10), contact time (15, 30, 45, 60, 90 min), clinoptilolite adsorbent dosage (1, 3, 5, 7, 10 g) and lead concentrations (10, 20, 40, 50, 60, 70, 80 & 100 mg/L) were studied on lead removal efficiency and adsorption isotherms and kinetics in constant temperature and stirrer speed of 250 rpm. According to the results, optimum conditions of lead removal by natural zeolite were pH of 8, adsorbent dosage of 5 g/L and contact time of 45 min., the highest removal efficiency of 89.6 achieved. By increasing metal concentration, the amount of removed lead was decreased while absorption capacity increased. Of the two studied models, the Langmuir isotherm had better conformity for lead adsorption (R2=0.99) than other isotherms. Also the pseudo second order kinetics model had better conformity with achieved data than other models. Results of this study indicated that natural clinoptilolite zeolite can be considered as an efficient and cost effective adsorbent for lead removal from aqueous solutions

    Study of Operational and Maintenance Problems and Parameters of Extended Aeration Activated Sludge Process in Golestan Hospital Wastewater Treatment Plant, Ahvaz, and Their Solutions

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    Background:Hospital wastewater is among hazardous wastewater due to its composition of pathogens and toxic chemicals. Discharge of untreated hospital wastewater to environment is hazardous for human and environment. Aims of this study were to identify Operational and Maintenance problems of Extended Aeration Activated sludge process in Golestan Hospital wastewater treatment plant (WTP), Ahwaz, Iran, and to find their solutions.                                                                   Materials and Methods:Sampling period was 6 months of 2015. BOD5, COD, and TSS parameters analysed in the hospital WTP effluent. In addition, VLR, Qr/Q, MLSS, F/M, SVI, HRT, and θc parameters measured in aeration tank, then operational and maintenance parameters calculated.                                                                                                         Results:Results shown that average of operation & maintenance parameters were: F/M = 0.35, HRT = 6 hour, Qr/Q = 64.28 %, VLR = 1.1 Kg BOD/m3.d, MLSS = 2819.36 mg/l, SVI = 144.89 ml/g, θc = 10.93 days.                                                       Conclusion:Results of operational and maintenance parameters shown that biological process behavior of the hospital WTP was Extended Aeration Activated Sludge in past years, but converted to conventional activated sludge process due to increase in hospital beds of clinical and out patients departments , which increased water consumption lead to increase wastewater flow rate. High flow rate lead to increase hydraulic load and diluting organic matter load, so hydraulic retention time and sludge age decreased

    Study the Efficiency and Effective Factors on the Application of Clinoptilolite Zeolite for Removal of Zn from Aqueous Solutions, Determination of the Adsorption Kinetics and Isotherms

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    Background and objective: The industrial wastewaters are considered to be one of the main sources of heavy metal impurities. The removal of toxic heavy metals from wastewaters is of great importance from an environmental point of zn are the most concerning heavy metals in aqueous solutions due their high toxicity in low concentrations and bioaccumulation in live tissues. Among various removal methods, adsorption through inexpensive adsorbents has been highly considered by researchers. The zn removal by natural clinoptilolite zeolite was defined as the main purpose of the current study. Methods: The experiments were carried out in batch mode operation with natural zeolite. The zeolite characteristics were analyzed with SEM and XRD. The effect of pH (5, 6, 7, 8, 10), contact time (15, 30, 45, 60,90min), adsorbent dosage (1, 3, 5, 7, 10) and pb and zn concentrations (10, 20, 40, 50, 60, 70, 80 and 100 mg/L) on removal efficiency of zn, adsorption isotherms and kinetics were studied in constant temperature. Results: Based on the findings, optimum conditions of zn removal by natural zeolite, included pH, 7, adsorbent dose of 5g/L and contact time of 30 minutes. The metal removal was decreased along with metal concentration, but the absorption capacity was increased. Of the two studied models, the Langmuir isotherm was better fitted Freundlich for zn (R2=0.98). Also for Zn, the pseudo second order kinetics was consistent with results. Conclusion: The results of current study indicated that natural clinoptilolite zeolite can be considered as an efficient and cost effective adsorbent for zn removal from aqueous solutions
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