细化搜索
结果 31-40 的 6,473
Health Impacts Assessment due to PM2.5, PM10 and NO2 Exposure in National Capital Territory (NCT) Delhi
2020
Afghan, F. R. | Patidar, S. K.
The human health impacts caused due to exposure to criteria outdoor air pollutants PM2.5, PM10 and NO2 were assessed in present study. The human health effects associated with exposure to atmospheric air pollution in NCT Delhi were estimated utilizing the AirQ+ v1.3 software tool integrated with Ri-MAP during the study period 2013-2018 considering 80% of the whole population subjected to air pollution exposure. Taking into account the World Health Organization (WHO) (2016) guidelines, the inter-annual average concentrations of PM2.5, PM10, and NO2, concentration response relationships and population attributable fraction (AF) or impact fraction (IF) concepts were adopted. The excess number of cases (ENCs) of Mortality (all) natural cases 30+ years, acute lower respiratory infection (ALRI), lung cancer (LC), ischaemic heart disease (IHD), stroke, incidence of chronic bronchitis in children, postneonatal infant mortality, chronic obstructive pulmonary disease (COPD), prevalence of bronchitis in children, incidence of asthma symptoms in asthmatic children in the year 2013 were 48332, 2729, 5645, 26853, 22737, 120754, 34510, 5125, 9813, 3054, 17203 and 682, respectively. Within half of a decade i.e. in year 2018, the ENCs of Mortality (all) natural cases 30+ years, ALRI, COPD, LC, IHD, stroke, incidence of chronic bronchitis in children, postneonatal infant mortality, prevalence of bronchitis in children, incidence of asthma symptoms in asthmatic children increased significantly and were 72254, 3471, 6547, 7568, 32358, 28233, 150110, 50810, 9019, 862, 29570 and 1189, respectively.
显示更多 [+] 显示较少 [-]O-Anisidine Degradation by Fenton’s Reagent and Reaction Time Estimation
2020
Chaturvedi, N. K. | Katoch, S. S.
O-Anisidines (OAs) are extensively used as an intermediate for chemical reactions to produce various triphenylmethane and azo dyes, and also in manufacturing numerous pigments. They are found to be highly toxic and have carcinogenic properties, so it is imperative to treat OA solutions before disposal. In this study a promising approach to degrade OA solutions has been carried out using Fenton’s reagent. Oxidation trials were conducted for 24 hours and various parameters – OA removal, pH, effect of H2O2 and Fe2+, and COD removal – were analysed to understand the oxidative degradation of OA. For varying initial OA concentrations, the OA and COD removal efficiencies of 72 to 85% and 62 to 74%, respectively, were obtained at pH = 3, and at different optimum H2O2 and Fe2+ doses. Lower initial concentrations of OA showed better removal efficiencies. The reaction time was estimated to 360 minutes after which there was negligible degradation occurs.
显示更多 [+] 显示较少 [-]Removal of Methyl Orange Dye from Aqueous Solution by a Low-Cost Activated Carbon Prepared from Mahagoni (Swietenia mahagoni) Bark
2020
Ghosh, G. C. | Chakraborty, T. K. | Zaman, S. | Nahar, M. N. | Kabir, A. H. M. E.
This study utilized Swietenia mahagoni bark–a wood processing industry waste, for the preparation of activated carbon, and then investigated for the removal of methyl orange (MO) dye by the Swietenia mahagoni bark activated carbon (SMBAC). The effect of pH (3–10), adsorbent dose (1–30 g/L), initial MO dye concentration (10–100 mg/L), and contact time (1–240 min) were evaluated. The surface morphology of the SMBAC was characterized by using fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Maximum removal efficiency of MO by SMBAC was 92%, when initial MO dye concentration was 10 mg/L, pH 3.0, adsorbent dose 10.0 g/L and 120 min equilibrium contact time. The adsorption data fitted well with the Freundlich (R2=0.997) and Halsey (R2=0.997) isotherm models than the Langmuir (R2=0.979) model, and express the multilayer adsorption on heterogeneous surface. The maximum adsorption capacity was 6.071 mg/g. The kinetics data were fitted well to pseudo-second order model (R2=0.999) and more than one process were involved during adsorption mechanism but film diffusion was the potential rate controlling step. The study results showed that SMBAC adsorbed MO effectively, and could be used as a low cost potential bioadsorbent for the removal of anionic dyes in wastewater treatment.
显示更多 [+] 显示较少 [-]Development of Membrane Bioreactor to Membrane Electro-bioreactor for Advanced Treatment of Wastewater
2020
Yeganeh, A. | Nabi-Bidhendi, GH. | Rashedi, H. | Hosseinzadeh, M.
Limited available water resources have rendered wastewater reuse an important issue to specialists in most developed countries, today. The current study works on membrane filtration for treatment of industrial wastewater. By comparing the two methods of membrane bioreactor (MBR) and hybrid membrane electro bioreactor (MEBR) processes, it finds that earlier fouling in the membrane occurs in the first method than the second one. In the membrane electro-bioreactor, in addition to membrane filtration and activated sludge process, the chemical process of electrical coagulation is performed concurrently, wherein the final product quality is improved and the fouling, reduced. In comparison to membrane bioreactor, this method is capable of removing higher percentage of chemical oxygen demand (COD) as an index of organic matters. Accordingly, it is recommended to use the membrane electro-bioreactor method as an alternative to membrane bioreactor for advanced wastewater treatment.
显示更多 [+] 显示较少 [-]Effect of pH, Initial Concentration, Background Electrolyte, and Ionic Strength on Cadmium Adsorption by TiO2 and γ-Al2O3 Nanoparticles
2020
Shirzadeh, M. | Sepehr, E. | Rasouli Sadaghiani, M. H. | Ahmadi, F.
The entrance of Cd (II) to aqueous environments causes a major problem to human health. The current article examines the efficiency of TiO2 and γ-Al2O3 nanoparticles in Cd (II) removal from aqueous medium as influenced by different chemical factors, such as pH, initial concentration, background electrolyte, and ionic strength, in accordance with standard experimental methods. It conducts Batch experiments, fitting various isotherm models (Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich) to the equilibrium data. Saturation indices (SI) of TiO2 and γ-Al2O3 nanosorbents indicate that adsorption is a predominant mechanism for Cd (II) removal from aqueous solution, giving maximum Cd (II) adsorption rates of 3348 and 1173 mg/kg for TiO2 and γ-Al2O3 nanoparticles, respectively, both obtained at the highest pH level (pH = 8) as well as the highest initial Cd (II) concentration (equal to 80 mg/ L). Cadmium removal efficiency with TiO2 and γ-Al2O3 nanoparticles has increased by raising pH from 6 to 8. The Freundlich adsorption isotherm model could fit the experimental equilibrium data well at different pH levels. Also, it has been revealed that cadmium adsorption drops as the ionic strength is increased. The maximum Cd (II) adsorption (1625 mg/kg) has been attained at 0.01 M ionic strength in the presence of NaCl. Thermodynamic calculations demonstrate the spontaneous nature of Cd (II) adsorption by TiO2 and γ-Al2O3 nanoparticles. The former (TiO2) have high adsorption capacities, suggesting they are probably effective metal sorbents, compared to the latter (γ-Al2O3).
显示更多 [+] 显示较少 [-]Chemical Characterization of Particulate Matter at Traffic Prone Roadside Environment in Agra, India
2020
Tiwari, R. | singh, P. P. | Taneja, A.
In the present study, size-segregated samples of PM were collected from urban and semi-urban traffic junctions in Agra, India. PM samples were collected during the monsoon season (July to September 2015) using Grimm portable aerosol Spectrometer. The recorded mean concentration of PM10 at urban site was 137.09±61μg/m3 and at semi-urban site was 270.14±21μg/m3, which were higher than the suggested limits by WHO and NAAQS India. Mean concentrations of PM2.5 were 41.45±40μg/m3, 48.88±34μg/m3 at the urban and semi-urban site, respectively. Whereas, mean concentrations of PM1.0 were 30.35±64μg/m3, 12.64±4μg/m3 and PM0.25 were 0.06±0.05μg/m3, 0.17±0.06μg/m3 at the urban and semi-urban site, respectively. It was estimated that PM10, PM2.5 and PM0.25 values were higher at semi-urban site than urban sampling site but in case of PM1.0 concentrations were higher at urban site. The surface morphology of PM2.5 was studied using Scanning Electron Microscope (SEM). The results show flaky, branched chain like aggregates of carbon bearing spheres at the urban site while cluster, branched, spherical and fluffy particles at semi-urban site. The presences of carbonaceous particles were enhanced due to use of fuel combustion. Chemical analysis was done using ICP-AES. Concentrations of Zn and Cu were found higher while Ni was least in comparison to other metals. Elemental composition present in PM2.5 was used to calculate the health risk assessment to identify the possible health effect on human health, hazards quotient (HQ) values was found higher as Ingestion to inhalation pathways while ECR values found higher as Cr(VI)>Ni>Pb for both medium (Air and Dust).
显示更多 [+] 显示较少 [-]Human Health Risk Assessment of Nitrate and Trace Metals Via Groundwater in Central Bangladesh
2020
Rahman, M. M. | Bodrud-Doza, M. | Muhib, M. I. | Hossain, K. F. B. | Sikder, MT. | Shammi, M. | Akter, R. | Uddin, M. K.
Groundwater plays a pivotal role as the largest potable water sources in Bangladesh. As agriculture is widely practiced in Bangladesh, potential nitrate (NO3¯) pollution may occur. Besides, excess amount of arsenic (As) has already been found in groundwater in many parts of Bangladesh including the present study area. Thus, this study was conducted to assess the NO3¯ status along with some trace metals and associated human health risk in the Central Bangladesh. A total of 99 groundwater samples were analyzed to assess human health risk due to high level of NO3¯ and other trace elements i.e. arsenic (As), iron (Fe), and manganese (Mn). Concentration of NO3¯ was determined using column chromatography and inductively coupled plasma optical emission spectrometer (ICP-OES) was used to measure As, Fe and Mn concentrations. It was found that the mean concentration of NO3¯ 253.17 (mg/L) in the groundwater samples exceeds the recommended guideline value by the WHO (50 mg/L). Moreover, this study area also characterized with elevated concentration of As (19.44 μg/L), Fe (811.35 μg/L), and Mn (455.18 μg/L) in the groundwater. Non-carcinogenic human health risk was calculated by justifying HQ (Hazard Quotient) and HI (Hazard Index) and attributed potential conjunctive human health risks due to NO3¯, As, Fe and Mn in the study area. Child (9.941) is more vulnerable than adult (7.810) considering non-carcinogenic human health risk. Moreover, high carcinogenic risk was found due to As contamination in the groundwater samples and children (1.94×10-3) are more susceptible to carcinogenic risk compared to adults (9.2×10-4).
显示更多 [+] 显示较少 [-]Sustainable Environmental Management using Life Cycle Sustainability Assessment Model in Petrochemical Industry
2020
Maleki, R. | Atabi, F. | Jozi, S. A. | Arjomandi, R. | mansouri, N.
This study aims to present a sustainable environmental model using the life cycle sustainability assessment (LCSA) method in Shazand Petrochemical Company. To determine the evaluation indices, two Delphi and DEMATEL-FTOPSIS questionnaires were distributed among 27 and 8 experts in the field of sustainable environmental management. The environmental, social, economic, environmental-economic, socio-environmental and socio-economic factors were selected as the main criteria based on the previous studies. Data analysis was performed using the DEMATEL-FTOPSIS approach. The values of the determined indices were specified by this study, and the management of the company was prepared. The indicated that the BOD/COD output from the company with the value of 2.181 has the highest effectiveness. Moreover, the index of having short - and long-term planning for local sustainable development with the value of 2.416 had the highest influence. Identification of powerful, strategic and high-quality contractors to enter a long-term contract with them in order to get the competitive advantage in the value chain of the company with the value of 0.569 was found to be the best strategy. Eventually, the sustainable management model for petrochemical industry was presented based on the output results. In this model, indices, prioritizing improvement plans and assessing life cycle sustainability were identified as the most important factors among others.
显示更多 [+] 显示较少 [-]Utilization of Algal Consortium to Produce Biofuels and Byproducts For Reducing Pollution load
2020
Singh, P. | Srivastava, A. | Srivastava, N. | Sharma, V. | Ghildyal, D. | Upadhyay, A. | Singh, P.
Algal biorefinery process utilizes every component of algal biomass to produce multiple useful fuel products. In this technique, acid pretreatment of algal biomass hydrolyzes microalgal carbohydrates into fermentable sugars, makes lipids more extractable and a protein part accessible for additional products. In the present study, Chlorella sorkiniana produced higher quantity of biodiesel than Botryococcus braunii and biomass in Botryococcus braunii was higher than the Chlorella sorkiniana. Botryococcus braunii produces 11% more lipid content than Chlorella sorkiniana which was consistent with biomass content. The total sugar (oligomeric and monomeric) yield attained by Combined Algal Processing (CAP) was 89.9%. 29 g/L ethanol was produced during the fermentation in the Pretreated Algal Slurry. The recovery of lipids from CAP was reported as 84–89% after fermentation and ethanol removal. CAP preserves the PUFA (Poly-Unsaturated Fatty Acids) and utilizes these high-value PUFAs to further reduce the cost of biofuel production and replace petroleum products.
显示更多 [+] 显示较少 [-]Effective Factors in Municipal Solid Waste Minimization and Recovery by Making Use of Citizens' Participation; Case Study of a District in Tehran City
2020
Koushki, B. | Nasrabadi, T. | Amiri, M. J.
The purpose of this research is to quantify the potential of waste recycling in the form of participatory scenarios for separation from the source and to study the factors of minimization (reduction) of waste production in a district of Tehran. Amount of waste minimization was determined with considering a couple of citizens' participation scenarios. Source separation of valuable wastes including paper and cardboard, plastic, plastic bags, aluminum cans, bread, PET, waste metal and glass were considered in this procedure. Among 250 tons of generated dry waste within the district, 150 tons (60%) goes directly to landfill instead of getting recycled. Considering the successful experiences regarding the use of reverse vending machine (RVM) in recycling of beverage containers, this research takes RVM as a reasonable method to promote the recycling activities by citizens. In the 10% scenario, the participation for the separation of the total amount of daily materials is about 4,300 USD per day and in the 25% scenario, 10,800 USD of added value have been calculated. Also, for the participation of 10 and 25 percent during a month, 15 and 30 waste disposal services to the disposal and processing complex could get less.
显示更多 [+] 显示较少 [-]