خيارات البحث
النتائج 51 - 60 من 6,531
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.
اظهر المزيد [+] اقل [-]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).
اظهر المزيد [+] اقل [-]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).
اظهر المزيد [+] اقل [-]A Review of Air Pollution and Solutions Way Management Related to Ribbed Smoked Sheets (RSS) Production of Community-Level Rubber Cooperatives in Thailand: Smoke, Soot and PAHs particles
2020
Kalasee, W. | Teekapakvisit, C.
In Thailand, RSS chamber of community-level rubber cooperatives can be classified into two models: old and new model, named after the years of their establishment. Hot gas as a heat supply from Para-rubber (PR) wood (Hevea brasiliensis) combustion is used for removing moisture from the natural rubber (NR) sheets. Smoke and soot particles from PR wood burning has effected to the quality of the NR sheet and the pollution in the workplace area and lead to health problems of the worker. Cascade impactors are equipment for measuring the smoke and soot particles size distribution from PR wood combustion. PAHs compounds from PR wood combustion were found 15 different PAHs components (Tekasakul et al., 2005; Furuuchi et al., 2006). Important methods in decreasing smoke and soot particles from combustion of PR wood for rubber smoking chamber are separation equipment and ventilation designed by computational fluid dynamics (CFD) technique. In this article, the separation method is focused on smoke and soot particle collection to maintain the quality of the NR sheet. This equipment is reviewed both indoor and outdoor, for example, an impaction wall, electrostatic precipitator, stainless-wire, etc. This review indicates that the ESP installing between the furnace and the smoking chamber is suitable to eliminate aerosol particles at the rubber smoking industry. In addition, CFD technique reports is aimed at collecting aerosol particles for decreasing smoke and soot particles emission from rubber smoking chamber is presented.
اظهر المزيد [+] اقل [-]Overall D. melanogaster Cohort Viability as A Pollution Indicator of the Atmospheric Air of Urban Landscapes
2020
Rudenko, S. S. | Leheta, U. V. | Rudenko, V. P. | Kostyshyn, S. S. | Bialyk, V. D.
The method of air pollution level evaluation of urban landscapes on the basis of D. melanogaster cohort analysis has been suggested. The method implies the binding to the landscape areas of the city. Within each landscape area traps and cultivators for D. melanogaster have been installed in sanitary-protective zones of various enterprises as well as on the background territory with the least level of anthropogenic load serving as the control. Based on specifically elaborated technique for field conditions, the amount of eggs, third instar larvae, pupae and imago has been calculated. Then, using the computer program ImageJ, the square under the curves of cohort survival has been determined which is considered overall cohort viability (OCVD.m). The previously mentioned indicator considers cohort survival at all stages of ontogenesis. In addition, the expressed in percentage indicator of oppression (IO OCVD.m) in relevance to the control OCVD. m affects the level of air pollution of urban landscapes by emissions of various enterprises. The relevance between these indicators is determined by a four-level scale elaborated specifically for the purpose. The method has been tested based on technogenic landscapes of Chernivtsi, Ukraine. The sensitivity of the suggested indicator for a wide range of pollutants has been proved and its ability to respond to different levels of greening of similar enterprises has been shown.
اظهر المزيد [+] اقل [-]Study on an Existing PV/Wind Hybrid System Using Biomass Gasifier for Energy Generation
2020
Malik, P. | Awasthi, M. | Sinha, S.
Untapped pine needles with high potential for energy generation in the hilly area are not only a waste of resource but also increase the chance of environmental hazards as forest fires and GHG emission. This study is conducted to propose a new hybrid system (PV/Wind/Biomass) using abundant pine needle resource as a replacement of existing roof-mounted PV/wind hybrid system and analyse the feasibility using Hybrid Optimization of Multiple Energy Resources (HOMER). Biomass gasifier is integrated to meet the increased load demand of 29.5 kW from 4.3 kW at the Centre for Energy and Environment Engineering building in NIT-Hamirpur. Both cases (with and without storage) has been considered in this research study. New optimized configuration is found to be a 1kWp PV array, one wind turbine of capacity 5kW, gasifier with a 17 kW capacity, 10 numbers of 12v batteries connected in series and 10 kW converter. The comparative analysis of off-grid hybrid systems shows that the system with the storage unit was more economical with 0.222 $/kWh as the cost of energy generation compared to the system without storage unit. The proposed hybrid system is found more reliable, economical and environment friendly and save about 27815 kg of CO2 per year when only diesel is used to meet the same energy demand. Therefore, biomass gasifier in decentralized small-scale power plants can be a better replacement for diesel generators.
اظهر المزيد [+] اقل [-]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.
اظهر المزيد [+] اقل [-]Artificial Neural Network Modeling for the Management of Oil Slick Transport in the Marine Environments
2020
Janati, M. | Kolahdoozan, M. | Imanian, H.
Due to an increase in demand of petroleum products which are transported by vessels or exported by pipelines, oil spill management becomes a controversial issue in coastal environment safety as well as making serious financial problems. After spilling oil in the water body, oil spreads as a thin layer on the water surface. Currents, waves and wind are the main causes of oil slick transport. These phenomena depend on the overall interaction among gravity, viscosity, surface tension and interfacial tension of oil in water bodies. In the current study, Artificial Neural Network (ANN) models have been designed and trained for the prediction of oil spreading and advection under different hydrodynamic conditions. In this regard, results obtained from a multiphase Lagrangian numerical model are deployed to train ANN model. The mentioned numerical model which is based on the moving particle semi-implicit (MPS) method is developed in the earlier stage of the study. In this research study, the MPS numerical model is first validated and verified against the analytical formulas which are based on experimental data cited in the literature. Then, various hydrodynamic conditions and oil spill scenarios were chosen to obtain different numerical model results. Finally, numerical model results are then deployed for training ANN model to provide a useful tool for urgent prediction of oil slick trajectory in order to manage the oil slick transport in the coastal environments.
اظهر المزيد [+] اقل [-]Estimation of Phosphorus Reduction from Wastewater by Artificial Neural Network, Random Forest and M5P Model Tree Approaches
2020
Kumar, S. | Deswal, S.
This study aims to examine the ability of free floating aquatic plants to remove phosphorus and to predict the reduction of phosphorus from rice mill wastewater using soft computing techniques. A mesocosm study was conducted at the mill premises under normal conditions, and reliable results were obtained. Four aquatic plants, namely water hyacinth, water lettuce, salvinia, and duckweed were used for this study. The growth of all the plants was inhibited in rice mill wastewater due to low pH, high chemical oxygen demand, high conductivity, and high phosphorus concentration. Subsequently, a 1:1 ratio of mill water to tap water was used. A control was maintained to assess the aquatic plant technology. In this study, the aquatic plants reduced the total phosphorus content up to 80 % within 15 days. A comparison between three modeling techniques e.g. Artificial neural network (ANN), Random forest (RF) and M5P has been done considering the reduction rate of total phosphorus as predicted variable. In this paper, the data set has been divided in two parts, 70 % is used to train the model and residual 30 % is used for testing of the model. Artificial neural network shows promising results as compared to random forest and M5P tree modelling. The root mean square error (RMSE) for all the three models is observed as 0.0162, 0.0204 and 0.0492 for ANN, RF and M5P tree, respectively.
اظهر المزيد [+] اقل [-]Phytotoxicity of Lead and Chromium on Germination, Seedling Establishment and Metal Uptake by Kenaf and Mesta
2020
Sultana, R. | Islam, S. M. N. | Zaman, M. W. | Uddin, N.
Heavy metal contaminated soil raises major global environmental and agricultural concern. Recently soil pollution through lead (Pb) and chromium (Cr) becoming serious problem and remediation or utilization of those contaminated soil with potential crops is of the outmost importance. The objectives of present study were to examine the effects of Pb and Cr on three different kenaf and mesta varieties for seed germination, seedling establishment and amount of Pb and Cr uptake by tested varieties in laboratory condition. Three varieties were used for the study namely, HC-95 (kenaf), CPL-72126 (mesta) and Samu-93 (mesta) and the treatments were combination of Pb and Cr chemical at (0,0), (60,60), (80,80), (100,100) and (120,120) mg/L. Increased level of lead and chromium gradually reduced the germination percentage and primary growth parameters compared to control. The shoot and root lengths were affected only little, whereas, the biomass showed a considerable reduction with the increase of Pb and Cr toxicity. Stress tolerance indices showed a gradual and negative response by the plant with the increase of metal concentrations. However, in all the levels of Pb and Cr treatment, the seedlings were capable to tolerate the toxicity and seedlings were established. Bioaccumulation of Cr was higher than that of Pb in all varieties and in all treatments. The interaction of Pb and Cr reduced the toxic effect of both metals to the plants. The findings are helpful for selecting fiber crop varieties for cultivation in contaminated soils or phytoremediation of Pb and Cr from the contaminated soils.
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