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Influence of In-Situ Scaling on Variability of Polluted Soil Erodibility Parameters Texto completo
2018
Al-Madhhachi, A. T. | Hasan, M. B.
Middle and southern Iraq suffers from polluted soils due to crude oil, spilled on land, leakage from transmitting pipe networks, or petroleum products from refineries. Many researchers have studied pollution impacts on the soil in details, but there is a clear lack of investigation on the influence of crude oil on soil erodibility. Recent researches have investigated the influence of pollution on erodibility parameters, which include critical shear stress (τc) and detachment factor (dc). The variability of dc and τc due to different in-situ scaling has not been thoroughly established for polluted and unpolluted soils. Thus this research aims at investigating the influence of different in-situ scaling ratios (1:1, 1:30, and 1:50) on variability of dc and τc for polluted and unpolluted soils under controlled laboratory conditions, using Jet Erosion Test (JET), and tries to compare the three solution techniques (namely, Blaisdell’s approach, depth scour approach, and iterative approach) to solve dc and τc from JETs for polluted and unpolluted soils. The polluted soil samples have been prepared by submerging the soil surface with crude oil for 24 hours prior to testing. Results show that there have been statistical differences in dc and τc between polluted and unpolluted soil samples on the dry side of water contents with no statistically significant difference of measured dc and τc being observed across different in-situ scale ratios for polluted and unpolluted soils. All told, the study shows less variability of measured dc and τc across different solution techniques, compared to previous study findings.
Mostrar más [+] Menos [-]Adsorption of Copper (II) Ions from Aqueous Solution onto Activated Carbon Prepared from Cane Papyrus Texto completo
2018
Alatabe, M. J.
The present study evaluates the suitability ofactivated carbon, prepared from Cane Papyrus, a plant that grows naturally and can be found quite easily, which serves as a biological sorbent for removal of Cu2+ ions from aqueous solutions. Fourier transform infra-red analysis for the activated carbon, prepared fromCane Papyrus confirms the presence of amino (–NH), carbonyl (–C=O), and hydroxyl (–OH) functional groups with Bath mode getting used to investigate the effects of the following parameters: adsorbent dosage (among the rates of 10, 20, and 30 g/L), pH values, Cu2+ initial concentration, and contact time. Results reveal higher efficiency (98%) of powdered adsorbent for removal of Cu2+ ions, which is found at pH=6 with 30 g/L activated carbon, prepared from Cane Papyrus, for a duration of 2 hours. The Freundlich isotherm model with linearized coefficient of 0.982 describes the adsorption process more suitably than the langmuir model, in which this rate equals to 0.899. Pseudo-second order kinetic equation best describes the kinetics of the reaction. Furthermore, it has been found that 0.5M HCl is a better desorbing agent than either 0.5 M NaOH or de-ionized water. The experimental data, obtained, demonstrate that the activated carbon prepared from Cane Papyrus can be used as a suitable adsorbent for Copper(II) ion removal from aqueous solutions.
Mostrar más [+] Menos [-]Industrial waste disposal alternatives in the process of aromatic compounds in petrochemical industry (case study: Nouri petrochemical complex, Asaluyeh, Iran Texto completo
2018
Heidari, L. | Jalili Ghazizade, M. | Salemi, A.
Application of aromatic compounds has dramatically increased as raw materials in various industries and different factories have been established to produce aromatic compounds. The current research aims at characterizing industrial waste generation in aromatics production process in petrochemical industries and determining the best feasible alternative for waste disposal. For this purpose, the world’s biggest aromatic producer, i.e. Nouri Petrochemical Complex (NPC), located in Asaluyeh, Iran, has been selected as case study. Firstly, different waste streams, generated during aromatics production, have been determined through a specific checklist. Spent industrial soil, catalyst, spent sieve, and Normal-Formyl-Morpholine (NFM) solvent are the most important identified wastes in NPC, with the former being the most generated waste in NPC with a rate of 600 tons per year. Afterwards, the mentioned waste has been sampled and important physicochemical specification such as heavy metals and organic compounds has been measured. Ni, Cu, and As are remarkable trace heavy metals, observed in all kinds of generated waste. In the next step, industrial waste classification and coding has been done, based on different guidelines. Finally different feasible alternatives like material recovery, sanitary landfill, and incineration have been compared, based on conventional economic, technical, and environmental indices. The best feasible waste disposal methods are the extraction of heavy metals from spent catalysts, recycling of spent molecular sieves and spent industrial soil as additives to building materials, and recovery of thermal energy by incineration of spent NFM solvent.
Mostrar más [+] Menos [-]Daytime Ozone Variation in Surface Air in a Subtropical Mangrove Estuary at Manakudy, South India Texto completo
2018
Krishna Sharma, R. | Chithambarathau, T | Elampari, K. | Nagaveena, S.
Surface ozone (SOZ) can be very harmful if it exceeds the threshold limit. It can accumulate over sea and can return back to the land along with the breeze. Rural and vegetation rich areas often record elevated levels of surface ozone because of the variations in Volatile Organic Compound (VOC) levels, wind velocity and direction. Similarly methane is also an important greenhouse gas and plays a vital role in the atmospheric budget. In this work, ozone and methane levels measured during daytime in a mangrove estuary near Manakudy(8.0911 N, 77.477 E),kanyakumari, South India for a period of ten months from March 2014 to December 2014 are analyzed.SOZ showed an imprecise diurnal pattern with an early morning peak whereas methane recorded an apparent diurnality. The maximum value of SOZ was around 50 ppb. Summer months recorded high levels of SOZ followed by Southwest monsoon (SWM) and Northeast monsoon (NEM).High levels of methane were found in SWM followed by NEM and low concentration during summer. The correlation between SOZ and methane was found as r = -0.257, p
Mostrar más [+] Menos [-]Anthropogenic share of metal contents in soils of urban areas Texto completo
2018
Fazeli, G. | Karbassi, A.R. | khoramnejadian, Sh. | Nasrabadi, T.
In the present investigation, 41 soil samples were subjected to single step chemical partitioning to assess the lithogenic and non-lithogenic portions of metals in Tehran's soils. The share of various studied metals in the anthropogenic portion ranges from as low as 0.2% to as high as 85% of bulk concentration. Geo-accumulation index (Igeo) showed that Cd falls within "heavily contaminated" soils. It might be inferred that Ni, Cu, Cr, Zn, Co and Ca fall within "Deficient to minimal" class in accordance with enrichment factor (EF) classification.. Enrichment factor values (to some extents) match with the chemical partition studies results (except for Ni and Cr). The very low Ca content of soil samples could be indicative of low biological productivity in the Tehran's soil. Also the very low concentrations of Mn could be indicative of reducing environment in soils of Tehran.
Mostrar más [+] Menos [-]Two-dimensional advection-dispersion equation with depth- dependent variable source concentration Texto completo
2018
Chatterjee, Ayan | Singh, Mritunjay
The present work solves two-dimensional Advection-Dispersion Equation (ADE) in a semi-infinite domain. A variable source concentration is regarded as the monotonic decreasing function at the source boundary (x=0). Depth-dependent variables are considered to incorporate real life situations in this modeling study, with zero flux condition assumed to occur at the exit boundary of the domain, i.e. its semi-infinite part. Without losing any generality, one can consider that the aquifer is initially contamination-free. Thus, the current study explores variations of two-dimensional contaminant concentration with depth throughout the domain, showing them graphically. Non-point source problem, i.e. the line source problem, can be discussed by solving two-dimensional depth-dependent variable source problem, as x=0 is a 2D line. A new transformation has been used to transform the time-dependent ADE to one with constant coefficients, with Matlab (pdetool) being employed in order to solve the problem, numerically, using finite element method.
Mostrar más [+] Menos [-]Influence of atmospheric circulation patterns on dust transport during Harmattan Period in West Africa Texto completo
2018
Oluleye, Ayodeji | Jimoh, Olatunji
This study has used TOMS AI as well as the reanalysis dataset of thirty-four years (1979-2012) to investigate the influence of atmospheric circulation on dust transport during the Harmattan period in West Africa, using Aerosol Index (AI) data, obtained from various satellite sensors. Changes in Inter-Tropical Discontinuity (ITD), Sea Surface Temperature (SST) over the Gulf of Guinea, and North Atlantic Oscillation (NAO) during Harmattan period (November-March) have been analyzed on daily basis with Harmattan dust mobilization as well as atmospheric circulation pattern being evaluated via a kernel density estimate that shows the relation between the two variables. The study has found out that strong north-easterly (NE) trade winds were over most of the Sahelian region of West Africa during the winter months with the maximum wind speed reaching 8.61 m/s in January. The strength of NE winds determines the extent of dust transport to the coast of Gulf of Guinea during winter. This study has also confirmed that the occurrence of the Harmattan chiefly depends on SST in Atlantic Ocean as well as ITD position, not to mention the strength of low level winds. However, it has been noted that NAO has limited effects on dust mobilization in West Africa, in shear contrast to North Africa where NAO is a strong factor in dust mobilization.
Mostrar más [+] Menos [-]Wastewater Treatment by Azolla Filiculoides: A Study on Color, Odor, COD, Nitrate, and Phosphate Removal Texto completo
2018
Golzary, Abooali | Tavakoli, Omid | Rezaei, Yasemin | Karbassi, Abdolreza
The aquatic fern Azolla, a small-leaf floating plant that lives in symbiosis with a nitrogen fixing cyanobacteria (Anabaena), is an outstanding plant, thanks to its high biomass productivity along with its tremendous rate per unit area for nitrogen-fixation. The present study investigates the potential growth of Azolla in secondary effluents for removal of COD, phosphorus, and nitrogen. Results have shown that N and P removal at 100 ppm of each component in separate medium turned out to be 36% and 44%, respectively, whereas in case of a mixed solution of these two compounds, N and P removal declined to 33% and 40.5%, respectively. Moreover, results have suggested that in the presence of phosphorus nitrogen absorption decreased. Furthermore, Azolla has revealed a high potential of COD removal by 98.8% in 28 days. Finally, Azolla may be one of the most promising agents to remove COD and treat nitrogen-free and phosphorus-rich wastewaters.
Mostrar más [+] Menos [-]Physico-Chemical and Genotoxicity Assessments of Palm Oil Mill Effluent Generated by a Corporate Refinery In Nigeria Texto completo
2018
Dada, Ebenezer | Akinola, Modupe | Haruna, Rekiyat
The rising global demand for palm oil and its associated products has led to increased numbers of palm oil refineries with its attendant effluent discharge. Many researches have confirmed the ecological disruptive potentiality of Palm Oil Mill Effluent (POME), still further attention has to be directed at POME’s potential genotoxicity. The present study has made physico-chemical and genotoxicity assessments of POME from a corporate refinery in Nigeria, using the American Public Health Association (APHA) procedures along with Allium cepa root assay. Allium cepa roots were grown in graduated concentrations of POME and the roots were analyzed for chromosomal aberrations. Results suggest that POME caused growth inhibitions and chromosomal aberrations in A. cepa roots. with mitotic index of A. cepa roots dropping as POME concentrations were increased. The chromosomal aberrations induced in A. cepa were vagrant, sticky chromosomes, bi-nucleated cells, and C-mitosis. These results indicate that palm oil mill effluent is not only capable of causing ecological disruptions in the receiving environment, but is also potentially genotoxic to resident organisms. It is recommended that if effluents from palm oil mill refineries cannot be converted to other useful products and ought to be disposed of, it should first be properly treated and tested for genotoxicity.
Mostrar más [+] Menos [-]A Novel Open Raceway Pond Design for Microalgae Growth and Nutrients Removal from Treated Slaughterhouse Wastewater Texto completo
2018
Habibi, Adnan | Teymouri, Abolghasem | Delavari Amrei, Hossein | Pajoum shariati, Farshid
The present work investigates nitrate and phosphate removal from synthetic treated slaughterhouse wastewater in a novel open raceway pond with sedimentation zone. For this purpose, microalgae Chlorella salina has been cultivated in synthetic wastewater and sedimentation zone has been added to enhance both algae separation in the system and nutrient removal. The effectiveness of Chlorella salina to treat nitrate and phosphate has been tested in open raceway ponds with harvest system. It has been found that Biomass concentration of the Chlorella salina is 1.35 g/L during 11 days of experiment. Also, maximum specific growth rate of the species in the pond has been 0.74 day-1. Throughout the cultivation period, nitrate and phosphate have been analyzed to show that their average removal efficiencies were 100% and 45%, respectively. It can be concluded that the growth of Chlorella salina in novel open pond system is an effective way to reduce nitrate and phosphate levels in slaughterhouse synthetic wastewater. Also, wastewater is suitable for algal growth.
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