Search results for: alkaline earth metals

Authors: Ahmed Ferhati, Arezki Adjrad, Ratiba Mitiche-Kettab, Hakim Djafer Khodja

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The porous media are omnipresent around us that they are natural as sand, clay, rocks, or manufactured like concretes, cement, and ceramics. The variety of porous environment indicates a wide material range which can be very different from each other. Their common point is to be made up of a solid matrix and a porous space. In our case of study, we made the modeling of the flows in porous environments through the massives as in the case of an earth dam. The computer code used (PLAXIS) offer the possibility of modeling of various structures, in particular, the works in lands because that it deals with the pore water pressure due to the underground flow and the calculation of the plastic deformations. To confirm results obtained by PLAXIS, GeoStudio SEEP/W code was used. This work treats modeling of flows and mechanical and hydraulic behavior of earth dam. A general framework which can fit the calculation of this kind of structures and the coupling of the soil consolidation and free surface flows was defined. In this study; we have confronted a real case modeling of an earth dam. It was shown, in particular, that it is possible to entirely lead the calculation of real dam and to get encouraging results from the hydraulic and mechanical point of view.

Keywords: analyzes, dam, flow, modeling, PLAXIS, seep/w, slope

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Authors: Marc Evenst Jn Jacques, Sophie Bernard

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Electrical and electronic applications, as well as rechargeable batteries, are common in any economy. They also contain a number of important and valuable metals. It is critical to investigate the impact of these new materials or volume sources on the metal market dynamics. This paper investigates the impact of responsible recycling within the European region on metal price volatility. As far as we know, no empirical studies have been conducted to assess the role of metal recycling in metal market price volatility. The goal of this paper is to test the claim that metal recycling helps to cushion price volatility. A set of circular economy indicators/variables, namely, 1) annual total trade values of recycled metals, 2) annual volume of scrap traded and 3) circular material use rate, and 4) information about recycling, are used to estimate the volatility of monthly spot prices of regular metals. A combination of the GARCH-MIDAS model for mixed frequency data sampling and a simple GARCH (1,1) model for the same frequency variables was adopted to examine the potential links between each variable and price volatility. We discovered that from 2010 to 2019, except for Nickel, scrap consumption (Millions of tons), Scrap Trade Values, and Recycled Material use rate had no significant impact on the price volatility of standard metals (Aluminum, Lead) and precious metals (Gold and Platinum). Worldwide interest in recycling has no impact on returns or volatility. Specific interest in metal recycling did have a link to the mean return equation for Aluminum, Gold and to the volatility equation for lead and Nickel.

Keywords: recycling, circular economy, price volatility, GARCH, mixed data sampling

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Authors: Saman Hajmohamadi, Sohrab Hajmohamadi

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The objectives of this experiment were to investigate the application of new ligands including different atoms and evaluation of their nucleophile effects against various metals. Chemistry researchers are really interested in this field. From among various ligands, there are some ligands with different coordinating ligands as well. There are great number of intermediate complexes and major elements of organic compositions with various atoms. There is a regular adding of new compositions. Complexes are the most important chemical combinations with various catalysts and biological, medicinal and other applications. Those complexes with ligands including different atom givers are really important and their synthesis could solve most of chemical problems. Supplying of new ligands is an important and key part of coordination chemistry which may cause some varieties and different properties in complexes with equal central nucleus. As a result, this research has evaluated new ligands including different coordination atoms, such as oxygen, nitrogen etc. along with their behavior against various metals like copper, nickel, iron etc.

Keywords: ligands, nucleophile, iron, cobalt, copper

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Authors: Violina R. Angelova, Mariana N. Perifanova-Nemska, Galina P. Uzunova, Krasimir I. Ivanov, Huu Q. Lee

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A field study was conducted to evaluate the efficacy of the sunflower (Helianthus annuus L.) for phytoremediation of contaminated soils. The experiment was performed on an agricultural field contaminated by the Non-Ferrous-Metal Works near Plovdiv, Bulgaria. Field experiments with a randomized, complete block design with five treatments (control, compost amendments added at 20 and 40 t/daa, and vemicompost amendments added at 20 and 40 t/daa) were carried out. The accumulation of heavy metals in the sunflower plant and the quality of the sunflower oil (heavy metals and fatty acid composition) were determined. The tested organic amendments significantly influenced the uptake of Pb, Zn and Cd by the sunflower plant. The incorporation of 40 t/decare of compost and 20 t/decare of vermicompost to the soil led to an increase in the ability of the sunflower to take up and accumulate Cd, Pb and Zn. Sunflower can be subjected to the accumulators of Pb, Zn and Cd and can be successfully used for phytoremediation of contaminated soils with heavy metals. The 40 t/daa compost treatment led to a decrease in heavy metal content in sunflower oil to below the regulated limits. Oil content and fatty acids composition were affected by compost and vermicompost amendment treatments. Adding compost and vermicompost increased the oil content in the seeds. Adding organic amendments increased the content of stearic, palmitoleic and oleic acids, and reduced the content of palmitic and gadoleic acids in sunflower oil. The possibility of further industrial processing of seeds to oil and use of the obtained oil will make sunflowers economically interesting crops for farmers of phytoremediation technology.

Keywords: heavy metals, phytoremediation, polluted soils, sunflower

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Authors: Oluwaseun A. Oyetade, Roelof J. Kriek

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The development of effective catalysts for the oxygen evolution reaction (OER) is of great importance to combat energy-related concerns in the environment. Herein, we report a one-step solvothermal method employed for the fabrication of nickel selenide hybrids (NiSe-Ni₃Se₂) and a series of nickel selenide hybrid/multiwalled carbon nanotube composites (NiSe-Ni₃Se₂/MWCNT) as electrocatalysts for OER in alkaline media. The catalytic activities of these catalysts were investigated via several electrochemical characterization techniques, such as linear sweep voltammetry, chronoamperometric studies at constant potential, electrochemical surface area determination, and Tafel slope calculation, under alkaline conditions. Morphological observations demonstrated the agglomeration of non-uniform NiSe-Ni₃Se₂ microspheres around carbon nanotubes (CNTs), demonstrating the successful synthesis of NiSe-Ni₃Se₂/MWCNT nanocomposites. Among the tested electrocatalysts, the 20% NiSe-Ni₃Se₂/MWCNT nanocomposite demonstrated the highest activity, exhibiting an overpotential of 325 mV to achieve a current density of 10 mA.cm⁻² in 0.1 mol.dm⁻³ KOH solution. The NiSe-Ni₃Se₂/MWCNT nanocomposites showed improved activity toward OER compared to bare NiSe-Ni₃Se₂ hybrids and MWCNTs, exhibiting an overpotential of 528, 392 and 434 mV for 10%, 30% and 50% NiSe-Ni₃Se₂/MWCNT nanocomposites, respectively. These results compare favourably to the overpotential of noble catalysts, such as RuO₂ and IrO₂. Our results imply that the addition of MWCNTs increased the activity of NiSe-Ni₃Se₂ hybrids due to an increased number of catalytic sites, dispersion of NiSe-Ni₃Se₂ hybrid nanoparticles, and electronic conductivity of the nanocomposites. These nanocomposites also demonstrated better long-term stability compared to NiSe-Ni₃Se₂ hybrids and MWCNTs. Hence, NiSe-Ni₃Se₂/MWCNT nanocomposites possess the potential as effective electrocatalysts for OER in alkaline media.

Keywords: carbon nanotubes, electrocatalysts, nanocomposites, nickel selenide hybrids, oxygen evolution reaction

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Authors: Dessie Tibebe, Muluken Asmare, Marye Mulugeta, Yezbie Kassa, Zerubabel Moges, Dereje Yenealem, Tarekegn Fentie, Agmas Amare

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The performance of electrocoagulation (EC) using Aluminium electrodes for the treatment of effluent-containing chromium metal using a fixed bed electrochemical batch reactor was studied. In the present work, the efficiency evaluation of EC in removing physicochemical and heavy metals from real industrial tannery wastewater in the Amhara region, collected from Bahirdar, Debre Brihan, and Haik, was investigated. The treated and untreated samples were determined by AAS and ICP OES spectrophotometers. The results indicated that selected heavy metals were removed in all experiments with high removal percentages. The optimal results were obtained regarding both cost and electrocoagulation efficiency with initial pH = 3, initial concentration = 40 mg/L, electrolysis time = 30 min, current density = 40 mA/cm2, and temperature = 25oC favored metal removal. The maximum removal percentages of selected metals obtained were 84.42% for Haik, 92.64% for Bahir Dar and 94.90% for Debre Brihan. The sacrificial electrode and sludge were characterized by FT-IR, SEM and XRD. After treatment, some metals like chromium will be used again as a tanning agent in leather processing to promote a circular economy.

Keywords: electrochemical, treatment, aluminum, tannery effluent

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Authors: Islam Zeb

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The water of poor quality used for irrigation purposes has the potential to be the direct source of contamination and a vehicle for spreading contamination in the field. A number of wide-ranging review articles have been published that highlight irrigation water as a source of heavy metals toxicity which leads to chronic diseases in the human body. Here a study was planned to determine the microbial and heavy metals status of irrigation water collected from various locations of district Swat in various months. The analyses were carried out at the Environmental Horticulture Laboratory, Department of Horticulture, The University of Agriculture Peshawar, during the year 2018 – 19. The experiment was laid out in Randomized Complete Block Design (RCBD) with two factors and three replicates. Factor A consist of different locations and factor B represent various months. The result of heavy metals concentration in different regions, maximum Lead, Cadmium, Chromium, Nickel and Copper (4.27, 0.56, 0.81, 1.33 and 1.51 mg L-1 respectively) were noted for the irrigation water samples collected from Mingora while minimum Lead, Cadmium, Chromium, Nickel and Copper concentration (2.59, 0.30, 0.27, 0.40 and 0.54 mg L-1 respectively) were noted for the samples of matta. Whereas results of heavy metals content in irrigation water samples for various months maximum content of Lead, Cadmium, Chromium, Nickel and Copper (4.56, 0.63, 1.15, 1.31 and 1.48 mg L-1 respectively) were noted for the samples collected in Jan/Feb while lowest values for Lead, Cadmium, Chromium, Nickel and Copper (2.38, 0.24, 0.21, 0.41 and 0.52 mg L-1 respectively) were noted in the samples of July/August. A significant interaction was found for all the studied parameters. It was concluded that the concentration of heavy metal was maximum in irrigation water samples collected from the Mingora location during the month of Jan/Feb because Mingora is the most polluted area as compared to other studied regions, whereas the water content in winter goes to freeze and mostly contaminated water is used for irrigation purposes.

Keywords: irrigation water, various months, different regions, heavy metals contamination, Swat

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Authors: Jiancheng Zheng

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When metals are released into water from mining activities, they undergo changes chemically, physically and biologically and then may become more mobile and transportable along the waterway from their original sites. Natural colloids, including both organic and inorganic entities, are naturally occurring in any aquatic environment with sizes in the nanometer range. Natural colloids in a water system play an important role, quite often a key role, in binding and transporting compounds. When assessing and evaluating metals in natural waters, their sources, mobility, fate, and distribution patterns in the system are the major concerns from the point of view of assessing environmental contamination and pollution during resource development. There are a few ways to quantify colloids and accordingly study how metals distribute on different sizes of colloids. Current research results show that the presence of colloids can enhance the transport of some heavy metals in water, while heavy metals may also have an influence on the transport of colloids when cations in the water system change colloids and/or the ion strength of the water system changes. Therefore, studies into the relationship between different sizes of colloids and different metals in a water system are necessary and needed as natural colloids in water systems are complex mixtures of both organic and inorganic as well as biological materials. Their stability could be sensitive to changes in their shapes, phases, hardness and functionalities due to coagulation and deposition et al. and chemical, physical, and biological reactions. Because metal contaminants’ adsorption on surfaces of colloids is closely related to colloid properties, it is desired to fraction water samples as soon as possible after a sample is taken in the natural environment in order to avoid changes to water samples during transportation and storage. For this reason, this study carried out groundwater sample processing in the field, using Prep/Scale tangential flow filtration systems with 3-level cartridges (1 kDa, 10 kDa and 100 kDa). Groundwater samples from seven sites at Fort MacMurray, Alberta, Canada, were fractionated during the 2015 field sampling season. All samples were processed within 3 hours after samples were taken. Preliminary results show that although the distribution pattern of metals on colloids may vary with different samples taken from different sites, some elements often tend to larger colloids (such as Fe and Re), some to finer colloids (such as Sb and Zn), while some of them mainly in the dissolved form (such as Mo and Be). This information is useful to evaluate and project the fate and mobility of different metals in the groundwaters and possibly in environmental water systems.

Keywords: metal, colloid, groundwater, mobility, fractionation, sorption

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Authors: Khanom Simarani

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Rice husk has been widely reported as a good sorbent for heavy metals. Pre treatment of rice husk minimizes cellulose crystallinity and increases the surface area thus ensuring better adsorption capacity. Commercial base and natural base-treated rice husk were used to investigate the potential of Ni(II) adsorption from synthetic solutions and waste water in batch systems. Effects of process variables such as pH, contact time, adsorbent dose, initial Ni (II) concentration were studied. Optimum Ni (II) adsorption was observed at pH 6 within 60 min of contact time. Experimental data showed increased amount of adsorbed Ni(II) with increasing adsorbent dose and decreased percent of adsorption with increasing initial Ni(II) concentration. Kinetic isotherms (Langmuir, Freundlich) were also applied. Biosorption mechanism of rice husk was analyzed using SEM/EDS, FT-IR, and XRD. The results revealed that natural base produced from agroindustrial waste could be used as efficient as commercial bases during pre treatment rice husk in removing Ni(II) from waste waters within 15 min.

Keywords: Nickel removal, adsorbent, heavy metal, biomass

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Authors: Hafizan Junoh, Kumaran Palanisamy, Yip Chan Heng, Pua Fei Ling

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This study investigates the influence of low temperature thermo-chemical pretreatment of organic food waste on the performance of COD solubilisation. Both temperature and alkaline agent were reported to have an effect on solubilizing any possible biomass including organic food waste. The three independent variables considered in this pretreatment were temperature (50-90oC), pretreatment time (30-120 minutes) and alkaline concentration, sodium hydroxide, NaOH (0.7-15 g/L). The optimal condition obtained were 90oC, 15 g/L NaOH for 2 hours. Solubilisation has potential in enhancing methane production by providing a high amount of soluble components at an early stage during anaerobic digestion.

Keywords: food waste, pretreatments, respond surface methodology, ANOVA, anaerobic digestion

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Authors: Debesh R. Roy

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The fundamental issue in understanding the origin and growth mechanism of nanomaterials, from a fundamental unit is a big challenging problem to the scientists. Recently, an immense attention is generated to the researchers for prediction of exceptionally stable atomic cluster units as the building units for future smart materials. The present study is a systematic investigation on the stability and electronic properties of a series of bimetallic (semiconductor-alkaline earth) clusters, viz., BxMg3 (x=1-5) is performed, in search for exceptional and/ or unusual stable motifs. A very popular hybrid exchange-correlation functional, B3LYP as proposed by A. D. Becke along with a higher basis set, viz., 6-31+G[d,p] is employed for this purpose under the density functional formalism. The magic stability among the concerned clusters is explained using the jellium model. It is evident from the present study that the magic stability of B4Mg3 cluster arises due to the jellium shell closure.

Keywords: atomic clusters, density functional theory, jellium model, magic clusters, smart nanomaterials

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Authors: Wafeek Mohamed Ibrahim Mohamed

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In the era of globalization and openness informational. Anyone who thinks about innovation in the earth population in Islam in our contemporary reality, he will find that it is not destined to its civilized extension to last. The purpose of the research is a trial to reach a realistic vision for creative, innovative and intellectual thought for the earth population in Islam as an instrument to Confrontation and observe the changes that have affected in the architecture of the land during different eras. Through knowing the controls of the ruling legitimacy(that served as definitions and laws which formulate its features) and using customs, traditions, and conventions as a telescope for the earth population in Islam, It explained the impact of them on features of creative formation for the architecture of the land in our contemporary reality. The study shows a modern vision to identify innovation in the earth population in Islam. As well as reformulating its mental image and monitoring its changes in Islamic heritage cities. This will be done through a two main branches: firstly, set forth a theory represented in studying creative concepts which formulate the population of the earth in Islam. Such as initiative and responsibility for reviving the dead land, the lane [alley] as formation unit and social solidarity,… Etc.. The second branch is preparing a practical, critical vision for innovative conceptual thought for the architecture of the land of Islam, through studying the development of a traditional Islamic city., The conceptual thought of making the birth festival ["Al-Refaee"] and its emulation for governing roles in the traditional city building. The research concludes The necessity of forming the suggested a creative vision for identifying how to re-form the conceptual for our contemporary population of the earth. It poses an important question which is how to return to creativity in the architecture of the land of Islam in our built environments.

Keywords: innovation and creation, architecture, the land in Islam, criticism of design

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Authors: Shumaila Shakoor

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The levels of metal pollution (Pb, Cd, Cu, Zn) were investigated in the leaves of Dalbergia sisso in urban areas of the Sahiwal and Faisalabad City. For this purpose, three habitats were selected for sampling (roads, residential areas and parks). High concentration of metal was found in roadside samples as compared to residential areas and parks. In Sahiwal city the mean concentration of Copper (7.68µgg-¹) Zinc (43.55µgg-¹) and lead (4.79µgg-¹) were detected. Similarly, concentration of Cu, Zn, Pb and Cd in leaves of Faisalabad city ranged from 14.4-11.3µgg-¹, 49.7-49.5µgg-¹,138.7-47.1µgg-¹. Highest concentration of heavy metals was detected in Faisalabad as compared to Sahiwal city and level of heavy metals was below the threshold limits, therefore, the concentration of heavy metals was not high in Dalbergia sissoo.

Keywords: cadmium, copper, lead, zinc

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Authors: I. M. Sakr, Ali M. Abdelsalam, K. A. Ibrahim, W. A. El-Askary

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This paper presents an experimental study for hydrogen production using alkaline water electrolysis operated by solar energy. Two methods are used and compared for separation between the cathode and anode, which are acrylic separator and polymeric membrane. Further, the effects of electrolyte concentration, solar insolation, and space between the pair of electrodes on the amount of hydrogen produced and consequently on the overall electrolysis efficiency are investigated. It is found that the rate of hydrogen production increases using the polymeric membrane installed between the electrodes. The experimental results show also that, the performance of alkaline water electrolysis unit is dominated by the electrolyte concentration and the gap between the electrodes. Smaller gaps between the pair of electrodes are demonstrated to produce higher rates of hydrogen with higher system efficiency.

Keywords: hydrogen production, water electrolysis, solar energy, concentration

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Authors: Aicha Assal, El Mostapha Lotfi

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Rapid industrialization and population growth are currently the main causes of energy and environmental problems associated with wastewater treatment. Wastewater treatment plants (WWTPs) aim to treat wastewater before discharging it into the environment, but they are not yet capable of treating non-biodegradable contaminants such as heavy metals. Toxic heavy metals can disrupt biological processes in WWTPs. Consequently, it is crucial to combine additional physico-chemical treatments with WWTPs to ensure effective wastewater treatment. In this study, the authors examined the pretreatment process for urban wastewater generated by the El Jadida WWTP in order to assess its treatment efficiency. Various physicochemical and spatiotemporal parameters of the WWTP's raw and treated water were studied, including temperature, pH, conductivity, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), suspended solids (SS), total nitrogen, and total phosphorus. The results showed an improvement in treatment yields, with measured performance values of 77% for BOD5, 63% for COD, and 66% for TSS. However, spectroscopic analyses revealed persistent coloration in wastewater samples leaving the WWTP, as well as the presence of heavy metals such as Zn, cadmium, chromium, and cobalt, detected by inductively coupled plasma optical emission spectroscopy (ICP-OES). To remedy these staining problems and reduce the presence of heavy metals, a new low-cost, environmentally-friendly eggshell-based solution was proposed. This method eliminated most heavy metals such as cobalt, beryllium, silver, and copper and significantly reduced the amount of cadmium, lead, chromium, manganese, aluminium, and Zn. In addition, the bioadsorbent was able to decolorize wastewater by up to 84%. This adsorption process is, therefore, of great interest for ensuring the quality of wastewater and promoting its reuse in irrigation.

Keywords: WWTP, wastewater, heavy metals, decoloration, depollution, COD, BOD5

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Authors: Nice Vasconcelos Coimbra, Fábio dos Santos Gonçalves, Marisa Nascimento, Ellen Cristine Giese

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The development of chemical routes for the recovery and separation of rare earth elements (REE) is seen as a priority and strategic action by several countries demanding these elements. Among the possibilities of alternative routes, the biosorption process has been evaluated in our laboratory. In this theme, the present work attempts to assess and fit the solution equilibrium data in Langmuir, Freundlich and DKR isothermal models, based on the biosorption results of the lanthanum and samarium elements by Bacillus subtilis immobilized on calcium alginate gel. It was observed that the preference of adsorption of REE by the immobilized biomass followed the order Sm (III)> La (III). It can be concluded that among the studied isotherms models, the Langmuir model presented better mathematical results than the Freundlich and DKR models.

Keywords: rare earth elements, biosorption, Bacillus subtilis, adsorption isotherm models

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Authors: Ahmed M. Haddad, Hadeel S. El-Shaal, Gadallah M. Abu-Elreesh

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Some of filamentous fungi can be used for biodiesel production as they are able to accumulate high amounts of intracellular lipids when grown at stress conditions. Aspergillus fumigatus sp. was isolated from Nile delta soil in Egypt. The fungus was primarily screened for its capacity to accumulate lipids using Nile red staining assay. The fungus could accumulate more than 20% of its biomass as lipids when grown at optimized minimal medium. After lipid extraction, we could use fungal cell debris to remove some heavy metals from contaminated waste water. The fungal cell debris could remove Cd, Cr, and Zn with absorption efficiency of 73%, 83.43%, and 69.39% respectively. In conclusion, the Aspergillus fumigatus isolate may be considered as a promising biodiesel producer, and its biomass waste can be further used for bioremediation of wastewater contaminated with heavy metals.

Keywords: biodiesel, bioremediation, fungi, heavy metals, lipids, oleaginous

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Authors: Walter W. Loo

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China declared the “zero discharge rules which leave no toxics into our living environment and deliver blue sky, green land and clean water to many generations to come”. The achievement of ZWD will provide conservation of water, soil and energy and provide drastic increase in Gross Domestic Products (GDP). Our society’s engine needs a major tune up; it is sputtering. ZWD is achieved in world’s space stations – no toxic air emission and the water is totally recycled and solid wastes all come back to earth. This is all done with solar power. These are all achieved under extreme temperature, pressure and zero gravity in space. ZWD can be achieved on earth under much less fluctuations in temperature, pressure and normal gravity environment. ZWD systems are not expensive and will have multiple beneficial returns on investment which are both financially and environmentally acceptable. The paper will include successful case histories since the mid-1970s. ZWD discharge can be applied to the following types of projects: nuclear and coal fire power plants with a closed loop system that will eliminate thermal water discharge; residential communities with wastewater treatment sump and recycle the water use as a secondary water supply; waste water treatment Plants with complete water recycling including water distillation to produce distilled water by very economical 24-hours solar power plant. Landfill remediation is based on neutralization of landfilled gas odor and preventing anaerobic leachate formation. It is an aerobic condition which will render landfill gas emission explosion proof. Desert development is the development of recovering soil moisture from soil and completing a closed loop water cycle by solar energy within and underneath an enclosed greenhouse. Salt-alkali land development can be achieved by solar distillation of salty shallow water into distilled water. The distilled water can be used for soil washing and irrigation and complete a closed loop water cycle with energy and water conservation. Heavy metals remediation can be achieved by precipitation of dissolved toxic metals below the plant or vegetation root zone by solar electricity without pumping and treating. Soil and groundwater remediation - abandoned refineries, chemical and pesticide factories can be remediated by in-situ electrobiochemical and bioventing treatment method without pumping or excavation. Toxic organic chemicals are oxidized into carbon dioxide and heavy metals precipitated below plant and vegetation root zone. New water sources: low temperature distilled water can be recycled for repeated use within a greenhouse environment by solar distillation; nano bubble water can be made from the distilled water with nano bubbles of oxygen, nitrogen and carbon dioxide from air (fertilizer water) and also eliminate the use of pesticides because the nano oxygen will break the insect growth chain in the larvae state. Three dimensional high yield greenhouses can be constructed by complete water recycling using the vadose zone soil as a filter with no farming wastewater discharge.

Keywords: greenhouses, no discharge, remediation of soil and water, wastewater

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Authors: Elsayed A. M. Shokr, A. Alhazemi, T. Naser, Talal A. Zuhair, Adel A. Zuhair, Ahmed N. Alshamary, Thamer A. Alanazi, Hosam A. Alanazi

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The main threats to human health from heavy metals are associated with exposure to Pb, Cd, Cu, Mo, Zn, Ni, Mn Co and Cr. is mainly via intake of drinking water being the most important source in most populations. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years. Although several adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues, and is even increasing in some parts of the world, in particular in less developed countries, though emissions have declined in most developed countries over the last 100 years. A strong relationship between contaminated drinking water with heavy metals from some of the stations of water shopping in Hail, KSA and chronic diseases such as renal failure, liver cirrhosis, and chronic anemia has been identified in this study. These diseases are apparently related to contaminant drinking water with heavy metals such as Pb, Cd, Cu, Mo, Zn, Ni, Mn Co and Cr. Renal failure is related to contaminate drinking water with lead and cadmium, liver cirrhosis to copper and molybdenum, and chronic anemia to copper and cadmium. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage but possibly also bone effects and fractures. The general population is primarily exposed to mercury via drinking water being a major source of methyl mercury exposure, and dental amalgam. During the last century lead, cadmium, zinc, iron and arsenic is mainly via intake of drinking water being the most important source in most populations. Long-term exposure to lead, cadmium, zinc, iron and arsenic in drinking-water is mainly related to primarily in the form of kidney damage. Studies of these diseases suggest that abnormal incidence in specific areas is related to toxic materials in the groundwater and thereby led to the contamination of drinking water in these areas.

Keywords: heavy metals, liver functions, kidney functions and chronic renal failure, hail, renal, water

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Authors: Muhammad Mohsin, Mir Md Abdus Salam, Pertti Pulkkinen, Ari Pappinen

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Soil and water contamination by heavy metals is a major challenging issue for the environment. Phytoextraction is an emerging, environmentally friendly and cost-efficient technology in which plants are used to eliminate pollutants from the soil and water. We aimed to assess the copper (Cu) and zinc (Zn) removal efficiency by two willow varieties such as Klara (S. viminalis x S. schwerinii x S. dasyclados) and Karin ((S.schwerinii x S. viminalis) x (S. viminalis x S.burjatica)) under different soil treatments (control/unpolluted, polluted, lime with polluted, wood ash with polluted). In 180 days of pot experiment, these willow varieties were grown in a highly polluted soil collected from Pyhasalmi mining area in Finland. The lime and wood ash were added to the polluted soil to improve the soil pH and observe their effects on metals accumulation in plant biomass. The Inductively Coupled Plasma Optical Emission Spectrometer (ELAN 6000 ICP-EOS, Perkin-Elmer Corporation) was used in this study to assess the heavy metals concentration in the plant biomass. The result shows that both varieties of willow have the capability to accumulate the considerable amount of Cu and Zn varying from 36.95 to 314.80 mg kg⁻¹ and 260.66 to 858.70 mg kg⁻¹, respectively. The application of lime and wood ash substantially affected the stimulation of the plant height, dry biomass and deposition of Cu and Zn into total plant biomass. Besides, the lime application appeared to upsurge Cu and Zn concentrations in the shoots and leaves in both willow varieties when planted in polluted soil. However, wood ash application was found more efficient to mobilize the metals in the roots of both varieties. The study recommends willow plantations to rehabilitate the Cu and Zn polluted soils.

Keywords: heavy metals, lime, phytoextraction, wood ash, willow

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Authors: M. Diafi, M. Omari, B. Gasmi

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Perovskite-type La1−xCaxAlO3 were synthesized at 1000◦C by a co- precipitation method. The synthesized oxide powders were characterized by X-ray diffraction (XRD) and the oxide powders were produced in the form of films on pretreated Ni-supports by an oxide-slurry painting technique their electrocatalytic activities towards methanol oxidation in alkaline solutions at 25°C using cyclic voltammetry, chronoamperometry, and anodic Tafel polarization techniques. The oxide catalysts followed the rhombohedral hexagonal crystal geometry. The rate of electro-oxidation of methanol was found to increase with increasing substitution of La by Ca in the oxide matrix. The reaction indicated a Tafel slope of ~2.303RT/F, The electrochemical apparent activation energy (〖∆H〗_el^(°#)) was observed to decrease on increasing Ca content. The results point out the optimum electrode activity and stability of the Ca is x=0.6 of composition.

Keywords: electrocatalysis, oxygen evolution, perovskite-type La1−x Cax AlO3, methanol oxidation

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Authors: M. Budakoglu, M. Karaman, D. Kiran, Z. Doner, B. Zeytuncu, B. Tanç, M. Kumral

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Lake Acıgöl is one of the large saline lacustrine environment in Turkey. Eleven trace metals (Cr, Mn, Fe, Al, Co, Ni, Cu, Zn, Cd, Pb and As) in 9 surface and subsurface sediment samples from the Lake Acıgöl were analyzed with the bulk and sequential extraction analysis methods by ICP-MS to obtain the metal distribution patterns in this extreme environment. Five stepped sequential extraction technique (1- exchangeable, 2- bond to carbonates, 3- bond to iron and manganese oxides/hydroxides, 4- bond to organic matter and sulphides, and 5- residual fraction incorporated into clay and silicate mineral lattices) was used to characterize the various forms of metals in the <63μ size sediments. The metal contents (ppm) and their percentages for each extraction step were reported and compared with the results obtained from the total digestion. Results indicate that sum of the four fraction are in good agreement with the total digestion results of Ni, Cd, As, Zn, Cu and Fe with the satisfactory recoveries (94.04–109.0%) and the method used is reliable and repeatable for these elements. It was found that there were high correlations between Fe vs. Ni loads in the fraction of F2 and F4 with R2= 0,91 and 0,81, respectively. Comparison of totally 135 chemical analysis results in three sampling location and for 5 fraction between Fe-Co, Co-Ni and Fe-Ni element couples were presented elevated correlations with R2=0,98, 0,92 and 0,91, respectively.

Keywords: Lake Acigol, sequancial extraction, recent lake sediment, geochemical speciation of heavy metals

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Authors: Kali Prasad Sarma, Sanghita Dutta

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Deepor Beel (DB), the lone Ramsar site and an important wetland of the Brahmaputra valley in the state of Assam. The local people from fourteen peripheral villages traditionally utilize the wetland for harvesting vegetables, flowers, aquatic seeds, medicinal plants, fish, molluscs, fodder for domestic cattle etc. Therefore, it is of great importance to understand the concentration and distribution of trace metals in water-sediment system of the beel in order to protect its ecological environment. DB lies between26°05′26′′N to 26°09′26′′N latitudes and 90°36′39′′E to 91°41′25′′E longitudes. Water samples from the surface layer of water up to 40cm deep and sediment samples from the top 5cm layer of surface sediments were collected. The trace metals in waters and sediments were analysed using ICP-OES. The organic Carbon was analysed using the TOC analyser. The different mineral present in the sediments were confirmed by X-ray diffraction method (XRD). SEM images were recorded for the samples using SEM, attached with energy dispersive X-ray unit, with an accelerating voltage of 20 kv. All the statistical analyses were performed using SPSS20.0 for windows. In the present research, distribution, source apportionment, temporal and spatial variability, extent of pollution and the ecological risk of eight toxic trace metals in sediments and water of DB were investigated. The average concentrations of chromium(Cr) (both the seasons), copper(Cu) and lead(Pb) (pre-monsoon) and zinc(Zn) and cadmium(Cd) (post-monsoon) in sediments were higher than the consensus based threshold concentration(TEC). The persistent exposure of toxic trace metals in sediments pose a potential threat, especially to sediment dwelling organisms. The degree of pollution in DB sediments for Pb, Cobalt (Co) Zn, Cd, Cr, Cu and arsenic (As) was assessed using Enrichment Factor (EF), Geo-accumulation index (Igeo) and Pollution Load Index (PLI). The results indicated that contamination of surface sediments in DB is dominated by Pb and Cd and to a lesser extent by Co, Fe, Cu, Cr, As and Zn. A significant positive correlation among the pairs of element Co/Fe, Zn/As in water, and Cr/Zn, Fe/As in sediments indicates similar source of origin of these metals. The effects of interaction among trace metals between water and sediments shows significant variations (F =94.02, P < 0.001), suggesting maximum mobility of trace metals in DB sediments and water. The source apportionment of the heavy metals was carried out using Principal Component Analysis (PCA). SEM-EDS detects the presence of Cd, Cu, Cr, Zn, Pb, As and Fe in the sediment sample. The average concentration of Cd, Zn, Pb and As in the bed sediments of DB are found to be higher than the crustal abundance. The EF values indicate that Cd and Pb are significantly enriched. From source apportionment studies of the eight metals using PCA revealed that Cd was anthropogenic in origin; Pb, As, Cr, and Zn had mixed sources; whereas Co, Cu and Fe were natural in origin.

Keywords: Deepor Beel, enrichment factor, principal component analysis, trace metals

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Authors: Masoud Ghaemi, Mohammadjafar Hedayati, Faezeh Yousefzadeh, Hoseinali Heydarzadeh

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Careful monitoring in the earth dams to measure deformation caused by settlement and movement has always been a concern for engineers in the field. In order to measure settlement and deformation of earth dams, usually, the precision instruments of settlement set and combined Inclinometer that is commonly referred to IS instrument will be used. In some dams, because the thickness of alluvium is high and there is no possibility of alluvium removal (technically and economically and in terms of performance), there is no possibility of placing the end of IS instrument (precision instruments of Inclinometer-settlement set) in the rock foundation. Inevitably, have to accept installing pipes in the weak and deformable alluvial foundation that leads to errors in the calculation of the actual settlement (absolute settlement) in different parts of the dam body. The purpose of this paper is to present new and refine criteria for predicting settlement and deformation in earth dams. The study is based on conditions in three dams with a deformation quite alluvial (Agh Chai, Narmashir and Gilan-e Gharb) to provide settlement criteria affected by the alluvial foundation. To achieve this goal, the settlement of dams was simulated by using the finite difference method with FLAC3D software, and then the modeling results were compared with the reading IS instrument. In the end, the caliber of the model and validate the results, by using regression analysis techniques and scrutinized modeling parameters with real situations and then by using MATLAB software and CURVE FITTING toolbox, new criteria for the settlement based on elasticity modulus, cohesion, friction angle, the density of earth dam and the alluvial foundation was obtained. The results of these studies show that, by using the new criteria measures, the amount of settlement and deformation for the dams with alluvial foundation can be corrected after instrument readings, and the error rate in reading IS instrument can be greatly reduced.

Keywords: earth-fill dam, foundation, settlement, finite difference, MATLAB, curve fitting

Procedia PDF Downloads 171

Authors: Mathewos Temesgen, Lemi Geleta

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Lake Koka is one of the Ethiopian Central Rift Valleys lakes, where the absorbance of domestic, agricultural, and industrial waste from the nearby industrial and agro-industrial activities is very common. The aim of this research was to assess the heavy metal bioaccumulation in edible parts of common carp (Cyprinus carpio) in Lake Koka and the health risks associated with the dietary intake of the fish. Three sampling sites were selected randomly for primary data collection. Physicochemical parameters (pH, Total Dissolved Solids, Dissolved Oxygen and Electrical Conductivity) were measured in-situ. Four heavy metals (Cd, Cr, Pb, and Zn) in water and bio-accumulation in the edible parts of the fish were analyzed with flame atomic absorption spectrometry. The mean values of TDS, EC, DO and pH of the lake water were 458.1 mg/L, 905.7 µ s/cm, 7.36 mg/L, and 7.9, respectively. The mean concentrations of Zn, Cr, and Cd in the edible part of fish were also 0.18 mg/kg, ND-0.24 mg/kg, and ND-0.03 mg/kg, respectively. Pb was, however, not identified. The amount of Cr in the examined fish muscle was above the level set by FAO, and the accumulation of the metals showed marked differences between sampling sites (p<0.05). The concentrations of Cd, Pb and were below the maximum permissible limit. The results also indicated that Cr has a high transfer factor value and Zn has the lowest. The carcinogenic hazard ratio values were below the threshold value (<1) for the edible parts of fish. The estimated weekly intake of heavy metals from fish muscles ranked as Cr>Zn>Cd, but the values were lower than the Reference Dose limit for metals. The carcinogenic risk values indicated a low health risk due to the intake of individual metals from fish. Furthermore, the hazard index of the edible part of fish was less than unity. Generally, the water quality is not a risk for the survival and reproduction of fish, and the heavy metal contents in the edible parts of fish exhibited low carcinogenic risk through the food chain.

Keywords: bio-accumulation, cyprinus carpio, hazard index, heavy metals, Lake Koka

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Authors: Akshay A. Pandya, B. R. Parekh

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This paper presents how earth fault damage in the transformer can be detected by Sweep Frequency Response Analysis (SFRA). The test methods used by the authors for presenting the results are described. The power transformer of rating 10 KVA, 11000 V/440 V, 3-phase, 50 Hz, Dyn11 has been specially developed in-house for carrying out SFRA testing by practically simulated various transformer damages on it. Earth fault has been practically simulated on HV “U” phase winding and LV “W” phase winding separately. The result of these simulated faults are presented and discussed. The motivation of this presented work is to extend the guideline approach; there are ideas to organize database containing collected measurement results. Since the SFRA interpretation is based on experience, such databases are thought to be of great importance when interpreting SFRA response. The evaluation of the SFRA responses against guidelines and experience have to be performed and conclusions regarding usefulness of each simulation has been drawn and at last overall conclusion has also been drawn.

Keywords: earth fault damage, power transformer, practical simulation, SFRA traces, transformer damages

Procedia PDF Downloads 263

Authors: Bernd Engel, Sara Salman Hassan Al-Maeeni

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A substantial amount of natural resources are nowadays consumed at a growing rate, as humans all over the world used materials obtained from the Earth. Machinery manufacturing industry is one of the major resource consumers on a global scale. Even though the incessant finding out of the new material, metals, and resources, it is urgent for the industry to develop methods to use the Earth's resources intelligently and more sustainable than before. Re-engineering of machine tools regarding design and failure analysis is an approach whereby out-of-date machines are upgraded and returned to useful life. To ensure the reliable future performance of the used machine components, it is essential to investigate the machine component failure through the material, design, and surface examinations. This paper presents an experimental approach aimed at inspecting the shaft of the rotary draw bending machine as a case to study. The testing methodology, which is based on the principle of the three-point bending test, allows assessing the shaft elastic behavior under loading. Furthermore, the shaft elastic characteristics include the maximum linear deflection, and maximum bending stress was determined by using an analytical approach and finite element (FE) analysis approach. In the end, the results were compared with the ones obtained by the experimental approach. In conclusion, it is seen that the measured bending deflection and bending stress were well close to the permissible design value. Therefore, the shaft can work in the second life cycle. However, based on previous surface tests conducted, the shaft needs surface treatments include re-carburizing and refining processes to ensure the reliable surface performance.

Keywords: deflection, FE analysis, shaft, stress, three-point bending

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Authors: H. Khomri, A. Bentellis

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Since century of the Development Activities extraction and a dispersed mineral processing Toxic metals and much more contaminated vast areas occupied by what they natural outcrops. New types of metalliferous habitats are so appeared. A species that is Lygeum spartum attracted our curiosity because apart from its valuable role in desertification, it is apparently able to exclude antimony and other metals can be. This species, green leaf blades which are provided as cattle feed, would be a good subject for phytoremediation of mineral soils. The study of absorption and translocation of chromium by the Lygeum spartum in the mining region of Djebel Hamimat and the interaction soil-plant, revealed that soils of this species living in this region are alkaline, calcareous majority in their fine texture medium and saline in their minority. They have normal levels of organic matter. They are moderately rich in nitrogen. They contain total chromium content reaches a maximum of 66,80 mg Kg^(-1) and a total absence of soluble chromium. The results of the analysis of variance of the difference between bare soils and soils appear Lygeum spartum made a significant difference only for the silt and organic matter. But for the other variables analyzed this difference is not significant. Thus, this plant has only one action on the amendment, only the levels of silt and organic matter in soils. The results of the multiple regression of the chromium content of the roots according to all soil variables studied did appear that among the studied variables included in the model, only the electrical conductivity and clay occur in the explanation of contents chromium in roots. The chromium content of the aerial parts analyzed by regression based on all studied soil variables allows us to see only the variables: electrical conductivity and content of chromium in the root portion involved in the explanation of the content chromium in the aerial part.

Keywords: absorption, translocation, analysis of variance, chrome, Lygeum spartum, multiple regression, the soil variables

Procedia PDF Downloads 239

Authors: A. Khalina, K. Shaharuddin, M. S. Wahab, M. P. Saiman, H. A. Aisyah

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This paper investigates the effect of alkali treatment and mechanical properties of kenaf (Hibiscus cannabinus) fibre for the development of yarn. Two different fibre sources are used for the yarn production. Kenaf fibres were treated with sodium hydroxide (NaOH) in the concentration of 3, 6, 9, and 12% prior to fibre opening process and tested for their tensile strength and Young’s modulus. Then, the selected fibres were introduced to fibre opener at three different opening processing parameters; namely, speed of roller feeder, small drum, and big drum. The diameter size, surface morphology, and fibre durability towards machine of the fibres were characterized. The results show that concentrations of NaOH used have greater effects on fibre mechanical properties. From this study, the tensile and modulus properties of the treated fibres for both types have improved significantly as compared to untreated fibres, especially at the optimum level of 6% NaOH. It is also interesting to highlight that 6% NaOH is the optimum concentration for the alkaline treatment. The untreated and treated fibres at 6% NaOH were then introduced to fibre opener, and it was found that the treated fibre produced higher fibre diameter with better surface morphology compared to the untreated fibre. Higher speed parameter during opening was found to produce higher yield of opened-kenaf fibres.

Keywords: alkaline treatment, kenaf fibre, tensile strength, yarn production

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Authors: C. T. Eze, I. N. E. Onwurah

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An important hydrogeologic problem in areas of high faults formations is high environmental health hazard occasioned by microbial and heavy metals contamination of ground waters. Consequently, we examined the microbial load and heavy metals concentration of hospital wastewater discharged into the environment at Park Lane General Hospital Enugu Urban, Nigeria. The microbial counts, characteristics and frequency of occurrences of the isolated microorganisms were determined by cultural, morphological and biochemical characteristics using established procedure while the varying concentrations of the identified heavy metals were determined using the spectrophotometric method. The microbiological analyses showed a mean total aerobic bacteria counts from 13.7 ± 0.65 × 107 to 22.8 ± 1.14 ×1010 CFU/ml, mean total anaerobic bacteria counts from 6.0 ± 1.6 × 103 to 1.7 ± 0.41 ×104 CFU/ml and mean total fungal counts from 0 ± 0 to 2.3 ± 0.16 × 105 CFU/ml. The isolated micro-organisms which included both pathogenic and non-pathogenic organisms were Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Bacillus subtilis, Proteus vulgaris, Klesbsiella pneumonia and bacteriodes sp. The only fungal isolate was Candida albican. The heavy metals identified in the leachate were Arsenic, Cadmium, Lead, Mercury and Chromium and their concentrations ranged from 0.003 ± 0.00082 to 0.14 ± 0.0082 mg/l. These values were above WHO permissible limits while others fall within the limits. Therefore, hospital waste water can pose the environmental health risk when not properly treated before discharge, especially in geologic formations with high fault formations.

Keywords: bacterial isolates, fungal isolates, heavy metals, hospital wastewater, microbial counts

Procedia PDF Downloads 325