Search results for: gaseous pollutants

Authors: Matt S. Van Deren, Michael Papenfus

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Seattle is one of the hundreds of cities in the United States that relies on a combined sewer system to collect and convey municipal wastewater. By design, these systems convey all wastewater, including industrial and commercial wastewater, human sewage, and stormwater runoff, through a single network of pipes. Serious problems arise for combined sewer systems during heavy precipitation events when treatment plants and storage facilities are unable to accommodate the influx of wastewater needing treatment, causing the sewer system to overflow into local waterways through sewer outfalls. CSOs (Combined Sewer Overflows) pose a serious threat to human and environmental health. Principal pollutants found in CSO discharge include microbial pathogens, comprising of bacteria, viruses, parasites, oxygen-depleting substances, suspended solids, chemicals or chemical mixtures, and excess nutrients, primarily nitrogen and phosphorus. While concentrations of these pollutants can vary between overflow events, CSOs have the potential to spread disease and waterborne illnesses, contaminate drinking water supplies, disrupt aquatic life, and effect a waterbody’s designated use. This paper estimates the economic impact of CSOs on residential property values. Using residential property sales data from Seattle, Washington, this paper employs a hedonic valuation model that controls for housing and neighborhood characteristics, as well as spatial and temporal effects, to predict a consumer’s willingness to pay for improved water quality near their homes. Initial results indicate that a 100,000-gallon decrease in the average annual overflow discharged from a sewer outfall within 300 meters of a home is associated with a 0.053% increase in the property’s sale price. For the average home in the sample, the price increase is estimated to be $18,860.23. These findings reveal some of the important economic benefits of improving water quality by reducing the frequency and severity of combined sewer overflows.

Keywords: benefits, hedonic, Seattle, sewer

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Authors: Chandrasekaran, Ravisankar N. Harikrishnan, Rajalakshmi, K. K. Satapathy M. V. R. Prasad, K. V. Kanagasabapathy

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Heavy metals were considered as highly toxic environmental pollutants to soil ecosystem and human health. In present study the 12 heavy metals (Mg, Al, K, Ca, Ti, Fe, V, Cr, Mn, Co,Ni and Zn.) are determined in soils of Yelagiri hills, Tamilnadu by energy dispersive X-ray fluorescence technique. Metal concentrations were used to quantify pollution contamination factors such as enrichment factor (EF), geo-accumulation index (Igeo) and contamination factor (CF) are calculated and reported.

Keywords: soil, heavy metals, EDXRF, pollution contamination factors

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Authors: Glauco M. M. M. Lustosa, João Paulo C. Costa, Sonia M. Zanetti, Mario Cilense, Leinig Antônio Perazolli, Maria Aparecida Zaghete

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The contamination of the environment has been one of the biggest problems of our time, mostly due to developments of many industries. SnO2 is an n-type semiconductor with band gap about 3.5 eV and has its electrical conductivity dependent of type and amount of modifiers agents added into matrix ceramic during synthesis process, allowing applications as sensing of gaseous pollutants on ambient. The chemical synthesis by polymeric precursor method consists in a complexation reaction between tin ion and citric acid at 90 °C/2 hours and subsequently addition of ethyleneglycol for polymerization at 130 °C/2 hours. It also prepared polymeric resin of zinc, cobalt and niobium ions. Stoichiometric amounts of the solutions were mixed to obtain the systems (Zn, Nb)-SnO2 and (Co, Nb) SnO2 . The metal immobilization reduces its segregation during the calcination resulting in a crystalline oxide with high chemical homogeneity. The resin was pre-calcined at 300 °C/1 hour, milled in Atritor Mill at 500 rpm/1 hour, and then calcined at 600 °C/2 hours. X-Ray Diffraction (XDR) indicated formation of SnO2 -rutile phase (JCPDS card nº 41-1445). The characterization by Scanning Electron Microscope of High Resolution showed spherical ceramic powder nanostructured with 10-20 nm of diameter. 20 mg of SnO2 -based powder was kept in 20 ml of isopropyl alcohol and then taken to an electrophoretic deposition (EPD) system. The EPD method allows control the thickness films through the voltage or current applied in the electrophoretic cell and by the time used for deposition of ceramics particles. This procedure obtains films in a short time with low costs, bringing prospects for a new generation of smaller size devices with easy integration technology. In this research, films were obtained in an alumina substrate with interdigital electrodes after applying 2 kV during 5 and 10 minutes in cells containing alcoholic suspension of (Zn, Nb)-SnO2 and (Co, Nb) SnO2 of powders, forming a sensing layer. The substrate has designed integrated micro hotplates that provide an instantaneous and precise temperature control capability when a voltage is applied. The films were sintered at 900 and 1000 °C in a microwave oven of 770 W, adapted by the research group itself with a temperature controller. This sintering is a fast process with homogeneous heating rate which promotes controlled growth of grain size and also the diffusion of modifiers agents, inducing the creation of intrinsic defects which will change the electrical characteristics of SnO2 -based powders. This study has successfully demonstrated a microfabricated system with an integrated micro-hotplate for detection of CO and NO2 gas at different concentrations and temperature, with self-heating SnO2 - based nanoparticles films, being suitable for both industrial process monitoring and detection of low concentrations in buildings/residences in order to safeguard human health. The results indicate the possibility for development of gas sensors devices with low power consumption for integration in portable electronic equipment with fast analysis. Acknowledgments The authors thanks to the LMA-IQ for providing the FEG-SEM images, and the financial support of this project by the Brazilian research funding agencies CNPq, FAPESP 2014/11314-9 and CEPID/CDMF- FAPESP 2013/07296-2.

Keywords: chemical synthesis, electrophoretic deposition, self-heating, gas sensor

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Authors: Yuvraj S. Malghe, Atul B. Lavand

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In recent years, semiconductor photocatalytic degradation processes have attracted a lot of attention and are used widely for the destruction of organic pollutants present in waste water. Among various semiconductors, titanium dioxide (TiO2) is the most popular photocatalyst due to its excellent chemical stability, non-toxicity, relatively low cost and high photo-oxidation power. It has been known that zinc oxide (ZnO) with band gap energy 3.2 eV is a suitable alternative to TiO2 due to its high quantum efficiency, however it corrodes in acidic medium. Unfortunately TiO2 and ZnO both are active only in UV light due to their wide band gaps. Sunlight consist about 5-7% UV light, 46% visible light and 47% infrared radiation. In order to utilize major portion of sunlight (visible spectrum), it is necessary to modify the band gap of TiO2 as well as ZnO. This can be done by several ways such as semiconductor coupling, doping the material with metals/non metals. Doping of TiO2 using transition metals like Fe, Co and non-metals such as N, C or S extends its absorption wavelengths from UV to visible region. In the present work, we have synthesized ZnO-TiO2 nanocomposite using reverse microemulsion method. Visible light photocatalytic activity of synthesized nanocomposite was investigated for degradation of aqueous solution of malachite green (MG). To increase the photocatalytic activity of ZnO-TiO2 nanocomposite, it is decorated with C and Fe. Pure, carbon (C) doped and carbon, iron(C, Fe) co-doped nanosized ZnO-TiO2 nanocomposites were synthesized using reverse microemulsion method. These composites were characterized using, X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), Scanning electron microscopy (SEM), UV visible spectrophotometery and X-ray photoelectron spectroscopy (XPS). Visible light photocatalytic activities of synthesized nanocomposites were investigated for degradation of aqueous malachite green (MG) solution. C, Fe co-doped ZnO-TiO2 nanocomposite exhibit better photocatalytic activity and showed threefold increase in photocatalytic activity. Effect of amount of catalyst, pH and concentration of MG solution on the photodegradation rate is studied. Stability and reusability of photocatalyst is also studied. C, Fe decorated ZnO-TiO2 nanocomposite shows threefold increase in photocatalytic activity.

Keywords: malachite green, nanocomposite, photocatalysis, titanium dioxide, zinc oxide

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Authors: Faisal Saleem, Kui Zhang, Adam Harvey

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The role of N₂ carrier gas towards the conversion of tar analogue was studied in a non-thermal plasma dielectric barrier discharge (DBD) reactor. The important parameters such as power (5-40W), residence time (1.41-4.23 s), concentration (20-82 g/Nm³), and temperature (Ambient-400°C) were explored. The present study demonstrated that plasma power and residence time played a key role in the decomposition of toluene, and almost complete removal of toluene was observed at 40w and 4.23 s. H₂ is obtained as a major gaseous product with a maximum selectivity of 40% along with some lighter hydrocarbons (5.5%). The removal efficiency of toluene slightly decreases with increasing the concentration of toluene from 20 g/Nm³ to 82 g/Nm³. The solid residue formation takes place inside the plasma reactor. The selectivity of LHC (lower hydrocarbons) increased up to 15% by increasing the temperature to 400°C. Introducing H₂ to the gas at elevated temperature opens up new reaction routes to raise the selectivity to lower hydrocarbons. The selectivity to methane reaches to 42% using 35% H₂ at 400°C and total selectivity of LHC increases to 57%.

Keywords: biomass gasification tar, non-thermal plasma, dielectric barrier discharge, residence time

Procedia PDF Downloads 161

Authors: Inês Amorim Leitão, Loes van Shaick, António Dinis Ferreira, Violette Geissen

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Plastic pollution is a growing concern worldwide: plastics are commercialized in large quantities and it takes a long time for them to degrade. When in the environment, plastic is fragmented into microplastics (<5mm), which have been found in all environmental compartments at different locations. Microplastics contribute to the environmental pollution in water, air and soil and are linked to human health problems. The progressive increase of population living in cities led to the aggravation of the pollution problem worldwide, especially in urban environments. Urban areas represent a strong source of pollution, through the roads, industrial production, wastewater, landfills, etc. It is expected that pollutants such as microplastics are transported diffusely from the sources through different pathways such as wind and rain. Therefore, it is very complex to quantify, control and treat these pollutants, designated current problematic issues by the European Commission. Green areas are pointed out by experts as natural filters for contaminants in cities, through their capacity of retention by vegetation. These spaces have thus the capacity to control the load of pollutants transported. This study investigates the spatial distribution of microplastics in urban soils of different land uses, their transport through atmospheric deposition, wind erosion, runoff and streams, as well as their deposition in vegetation like grass and tree leaves in urban environment. Coimbra, a medium large city located in the central Portugal, is the case-study. All the soil, sediments, water and vegetation samples were collected in Coimbra and were later analyzed in the Wageningen University & Research laboratory. Microplastics were extracted through the density separation using Sodium Phosphate as solution (~1.4 g cm−3) and filtration methods, visualized under a stereo microscope and identified using the u-FTIR method. Microplastic particles were found in all the different samples. In terms of soils, higher concentrations of microplastics were found in green parks, followed by landfills and industrial places, and the lowest concentrations in forests and pasture land-uses. Atmospheric deposition and streams after rainfall events seems to represent the strongest pathways of microplastics. Tree leaves can retain microplastics on their surfaces. Small leaves such as needle leaves seem to present higher amounts of microplastics per leaf area than bigger leaves. Rainfall episodes seem to reduce the concentration of microplastics on leaves surface, which suggests the wash of microplastics down to lower levels of the tree or to the soil. When in soil, different types of microplastics could be transported to the atmosphere through wind erosion. Grass seems to present high concentrations of microplastics, and the enlargement of the grass cover leads to a reduction of the amount of microplastics in soil, but also of the microplastics moved from the ground to the atmosphere by wind erosion. This study proof that vegetation can help to control the transport and dispersion of microplastics. In order to control the entry and the concentration of microplastics in the environment, especially in cities, it is essential to defining and evaluating nature-based land-use scenarios, considering the role of green urban areas in filtering small particles.

Keywords: microplastics, cities, sources, pathways, vegetation

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Authors: Zh. Saffari, A. Naeimi, M. S. Ekrami-Kakhki, Kh. Khandan-Barani

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The textile industries are becoming a major source of environmental contamination because an alarming amount of dye pollutants are generated during the dyeing processes. Organic dyes are one of the largest pollutants released into wastewater from textile and other industrial processes, which have shown severe impacts on human physiology. Nano-structure compounds have gained importance in this category due their anticipated high surface area and improved reactive sites. In recent years several novel adsorbents have been reported to possess great adsorption potential due to their enhanced adsorptive capacity. Nano-MnO2 has great potential applications in environment protection field and has gained importance in this category because it has a wide variety of structure with large surface area. The diverse structures, chemical properties of manganese oxides are taken advantage of in potential applications such as adsorbents, sensor catalysis and it is also used for wide catalytic applications, such as degradation of dyes. In this study, adsorption of Methyl Violet (MV) dye from aqueous solutions onto MnO2 nanoparticles (MNP) has been investigated. The surface characterization of these nano particles was examined by Particle size analysis, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diffraction (XRD). The effects of process parameters such as initial concentration, pH, temperature and contact duration on the adsorption capacities have been evaluated, in which pH has been found to be most effective parameter among all. The data were analyzed using the Langmuir and Freundlich for explaining the equilibrium characteristics of adsorption. And kinetic models like pseudo first- order, second-order model and Elovich equation were utilized to describe the kinetic data. The experimental data were well fitted with Langmuir adsorption isotherm model and pseudo second order kinetic model. The thermodynamic parameters, such as Free energy of adsorption (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) were also determined and evaluated.

Keywords: MnO2 nanoparticles, adsorption, methyl violet, isotherm models, kinetic models, surface chemistry

Procedia PDF Downloads 234

Authors: Thanaa Abdel Moghny, Mohamed Keshawy, Mahmoud Fathy, Abdul-Raheim M. Abdul-Raheim, Khalid I. Kabel, Ahmed F. El-Kafrawy, Mahmoud Ahmed Mousa, Ahmed E. Awadallah

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Ecological pollution is of great concern for human health and the environment. Numerous organic and inorganic pollutants usually discharged into the water caused carcinogenic or toxic effect for human and different life form. In this respect, this work aims to treat water contaminated by organic and inorganic waste using sorbent based on polystyrene. Therefore, two different series of adsorbent material were prepared; the first one included the preparation of polymeric sorbent from the reaction of styrene acrylate ester and alkyl acrylate. The second series involved syntheses of composite ion exchange resins of waste polystyrene and   amorphous carbon thin film (WPS/ACTF) by solvent evaporation using micro emulsion polymerization. The produced ACTF/WPS nanocomposite was sulfonated to produce cation exchange resins ACTF/WPSS nanocomposite. The sorbents of the first series were characterized using FTIR, ¹H NMR, and gel permeation chromatography. The thermal properties of the cross-linked sorbents were investigated using thermogravimetric analysis, and the morphology was characterized by scanning electron microscope (SEM). The removal of organic pollutant was determined through absorption tests in a various organic solvent. The chemical and crystalline structure of nanocomposite of second series has been proven by studies of FTIR spectrum, X-rays, thermal analysis, SEM and TEM analysis to study morphology of resins and ACTF that assembled with polystyrene chain. It is found that the composite resins ACTF/WPSS are thermally stable and show higher chemical stability than ion exchange WPSS resins. The composite resin was evaluated for calcium hardness removal. The result is evident that the ACTF/WPSS composite has more prominent inorganic pollutant removal than WPSS resin. So, we recommend the using of nanocomposite resin as new potential applications for water treatment process.

Keywords: nanocomposite, sorbent materials, waste water, waste polystyrene

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Authors: Wooseok Song, Sunjung Park, Jongkwon Lee, Jaye Koo

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The objective of this paper is to observe the effects of injection conditions on flame structures in gas-centered swirl coaxial injector. Gaseous oxygen and liquid kerosene were used as propellants. For different injection conditions, two types of injector, which only differ in the diameter of the tangential inlet, were used in this study. In addition, oxidizer injection pressure was varied to control the combustion chamber pressure in different types of injector. In order to analyze the combustion instability intensity, the dynamic pressure was measured in both the combustion chamber and propellants lines. With the increase in differential pressure between the propellant injection pressure and the combustion chamber pressure, the combustion instability intensity increased. In addition, the flame structure was recorded using a high-speed camera to detect CH* chemiluminescence intensity. With the change in the injection conditions in the gas-centered swirl coaxial injector, the flame structure changed.

Keywords: liquid rocket engine, flame structure, combustion instability, dynamic pressure

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Authors: M. S. Abd El-Sadek, M. A. Omar, Gharib M. Taha

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In recent years, photocatalytic degradation of various kinds of organic and inorganic pollutants using semiconductor powders as photocatalysts has been extensively studied. Owing to its relatively high photocatalytic activity, biological and chemical stability, low cost, nonpoisonous and long stable life, Tin oxide materials have been widely used as catalysts in chemical reactions, including synthesis of vinyl ketone, oxidation of methanol and so on. Tin oxide (SnO₂), with a rutile-type crystalline structure, is an n-type wide band gap (3.6 eV) semiconductor that presents a proper combination of chemical, electronic and optical properties that make it advantageous in several applications. In the present work, SnO₂ nanoparticles were synthesized at room temperature by the sol-gel process and thermohydrolysis of SnCl₂ in isopropanol by controlling the crystallite size through calculations. The synthesized nanoparticles were identified by using XRD analysis, TEM, FT-IR, and Uv-Visible spectroscopic techniques. The crystalline structure and grain size of the synthesized samples were analyzed by X-Ray diffraction analysis (XRD) and the XRD patterns confirmed the presence of tetragonal phase SnO₂. In this study, Methylene blue degradation was tested by using SnO₂ nanoparticles (at different calculations temperatures) as a photocatalyst under sunlight as a source of irradiation. The results showed that the highest percentage of degradation of Methylene blue dye was obtained by using SnO₂ photocatalyst at calculations temperature 800 ᵒC. The operational parameters were investigated to be optimized to the best conditions which result in complete removal of organic pollutants from aqueous solution. It was found that the degradation of dyes depends on several parameters such as irradiation time, initial dye concentration, the dose of the catalyst and the presence of metals such as silver as a dopant and its concentration. Percent degradation was increased with irradiation time. The degradation efficiency decreased as the initial concentration of the dye increased. The degradation efficiency increased as the dose of the catalyst increased to a certain level and by further increasing the SnO₂ photocatalyst dose, the degradation efficiency is decreased. The best degradation efficiency on which obtained from pure SnO₂ compared with SnO₂ which doped by different percentage of Ag.

Keywords: SnO₂ nanoparticles, a sol-gel method, photocatalytic applications, methylene blue, degradation efficiency

Procedia PDF Downloads 124

Authors: Li Feng, Cheng Zhang, Chuanzhou Yuang

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Understanding the macromolecular structure of low-rank coal is very important for its gasification and liquefaction. The pyrolysis is one of the methods of analyzing the macromolecular structure of coal. The gaseous products decomposed directly by the raw lignite at 500 °C and indirectly by tar products from raw lignite pyrolysis at 500 °C were investigated and compared by thermogravimetry, gas chromatography and mass spectrum coupled instrument system (TG/GC/MS) in this paper. The results show that 52 kinds of products were found from the raw lignite and 70 kinds of products from the tar. The pyrolysis products directly from the lignite appear more monocyclic aromatic hydrocarbons and less substituent groups or branch chain, compared with the products from the tar. There is less linear chain and double bonds structure in the tar, which can be speculated that linear chain and double bonds structure took part in the generation of condensed rings and other reactions. There are more kinds of phenol and furan in the tar, which indicate that these products may be generated from the secondary reaction. The formation process of phenol, phenol naphthalene, naphthene and furan are discussed.

Keywords: composition and structure, lignite, pyrolysis of coal, tar, TG/GC/MS

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Authors: Latifa Sabri, Mohammed Benzirar, Mimoun Zazoui

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The installation of photovoltaic systems is one of future sources to generate electricity without emitting pollutants. The photovoltaic cells used in these systems have demonstrated enormous efficiencies and advantages. Several researches have discussed the maximum efficiency of these technologies, but only a few experiences have succeeded to right weather conditions to get these results. In this paper, two types of cells were selected: crystalline and amorphous silicon. Using the method of genetic algorithm, the results show that for an ambient temperature of 25°C and direct irradiation of 625 W/m², the efficiency of crystalline silicon is 12% and 5% for amorphous silicon.

Keywords: PV, maximum efficiency, solar cell, genetic algorithm

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Authors: V. S. Bessa, I. S. Moreira, S. Murgolo, C. Piccirillo, G. Mascolo, P. M. L. Castro

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The occurrence of pharmaceuticals in the environment has been a topic of increasing concern. Pharmaceuticals are not completely mineralized in the human body and are released on the sewage systems as the pharmaceutical itself and as their “biologically active” metabolites through excretion, as well as by improper elimination and disposal. Conventional wastewater treatment plants (WWTPs) are not designed to remove these emerging pollutants and they are thus released into the environment. The antiepileptic drug carbamazepine (CBZ) and the non-steroidal anti-inflammatory diclofenac (DCF) are two widely used pharmaceuticals, frequently detected in water bodies, including rivers and groundwater, in concentrations ranging from ng L 1 to mg L 1. These two compounds were classified as medium to high-risk pollutants in WWTP effluents and surface waters. Also, CBZ has been suggested as a molecular marker of wastewater contamination in surface water and groundwater and the European Union included DCF in the watch list of substances Directive to be monitored. In the present study, biodegradation of CBZ and DCF by the bacterial strain Labrys portucalensis F11, a strain able to degrade other pharmaceutical compounds, was assessed; tests were performed with F11 as single carbon and energy source, as well as in presence of 5.9mM of sodium acetate. In assays supplemented with 2.0 and 4.0 µM of CBZ, the compound was no longer detected in the bulk medium after 24hr and 5days, respectively. Complete degradation was achieved in 21 days for 11.0 µM and in 23 days for 21.0 µM. For the highest concentration tested (43.0 µM), 95% of degradation was achieved in 30days. Supplementation with acetate increased the degradation rate of CBZ, for all tested concentrations. In the case of DCF, when supplemented as a single carbon source, approximately 70% of DCF (1.7, 3.3, 8.4, 17.5 and 34.0 µM) was degraded in 30days. Complete degradation was achieved in the presence of acetate for all tested concentrations, at higher degradation rates. The detection of intermediates produced during DCF biodegradation was performed by UPLC-QTOF/MS/MS, which allowed the identification of a range of metabolites. Stoichiometric liberation of chorine occurred and no metabolites were detected at the end of the biodegradation assays suggesting a complete mineralization of DCF. Strain Labrys portucalensis F11 proved to be able to degrade these two top priority environmental contaminants and may be potentially useful for biotechnological applications/environment remediation.

Keywords: biodegradation, carbamazepine, diclofenac, pharmaceuticals

Procedia PDF Downloads 241

Authors: Tony K. Joseph, Balasubramanian Vathilingam, Stephane Morin

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Currently, the refiners around the world are more focused on improving the yield of light olefins (propylene and ethylene) as both of them are very prominent raw materials to produce wide spectrum of polymeric materials such as polyethylene and polypropylene. Henceforth, it is desirable to increase the yield of light olefins via selective cracking of heavy oil fractions. In this study, zeolite grown on SiC was used as the catalyst to do model cracking reaction of n-heptane. The catalytic cracking of n-heptane was performed in a fixed bed reactor (12 mm i.d.) at three different temperatures (425, 450 and 475 °C) and at atmospheric pressure. A carrier gas (N₂) was mixed with n-heptane with ratio of 90:10 (N₂:n-heptane), and the gaseous mixture was introduced into the fixed bed reactor. Various flow rate of reactants was tested to increase the yield of ethylene and propylene. For the comparison purpose, commercial zeolite was also tested in addition to Zeolite on SiC. The products were analyzed using an Agilent gas chromatograph (GC-9860) equipped with flame ionization detector (FID). The GC is connected online with the reactor and all the cracking tests were successfully reproduced. The entire catalytic evaluation results will be presented during the conference.

Keywords: cracking, catalyst, evaluation, ethylene, heptane, propylene

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Authors: Zakia Hbellaq

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The Mediterranean region is considered a hotbed for climate change. Morocco is a semi-arid Mediterranean country facing water shortages and poor water quality. Its limited water resources limit the activities of various economic sectors. Most of Morocco's territory is in arid and desert areas. The potential water resources are estimated at 22 billion m3, which is equivalent to about 700 m3/inhabitant/year, and Morocco is in a state of structural water stress. Strictly speaking, the Kingdom of Morocco is one of the “very riskiest” countries, according to the World Resources Institute (WRI), which oversees the calculation of water stress risk in 167 countries. The surprising results of the Institute (WRI) rank Morocco as one of the riskiest countries in terms of water scarcity, ranking 3.89 out of 5, thus occupying the 23rd place out of a total of 167 countries, which indicates that the demand for water exceeds the available resources. Agriculture with a score of 3.89 is most affected by water stress from irrigation and places a heavy burden on the water table. Irrigation is an unavoidable technical need and has undeniable economic and social benefits given the available resources and climatic conditions. Irrigation, and therefore the agricultural sector, currently uses 86% of its water resources, while industry uses 5.5%. Although its development has undeniable economic and social benefits, it also contributes to the overfishing of most groundwater resources and the surprising decline in levels and deterioration of water quality in some aquifers. In this context, REUSE is one of the proposed solutions to reduce the water footprint of the agricultural sector and alleviate the shortage of water resources. Indeed, wastewater reuse, also known as REUSE (reuse of treated wastewater), is a step forward not only for the circular economy but also for the future, especially in the context of climate change. In particular, water reuse provides an alternative to existing water supplies and can be used to improve water security, sustainability, and resilience. However, given the introduction of organic trace pollutants or, organic micro-pollutants, the absorption of emerging contaminants, and decreasing salinity, it is possible to tackle innovative capabilities to overcome these problems and ensure food and health safety. To this end, attention will be paid to the adoption of an integrated and attractive approach, based on the reinforcement and optimization of the treatments proposed for the elimination of the organic load with particular attention to the elimination of emerging pollutants, to achieve this goal. , membrane bioreactors (MBR) as stand-alone technologies are not able to meet the requirements of WHO guidelines. They will be combined with heterogeneous Fenton processes using persulfate or hydrogen peroxide oxidants. Similarly, adsorption and filtration are applied as tertiary treatment In addition, the evaluation of crop performance in terms of yield, productivity, quality, and safety, through the optimization of Trichoderma sp strains that will be used to increase crop resistance to abiotic stresses, as well as the use of modern omics tools such as transcriptomic analysis using RNA sequencing and methylation to identify adaptive traits and associated genetic diversity that is tolerant/resistant/resilient to biotic and abiotic stresses. Hence, ensuring this approach will undoubtedly alleviate water scarcity and, likewise, increase the negative and harmful impact of wastewater irrigation on the condition of crops and the health of their consumers.

Keywords: water scarcity, food security, irrigation, agricultural water footprint, reuse, emerging contaminants

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Authors: Gómez R. Marta, Martín M. Jesús María

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The general aim of this paper identifies the areas of highest concentration of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) around the incinerator through the use of dispersion models. Atmospheric dispersion models are useful tools for estimating and prevent the impact of emissions from a particular source in air quality. These models allow considering different factors that influence in air pollution: source characteristics, the topography of the receiving environment and weather conditions to predict the pollutants concentration. The PCDD/Fs, after its emission into the atmosphere, are deposited on water or land, near or far from emission source depending on the size of the associated particles and climatology. In this way, they are transferred and mobilized through environmental compartments. The modelling of PCDD/Fs was carried out with following tools: Atmospheric Dispersion Model Software (ADMS) and Surfer. ADMS is a dispersion model Gaussian plume, used to model the impact of air quality industrial facilities. And Surfer is a program of surfaces which is used to represent the dispersion of pollutants on a map. For the modelling of emissions, ADMS software requires the following input parameters: characterization of emission sources (source type, height, diameter, the temperature of the release, flow rate, etc.) meteorological and topographical data (coordinate system), mainly. The study area was set at 5 Km around the incinerator and the first population center nearest to focus PCDD/Fs emission is about 2.5 Km, approximately. Data were collected during one year (2013) both PCDD/Fs emissions of the incinerator as meteorology in the study area. The study has been carried out during period's average that legislation establishes, that is to say, the output parameters are taking into account the current legislation. Once all data required by software ADMS, described previously, are entered, and in order to make the representation of the spatial distribution of PCDD/Fs concentration and the areas affecting them, the modelling was proceeded. In general, the dispersion plume is in the direction of the predominant winds (Southwest and Northeast). Total levels of PCDD/Fs usually found in air samples, are from <2 pg/m3 for remote rural areas, from 2-15 pg/m3 in urban areas and from 15-200 pg/m3 for areas near to important sources, as can be an incinerator. The results of dispersion maps show that maximum concentrations are the order of 10-8 ng/m3, well below the values considered for areas close to an incinerator, as in this case.

Keywords: atmospheric dispersion, dioxin, furan, incinerator

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Authors: S. Bouafia Chergui, Nihal Oturan, Hussein Khalaf, Mehmet A. Oturan

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The aim of this work was to compare the degradation of a mixture of three cationic dyes by advanced oxidation processes (electro-Fenton, photo-Fenton) in aqueous solution. These processes are based on the in situ production of hydroxyl radical, a highly strong oxidant, which allows the degradation of organic pollutants until their mineralization into CO2 and H2O. Under optimal operating conditions, the evolution of total organic carbon (TOC) and electrical energy efficiency have been investigated for the two processes.

Keywords: photo-fenton, electro-fenton, energy efficiency, water treatment

Procedia PDF Downloads 475

Authors: Kianoosh Shojae

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In recent years, the environmental challenges due to the excessive use of fossil fuels have led to heightened greenhouse gas production. In response, biodiesel has emerged as a cleaner alternative, offering reduced pollutant emissions compared to traditional fuels. The large-scale production of biodiesel, involving ester exchange of animal fats or vegetable oils, results in a surplus of crude glycerin. With environmental regulations on the rise and an increasing demand for biodiesel, glycerin production has seen a significant upswing. This paper focuses on the economic significance of glycerin through its pyrolysis as a raw material, particularly in the synthesis of metals. As industries pivoted towards cleaner fuels, glycerin, as a byproduct of biodiesel production, is poised to remain a cost-effective and surplus product. In this work, for evaluating the possible performance of using the gaseous products from the pyrolysis reaction of glycerol, we concerned the glycerin pyrolysis reactions, emphasizing the catalytic role of activated carbon, various reaction pathways and the impact of carrier gas flow rate on hydrogen production, providing valuable insights into the evolving landscape of sustainable fuel alternatives.

Keywords: biodiesel, glycerin pyrolysis, activated carbon catalysis, syngas

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Authors: Liliana Patricia Olivo Arias

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The present study focused on the hydrodynamic study in a three-phase fluidized bed reactor and the influence of important aspects, such as volume fractions (Hold up), velocity magnitude of gas, liquid and solid phases (hydrogen, gasoil, and gamma alumina), interactions of phases, through of drag models with the k-epsilon turbulence model. For this purpose was employed a Euler-Euler model and also considers the system is constituted of three phases, gaseous, liquid and solid, characterized by its physical and thermal properties, the transport processes that are developed within the transient regime. The proposed model of the three-phase fluidized bed reactor was solved numerically using the ANSYS-Fluent software with different mesh refinements on bed expansion zone in order to observe the influence of the hydrodynamic parameters and convergence criteria. With this model and the numerical simulations obtained for its resolution, it was possible to predict the results of the volume fractions (Hold ups) and the velocity magnitude for an unsteady system from the initial and boundaries conditions were established.

Keywords: three-phase fluidized bed system, CFD simulation, mesh dependency study, hydrodynamic study

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Authors: Massimiliano Condotta, Paolo Ruggeri, Chiara Scanagatta, Giovanni Borga

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Architects and urban planners, when designing and renewing cities, have to face a complex set of problems, including the issues of noise and air pollution which are considered as hot topics (i.e., the Clean Air Act of London and the Soundscape definition). It is usually taken for granted that these problems go by together because the noise pollution present in cities is often linked to traffic and industries, and these produce air pollutants as well. Traffic congestion can create both noise pollution and air pollution, because NO₂ is mostly created from the oxidation of NO, and these two are notoriously produced by processes of combustion at high temperatures (i.e., car engines or thermal power stations). We can see the same process for industrial plants as well. What have to be investigated – and is the topic of this paper – is whether or not there really is a correlation between noise pollution and air pollution (taking into account NO₂) in urban areas. To evaluate if there is a correlation, some low-cost methodologies will be used. For noise measurements, the OpeNoise App will be installed on an Android phone. The smartphone will be positioned inside a waterproof box, to stay outdoor, with an external battery to allow it to collect data continuously. The box will have a small hole to install an external microphone, connected to the smartphone, which will be calibrated to collect the most accurate data. For air, pollution measurements will be used the AirMonitor device, an Arduino board to which the sensors, and all the other components, are plugged. After assembling the sensors, they will be coupled (one noise and one air sensor) and placed in different critical locations in the area of Mestre (Venice) to map the existing situation. The sensors will collect data for a fixed period of time to have an input for both week and weekend days, in this way it will be possible to see the changes of the situation during the week. The novelty is that data will be compared to check if there is a correlation between the two pollutants using graphs that should show the percentage of pollution instead of the values obtained with the sensors. To do so, the data will be converted to fit on a scale that goes up to 100% and will be shown thru a mapping of the measurement using GIS methods. Another relevant aspect is that this comparison can help to choose which are the right mitigation solutions to be applied in the area of the analysis because it will make it possible to solve both the noise and the air pollution problem making only one intervention. The mitigation solutions must consider not only the health aspect but also how to create a more livable space for citizens. The paper will describe in detail the methodology and the technical solution adopted for the realization of the sensors, the data collection, noise and pollution mapping and analysis.

Keywords: air quality, data analysis, data collection, NO₂, noise mapping, noise pollution, particulate matter

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Authors: D. Makuteniene

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Agriculture, as one of the human activities, emits a significant amount of greenhouse gas emission and undoubtedly has an impact on climate change. The main gaseous products of agricultural greenhouse gases are carbon dioxide, methane, and nitroxadoxide. The sources and emission of these gases depend on land use, soil, crops, manure, livestock, and energy consumption. One of the indicators showing the agricultural impact on climate change is an intensity of GHG emission and its dynamics. This study analyzed the determinants of an intensity of greenhouse gas emission in Lithuanian agriculture using data decomposition. The research revealed that, although greenhouse gas emission increased during the research period, however, agricultural net value added grew more rapidly, which contributed to a reduction of intensity of greenhouse gas emission in Lithuania between 2000 and 2015. It was identified that during the research period intensity of greenhouse gas emission was mostly increased by the change of the use of nitrogen in agriculture, as compared to the change of the area of agricultural land, and by the change of the number of full-time employees, as compared to the change of net value added. Conversely, the change of energy consumption in agriculture, as compared to the change of the use of nitrogen in agriculture, had a bigger impact in decreasing intensity of greenhouse gas emission.

Keywords: agriculture, determinants of intensity, greenhouse gas emission, intensity

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Authors: Vipan Kumar Sohpal, Rajesh Kumar Sharma

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Thermo-chemical conversion of non-edible biomass offers an efficient and economically process to provide valuable fuels and prepare chemicals derived from biomass in the context of developing countries. Pyrolysis has advantages over other thermochemical conversion techniques because it can convert biomass directly into solid, liquid and gaseous products by thermal decomposition of biomass in the absence of oxygen. The present paper aims to focus on the slow thermochemical conversion processes for non-edible Jatropha curcus seed cake. The present discussion focuses on the effect of nitrogen gas flow rate on products composition (wt %). In addition, comparative analysis has been performed for different mesh size for product composition. Result shows that, slow pyrolysis experiments of Jatropha curcus seed cake in fixed bed reactor yield the bio-oil 18.42 wt % at a pyrolysis temperature of 500°C, particle size of -6+8 mesh number and nitrogen gas flow rate of 150 ml/min.

Keywords: Jatropha curcus, thermo-chemical, pyrolysis, product composition, yield

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Authors: Merouane Salhi, Toufik Zebbiche

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When the stagnation pressure of perfect gas increases, the specific heat and their ratio do not remain constant anymore and start to vary with this pressure. The gas doesn’t remain perfect. Its state equation change and it becomes for a real gas. In this case, the effects of molecular size and intermolecular attraction forces intervene to correct the state equation. The aim of this work is to show and discuss the effect of stagnation pressure on supersonic thermodynamical, physical and geometrical flow parameters, to find a general case for real gas. With the assumptions that Berthelot’s state equation accounts for the molecular size and intermolecular force effects, expressions are developed for analyzing supersonic flow for thermally and calorically imperfect gas lower than the dissociation molecules threshold. The designs parameters for supersonic nozzle like thrust coefficient depend directly on stagnation parameters of the combustion chamber. The application is for air. A computation of error is made in this case to give a limit of perfect gas model compared to real gas model.

Keywords: supersonic flow, real gas model, Berthelot’s state equation, Simpson’s method, condensation function, stagnation pressure

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Authors: Mohammedi Ferhate, Hakim Chadli, Laggoun Chaouki

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The main objectives of work in this area are, first, obtaining the high laser energies in short time durations needed for the feasibility studies of laser induced thermodynamically exothermic chemical reactions , second, investigating the physical principles that can be used to make laser sources capable of delivering high average powers. We note that, in order to reach both objectives, one has to convert electrical or chemical energy into laser energy, using dense gaseous media.. We present results from the early development of an F atom source appropriate for HF and DF chemical laser research. We next explain the very important difficulties encountered in working with dense gases for that purpose, and we shall describe how, especially at Evaluation of downstream-mixing scheme –levels transitions (001) → (100) and (001) → (020) gas dynamic laser The physical phenomena that control the operation of presently existing laser devices are now sufficiently well understood, so that it is possible to predict that new generations of lasers could be designed in the future. The proposed model of excitation and relaxation levels was finally proved by the computational numerical code of Matlab toolboxes of different parameters of nozzle.

Keywords: hydrogen, combust, chemical laser, halogen atom

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Authors: Nazlı Çetindağ, Pelin Yılmaz Çetiner, Metin Mert İlgün, Emine Birci, Gizemnur Yıldız Uysal, Özcan Hatipoğlu, Ehsan Tuzcuoğlu, Gökhan Sır

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Water scarcity is an unavoidable issue impacting an increasing number of individuals daily, representing a global crisis stemming from swift population growth, urbanization, and excessive resource exploitation. Consequently, solutions that involve the reclamation of wastewater are considered essential. In this context, household wastewater, categorized as greywater, plays a significant role in freshwater used for residential purposes and is attributed to washing. This type of wastewater comprises diverse elements, including organic substances, soaps, detergents, solvents, biological components, and inorganic elements such as certain metal ions and particles. The physical characteristics of wastewater vary depending on its source, whether commercial, domestic, or from a hospital setting. Consequently, the treatment strategy for this wastewater type necessitates comprehensive investigation and appropriate handling. The advanced oxidation process (AOP) emerges as a promising technique associated with the generation of reactive hydroxyl radicals highly effective in oxidizing organic pollutants. This method takes precedence over others like coagulation, flocculation, sedimentation, and filtration due to its avoidance of undesirable by-products. In the current study, the focus was on exploring the feasibility of the AOP for treating actual household wastewater. To achieve this, a laboratory-scale device was designed to effectively target the formed radicals toward organic pollutants, resulting in lower organic compounds in wastewater. Then, the number of microorganisms present in treated wastewater, in addition to the chemical content of the water, was analyzed to determine whether the lab-scale device eliminates microbial accumulation with AOP. This was also an important parameter since microbes can indirectly affect human health and machine hygiene. To do this, water samples were taken from treated and untreated conditions and then inoculated on general purpose agar to track down the total plate count. Analysis showed that AOP might be an option to treat household wastewater and lower microorganism growth.

Keywords: usage of household water, advanced oxidation process, water reuse, modelling

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Authors: Andrey V. Osipov, Sergey A. Kukushkin, Andrey V. Luk’yanov

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A method is developed for the solid-phase synthesis of epitaxial layers when the substrate itself is involved into a topochemical reaction and the reaction product grows in the interior of substrate layer. It opens up new possibilities for the relaxation of the elastic energy due to the attraction of point defects formed during the topochemical reaction in anisotropic media. The presented method of silicon carbide (SiC) formation employs a topochemical reaction between the single-crystalline silicon (Si) substrate and gaseous carbon monoxide (CO). The corresponding theory of interaction of point dilatation centers in anisotropic crystals is developed. It is eliminated that the most advantageous location of the point defects is the direction (111) in crystals with cubic symmetry. The single-crystal SiC films with the thickness up to 200 nm have been grown on Si (111) substrates owing to the topochemical reaction with CO. Grown high-quality single-crystal SiC films do not contain misfit dislocations despite the huge lattice mismatch value of ~20%. Also the possibility of growing of thick wide-gap semiconductor films on these templates SiC/Si(111) and, accordingly, its integration into Si electronics, is demonstrated. Finally, the ab initio theory of SiC formation due to the topochemical reaction has been developed.

Keywords: epitaxy, silicon carbide, topochemical reaction, wide-bandgap semiconductors

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Authors: R. Berrached, H. Ait Mahamed, A. Iddou

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Water pollution is nowadays a serious problem, due to the increasing scarcity of water and thus to the impact induced by such pollution on the human health. Various techniques are made use of to deal with water pollution. Among the most used ones, some can be enumerated: the bacterian bed, the activated mud, the Lagunage as biological processes and coagulation-floculation as a physic-chemical process. These processes are very expensive and an treatment efficiency which decreases along with the increase of the initial pollutants’ concentration. This is the reason why research has been reoriented towards the use of a process by adsorption as an alternative solution instead of the other traditional processes. In our study, we have tempted to exploit the characteristics of two metallic hydroxides Al and Fe to purify contaminated water by two industrial dyes SBL blue and SRL-150 orange. Results have shown the efficiency of the two materials on the blue SBL dye.

Keywords: metallic hydroxydes, industrial dyes, purificatıon,

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Authors: Juan C. Duran-Alvarez, Daniel Mejia, Rodolfo Zanella

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Heterogeneous photocatalysis is a promising method to achieve the complete degradation and mineralization of organic pollutants in water via their exhaustive oxidation. In order to take this advanced oxidation process towards sustainability, it is necessary to reduce the energy consumption, referred as the light sources and the post-treatment operations. For this, the synthesis of new nanostructures of low band gap semiconductors in the form of thin films is in continuous development. In this work, thin films of the low band gap semiconductor bismuth oxyiodide (BiOI) were synthesized via the Successive Ionic Layer Adsorption and Reaction (SILAR) method. For this, Bi(NO3)3 and KI solutions were prepared, and glass supports were immersed in each solution under strict rate and time immersion conditions. Synthesis was performed at room temperature and a washing step was set prior to each immersion. Thin films with an average thickness below 100 nm were obtained upon a cycle of 30 immersions, as determined by AFM and profilometry measurements. Cubic BiOI nanocrystals with average size of 17 nm and a high orientation to the 001 plane were observed by XRD. In order to optimize the synthesis method, several Bi/I ratios were tested, namely 1/1, 1/5, 1/10, 1/20 and 1/50. The highest crystallinity of the BiOI films was observed when the 1/5 ratio was used in the synthesis. Non-stoichiometric conditions also resulted in the highest uniformity of the thin layers. PVP was used as an additive to improve the adherence of the BiOI thin films to the support. The addition of 0.1 mg/mL of PVP during the washing step resulted in the highest adherence of the thin films. In photocatalysis tests, degradation rate of the antibiotic ciprofloxacin as high as 75% was achieved using visible light (380 to 700 nm) irradiation for 5 h in batch tests. Mineralization of the antibiotic was also observed, although in a lower extent; ~ 30% of the total organic carbon was removed upon 5 h of visible light irradiation. Some ciprofloxacin by-products were identified throughout the reaction; and some of these molecules displayed residual antibiotic activity. In conclusion, it is possible to obtain highly oriented BiOI thin films under ambient conditions via the SILAR method. Non-stoichiometric conditions using PVP additive are necessary to increase the crystallinity and adherence of the films, which are photocatalytically active to remove recalcitrant organic pollutants under visible light irradiation.

Keywords: bismuth oxyhalides, photocatalysis, thin films, water treatment

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Authors: Y. Landkocz, P. Gosset, A. Héliot, C. Corbière, C. Vendeville, V. Keravec, S. Billet, A. Verdin, C. Monteil, D. Préterre, J-P. Morin, F. Sichel, T. Douki, P. J. Martin

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Air Pollution produced by automobile traffic is one of the main sources of pollutants in urban atmosphere and is largely due to exhausts of the diesel engine powered vehicles. The International Agency for Research on Cancer, which is part of the World Health Organization, classified in 2012 diesel engine exhaust as carcinogenic to humans (Group 1), based on sufficient evidence that exposure is associated with an increased risk for lung cancer. Amongst the strategies aimed at limiting exhausts in order to take into consideration the health impact of automobile pollution, filtration of the emissions and use of biofuels are developed, but their toxicological impact is largely unknown. Diesel exhausts are indeed complex mixtures of toxic substances difficult to study from a toxicological point of view, due to both the necessary characterization of the pollutants, sampling difficulties, potential synergy between the compounds and the wide variety of biological effects. Here, we studied the potential indirect genotoxicity of emission of Diesel engines through on-line exposure of rats in inhalation chambers to a subchronic high but realistic dose. Following exposure to standard gasoil +/- rapeseed methyl ester either upstream or downstream of a particle filter or control treatment, rats have been sacrificed and their lungs collected. The following indirect genotoxic parameters have been measured: (i) telomerase activity and telomeres length associated with rTERT and rTERC gene expression by RT-qPCR on frozen lungs, (ii) γH2AX quantification, representing double-strand DNA breaks, by immunohistochemistry on formalin fixed-paraffin embedded (FFPE) lung samples. These preliminary results will be then associated with global cellular response analyzed by pan-genomic microarrays, monitoring of oxidative stress and the quantification of primary DNA lesions in order to identify biological markers associated with a potential pro-carcinogenic response of diesel or biodiesel, with or without filters, in a relevant system of in vivo exposition.

Keywords: diesel exhaust exposed rats, γH2AX, indirect genotoxicity, lung carcinogenicity, telomerase activity, telomeres length

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Authors: Piacentini Diego, Della Rovere Federica, Fattorini Laura, Lanni Francesca, Cittadini Martina, Altamura Maria Maddalena, Falasca Giuseppina

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Plants have evolved sophisticated mechanisms to cope with environmental cues. Changes in intracellular content and distribution of phytohormones, such as the auxin indole-3-acetic acid (IAA), have been involved in morphogenic adaptation to environmental stresses. In addition to phytohormones, plants can rely on a plethora of small signal molecules able to promptly sense and transduce the stress signals, resulting in morpho/physiological responses thanks also to their capacity to modulate the levels/distribution/reception of most hormones. Among these signaling molecules, nitrogen monoxide (nitric oxide – NO) is a critical component in several plant acclimation strategies to both biotic and abiotic stresses. Depending on its levels, NO increases plant adaptation by enhancing the enzymatic or non-enzymatic antioxidant systems or by acting as a direct scavenger of reactive oxygen/nitrogen (ROS/RNS) species produced during the stress. In addition, exogenous applications of NO-specific donor compounds showed the involvement of the signal molecule in auxin metabolism, transport, and signaling, under both physiological and stress conditions. However, the complex mechanisms underlying NO action in interacting with phytohormones, such as auxins, during metal stress responses are still poorly understood and need to be better investigated. Emphasis must be placed on the response of the root system since it is the first plant organ system to be exposed to metal soil pollution. The monocot Oryza sativa L. (rice) has been chosen given its importance as a stable food for some 4 billion people worldwide. In addition, increasing evidence has shown that rice is often grown in contaminated paddy soils with high levels of heavy metal cadmium (Cd) and metalloid arsenic (As). The facility through which these metals are taken up by rice roots and transported to the aerial organs up to the edible caryopses makes rice one of the most relevant sources of these pollutants for humans. This study aimed to evaluate if NO has a mitigatory activity in the roots of rice seedlings against Cd or As toxicity and to understand if this activity requires interactions with auxin. Our results show that exogenous treatments with the NO-donor SNP alleviate the stress induced by Cd, but not by As, in in-vitro-grown rice seedlings through increased intracellular root NO levels. The damages induced by the pollutants include root growth inhibition, root histological alterations and ROS (H2O2, O2●ˉ), and RNS (ONOOˉ) production. Also, SNP treatments mitigate both the root increase in root IAA levels and the IAA alteration in distribution monitored by the OsDR5::GUS system due to the toxic metal exposure. Notably, the SNP-induced mitigation of the IAA homeostasis altered by the pollutants does not involve changes in the expression of OsYUCCA1 and ASA2 IAA-biosynthetic genes. Taken together, the results highlight a mitigating role of NO in the rice root system, which is pollutant-specific, and involves the interaction of the signal molecule with both IAA and brassinosteroids at different (i.e., transport, levels, distribution) and multiple levels (i.e., transcriptional/post-translational levels). The research is supported by Progetti Ateneo Sapienza University of Rome, grant number: RG120172B773D1FF

Keywords: arsenic, auxin, cadmium, nitric oxide, rice, root system

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