Climatic changes and their role in emergence and re-emergence of diseases

Environmental Science and Pollution Research - Global warming and the associated climate changes are predictable. They are enhanced by burning of fossil fuels and the emission of huge amounts of...     

The efficacy of an oxidation pond in mineralizing some industrial waste products with special reference to fluorene degradation: a case study

The efficacy of the oxidation pond on the outskirts of the 10th of Ramadan, the main industrial city, in Egypt was examined. Samples of wastewater collected from the inlet and the outlet were screened for some priority pollutants. Acenaphthene and fluorene were the most frequently detected polycyclic aromatic hydrocarbons, while dimethyl phthalate was the most frequently detected phthalate ester. The spectrum of pollutants, their concentrations and frequencies were similar in the inlet and the outlet, indicating an inferior mineralization capability of the pond. Several degradative bacterial strains were isolated from the pond and grown on M56 minimal media supplemented with different pollutants as the carbon source. The efficacy of pure and mixed cultures to break down fluorene, the most frequently detected pollutant was examined. Fluorene degradation was fast in the first 10 days, then followed by a slow phase. Mixed culture had a higher rate of fluorene degradation in comparison to pure cultures. High performance liquid chromatography analysis of fluorene degradation showed three degradative metabolites. But GC/MS analysis detected one compound, identified as acetamide. The present work has indicated the poor efficacy of the pond. Lack of primary treatment of industrial effluent at factory level, coupled with shock loads of toxicants that may damage the microorganisms and their degradative capabilities are presumably main factors behind such inferior performance. Moreover, the type of pollutants discharged into the pond tend to fluctuate and change depending on the rate from the factories discharge and work shifts. Such irregular feeding of persistent pollutants may have led to a wash out of specialized strains of bacteria capable to degrade such persistent pollutants.     

Energy and environmental applications of carbon nanotubes

Energy and environment are major global issues inducing environmental pollution problems. Energy generation from conventional fossil fuels has been identified as the main culprit of environmental quality degradation and environmental pollution. In order to address these issues, nanotechnology plays an essential role in revolutionizing the device applications for energy conversion and storage, environmental monitoring, as well as green engineering of environmental friendly materials. Carbon nanotubes and their hybrid nanocomposites have received immense research attention for their potential applications in various fields due to their unique structural, electronic and mechanical properties. Here, we review the applications of carbon nanotubes (1) in energy conversion and storage such as in solar cells, fuel cells, hydrogen storage, lithium ion batteries and electrochemical supercapacitors, (2) in environmental monitoring and wastewater treatment for the detection and removal of gas pollutants, pathogens, dyes, heavy metals and pesticides and (3) in green nanocomposite design. Integration of carbon nanotubes in solar and fuel cells has increased the energy conversion efficiency of these energy conversion applications, which serve as the future sustainable energy sources. Carbon nanotubes doped with metal hydrides show high hydrogen storage capacity of around 6?wt% as a potential hydrogen storage medium. Carbon nanotubes nanocomposites have exhibited high energy capacity in lithium ion batteries and high specific capacitance in electrochemical supercapacitors, in addition to excellent cycle stability. High sensitivity and selectivity towards the detection of environmental pollutants are demonstrated by carbon nanotubes based sensors, as well as the anticipated potentials of carbon nanotubes as adsorbent to remove environmental pollutants, which show high adsorption capacity and good regeneration capability. Carbon nanotubes are employed as reinforcement material in green nanocomposites, which is advantageous in supplying the desired properties, in addition to the biodegradability. This article presents an overview of the advantages imparted by carbon nanotubes in electrochemical devices of energy applications and green nanocomposites, as well as nanosensor and adsorbent for environmental protection.     

Adaptive cluster sampling with clusters selected without replacement and stopping rule

Adaptive cluster sampling (ACS) has received much attention in recent years since it yields more precise estimates than conventional sampling designs when applied to rare and clustered populations. These results, however, are impacted by the availability of some prior knowledge about the spatial distribution and the absolute abundance of the population under study. This prior information helps the researcher to select a suitable critical value that triggers the adaptive search, the neighborhood definition and the initial sample size. A bad setting of the ACS design would worsen the performance of the adaptive estimators. In particular, one of the greatest weaknesses in ACS is the inability to control the final sampling effort if, for example, the critical value is set too low. To overcome this drawback one can introduce ACS with clusters selected without replacement where one can fix in advance the number of distinct clusters to be selected or ACS with a stopping rule which stops the adaptive sampling when a predetermined sample size limit is reached or when a given stopping rule is verified. However, the stopping rule breaks down the theoretical basis for the unbiasedness of the ACS estimators introducing an unknown amount of bias in the estimates. The current study improves the performance of ACS when applied to patchy and clustered but not rare populations and/or less clustered populations. This is done by combining the stopping rule with ACS without replacement of clusters so as to further limit the sampling effort in form of traveling expenses by avoiding repeat observations and by reducing the final sample size. The performance of the proposed design is investigated using simulated and real data.     

Effect of dye auxiliaries on chemical oxygen demand and colour competitive removal from textile effluents using Posidonia oceanica

The use of an abundant and widely distributed seagrass species, Posidonia oceanica, as a biosorbent for the direct dye Yellow 44 was successfully shown. The studies were performed on the single dyestuff dissolved in water and in a dyebath containing agents commonly used in the textile industry, i.e. a surfactant (Lavotan TBU), a sequestring agent (Meropan DPE), a softening agent (Eurosoft CI10) and a salt (NaCl). The colour reduction results showed that P. oceanica was found to be more efficient for removal of Yellow 44 from an aqueous solution (162 mg g^?1) than from a dyebath solution (135 mg g^?1), according to the Langmuir isotherm model. For the single dyestuff sorption, Fourier transform infrared and X-ray photoelectron spectroscopy studies highlighted chemical sorption between the dye alcohol function and the sorbent acid function. The chemical oxygen demand removal percentages were found to be 54.9 and 76.6% for Yellow 44 dissolved in aqueous solution and in dyebath solution, respectively. This confirmed the both sorption of the chemical auxiliaries and the dye on P. oceanica.     

Chromium geochemistry in coastal environment of the Western Harbour,Egypt: water column,suspended matter and sediments

The distribution of Cr between water, total suspended matter (TSM) and sediments in the maine harbour in Egypt (Western Harbour), has been studied in two surveys. Dissolved Cr displayed a negative association with salinity, indicating land sources outlets as a major source of inputs for it. The Harbour presents higher Cr concentrations in dissolved form above the background (0.17 μg/L) concentration for total dissolved Cr. The most important factors controlling the distribution of particulate Cr in the Western Harbour are the depositional from several activities inside the Harbour, as well as different charges from several landbased sources along its southern edge. Chromium was associated in decreasing amount in the: residual >oxidizable-organic >acid reducible >exchangeable fractions of the analyzed sediments. Therefore, the results indicate that Cr in sediments from W.H is not available for exchange and/or release into the marine environment.     

Polycyclic aromatic hydrocarbon derivatives in airborne particulate matter: sources,analysis and toxicity

Polycyclic aromatic hydrocarbons (PAHs) are worldwide pollutants produced mainly during incomplete combustion and pyrolysis of organic substances. PAH derivatives are components with hydrogen on the aromatic ring substituted by carbonyl-, nitro- and hydroxyl-functional groups (N-PAH, O-PAH or OH-PAH), or a group of heterocyclic PAHs containing one sulfur atom in place of a carbon atom in the aromatic ring. PAHs and their derivatives can be either introduced in the atmosphere directly in this form as primary pollutants, or formed by homogenous and heterogeneous oxidation reactions. During the last decades, interest on studying PAH derivatives has increased because derivatives may be more harmful than parent compounds. PAH derivatives have been detected in the atmospheric particulate matter in numerous cities worldwide. PAH derivatives enter living organisms by inhalation, oral ingestion and dermal contact. In vivo and in vitro experiments together with epidemiological studies have shown the toxic effects of PAH derivatives, notably for compounds present in airborne and diesel exhaust particles. Here we review the sources, the mechanisms of formation, the physicochemical properties, the analytical methods, and the toxicological effects of PAHs and their derivatives in airborne particulate matter.     

Game theory and hybrid genetic algorithm for energy management and real-time pricing in smart grid: the Tunisian case

ABSTRACT

Microgrids are the key for integrating renewable energy from different sources into smart grid, that is why power grid evolves into a combination of interconnected microgrids. In fact, future power grids are undergoing this groundbreaking change that will help meet the increasing demand of electric power and reduce carbon emission. In this sense we study in this paper, based on measured data, a real case of energy management in the area of Beja located in Tunisia. Indeed, we propose a model for the power exchange which proves the potential of applying game theory in the development of both real-time pricing and energy management mechanism for an open electricity market. We also introduce a hybrid genetic algorithm to compute the Nash Equilibrium. Results show that the proposed smart energy management can decrease the real cost of power up to 20%, to divide the energy transmission losses by a factor of two and to reduce the carbon emission in the area of Beja.     

Bioconversion of sugarcane bagasse into a protein-rich product by white rot fungus

The fungus Pleurotus ostreatus NRRL-2366 degraded 56.7% and 45.9% of untreated and chemically pretreated (delignified) sugarcane bagasse, respectively, during 14-day incubation in a submerged fermentation process. The biodegradation percentages of cellulose, hemicellulose and lignin were 33.0%, 72.5% and 14.5%, respectively. An increment of 22.6% of crude protein content in the residual fermented material was observed. Chemical composition of the end-product and its amino acids profile were reported.