Characterization of phosphogypsum wastes associated with phosphoric acid and fertilizers production

The present work is directed to characterize the phosphogypsum (PG) wastes associated with phosphoric acid produced by the wet process in industrial facility for the production of fertilizers and chemicals in Egypt. The PG waste samples were characterized in terms of spectroscopic analysis (X-ray diffraction, X-ray fluorescence, IR spectra) and radiometric analysis (γ- and α-measurements). The γ-ray measurements showed that the average activity concentrations are 140 ± 12.6, 459 ± 36.7, 323 ± 28.4, 8.3 ± 0.76 and 64.3 ± 4.1 Bq/kg for U-238, Ra-226, Pb-210, Th-232 and K-40, respectively. The α-particle measurements of uranium isotopes showed that the average activity concentrations of U-238, U-235 and U-234 were 153 ± 9.8, 7 ± 0.38, 152 ± 10.4 Bq/kg, respectively. The average radiochemical recovery (%) of the destructive α-particle measurements is ∼70% with a resolution (FWHM) of ∼30 keV. Activity ratios of U-238/Ra-226 and U-238/Pb-210 were less than unity (i.e., <1) and equal to 0.31 ± 0.02 and 0.47 ± 0.16, respectively. The isotopic ratios of U-238/U-235 and U-238/U-234 (in PG and PR samples) were close to the normal values of ∼21.7 and ∼1, respectively and are not affected by the wet processing of phosphate rock (PR). The obtained results of PG waste samples were compared with phosphate rock (PR) samples. The radiation hazard indices are namely, radium activity index (Ra-Eq > 370 Bq/kg), total absorbed gamma dose rate (D_γr > 5 nGy/h) and radon emanation fraction (Rn-EF > 20%). Uncertainty of the sample counting was 95% confidence level of σ. The results indicated the necessity to find suitable routes to decrease and/or redistribute the radionuclide of environmental interest (i.e., Ra-226) in PG wastes, consequently to reduce its radiation impacts in the surrounding environment.     

Radiological impacts of natural radioactivity in Abu-Tartor phosphate deposits, Egypt.

Phosphate and environmental samples were collected from Abu Tartor phosphate mine and the surrounding region. The activity concentration of 226Ra (238U) series, 232Th series and 40K were measured using a gamma-ray spectrometer. The activities of uranium isotopes (238U, 235U and 234U) and 210Pb were measured using an alpha spectrometer and a low-background proportional gas counting system, respectively, after radiochemical separation. The results are discussed and compared with the levels in phosphate rocks from different countries. It seems that the Abu Tartor phosphate deposit has the lowest radioactivity level of exploited phosphate of sedimentary origin. 226Ra/238U, 210Pb/226Ra, 234U/238U and 226Ra/228Ra activity ratios were calculated and are discussed. The radioactivity levels in the surrounding region and the calculated exposure dose (nGy/h) will be considered as a pre-operational baseline to estimate the possible radiological impacts due to mining, processing and future phosphate industrial activities. To minimize these impacts, the processing wastes should be recycled to the greatest possible extent.     

Measurement of natural radioactivity in building materials in Qena city, Upper Egypt

Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials (bricks, cement, gypsum, ceramics, marble, limestone and granite) in Qena city, Upper Egypt have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. The results show that the highest mean value of (226)Ra activity is 205+/-83 Bqkg(-1) measured in marble. The corresponding value of (232)Th is 118+/-14 Bqkg(-1) measured in granite. For (40)K this value is (8.7+/-3.9)x10(2) Bqkg(-1) measured in marble. The average concentrations of the three radionuclides in the different building materials are 116+/-54, 64+/-34 and (4.8+/-2.2)x10(2) Bqkg(-1) for (226)Ra, (232)Th and (40)K, respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The maximum mean of radium equivalent activity Ra(eq) is 436+/-199 Bqkg(-1) calculated in marble. The highest radioactivity level and dose rate in air from these materials were calculated in marble.     

Chemical characterization of naturally weathered oil residues in arid terrestrial environment in Al-Alamein, Egypt.

The main objective of this study was to investigate compositional changes in a range of source- and weathering-dependent molecular parameters in oil residues in the arid terrestrial environment of Al-Alamein, Egypt. The results of aromatic hydrocarbon analysis demonstrated the stability of several aromatic hydrocarbon ratios in oil residues over a wide range of weathering and hydrocarbon concentrations. The ratios of C2-dibenzothiophenes/C2-phenanthrenes (C2-DBTs/C2-PHENs), C3-dibenzothiophenes/C3-phenanthrenes (C3-DBTs/C3-PHENs), C2-chrysenes/C1-chrysenes (C2-CHRYs/C1-CHRYs), and C2-dibenzothiophenes/C1-dibenzothiophenes (C2-DBTs/C1-DBTs) were nearly constant in oil residues of varying degrees of weathering. Biomarker ratios of hopanes and steranes were useful for source identification even for severely weathered oil residues. The data confirmed previous observations that C29 20S/(20S + 20R) and C29 betabeta/(betabeta+ alphaalpha) sterane epimer ratios, and C29/C30, C30 alphabeta(alphabeta + 3alpha), C31 22S/(22S + 22R) hopane ratios correlate well even after extensive weathering of spilled oils, although some exceptions were encountered for an extensively weathered surface sample. The data provided clear evidence of correlation between samples of the weathered oil residues and the possible source oil. Moreover, the results of biomarker compositions were in good agreement with weathering classification based on alkanes and aromatic hydrocarbons. In general, samples with lowest pregnane indices (PI) and tricyclic terpane indices (TriTI) showed the lowest concentrations of n-alkanes and alkylated polycyclic aromatic hydrocarbon (PAH) homologues, the highest weathering ratios (WRs), the highest values of unresolved complex mixture (UCM)/total resolved peak (TRP) ratios, and the highest ratios of C2 and C3-alkylated CHRYs to their counterparts in the PHEN and DBT series.     

“一带一路”国家天然气投资绩效评价及其改进路径

运用超效率数据包络分析(SE-DEA)方法,综合考虑目标国资源现状、政治因素、经济技术、社会条件、市场体制和国际合作情况,构建天然气投资绩效评价线性规划模型,并以2003—2013年中国对"一带一路"国家的天然气投资绩效均值进行聚类,结合规模报酬和投入要素的影子价格分析,提出目标国天然气投资绩效改进路径。结果显示:(1)中国对中亚及北亚、东南亚和南亚的天然气投资普遍处于中高效区,对独联体、中东欧洲和西亚北非地区的天然气投资普遍处于中低效区。(2)高效区国家自2012年起投资绩效处于规模报酬不变阶段,技术水平和国家经济对天然气贸易的依赖程度是影响投资绩效的关键因素。(3)中效区国家投资绩效大多处于规模报酬递增阶段,从2013年起总储量、人文地理和与中国油气合作状况成为影响中效区投资绩效的关键因素。(4)低效区国家投资绩效处于规模报酬递增阶段,国家经济对天然气贸易的依赖程度和技术水平要素是影响低效区投资绩效的关键因素;此外,对于处于低效区的中亚国家资源现状是影响投资绩效的另一关键因素,政治因素则是中东欧洲和独联体国家的关键因素,东南亚和南亚地区的投资关键因素则包含社会条件。这意味着,中国要提高在"一带一路"区域的天然气投资绩效,就要针对不同地区投资现状制定改进策略。对于高效区和低效区的中亚国家,未来中国要加强同目标国政府间的沟通,达成"以技术换气条款";对中效区和低效区的中东欧洲、独联体国家可采用与油气企业合作方式降低合作风险;对低效区的东南亚和南亚国家,可签订天然气长期贸易合同。     

Distribution of natural radionuclides in the production and use of phosphate fertilizers in Brazil

The Brazilian phosphate fertilizer is obtained by wet reaction of igneous phosphate rock with concentrated sulphuric acid, giving as final product, phosphoric acid and dehydrated calcium sulphate (phosphogypsum) as by-products. Phosphoric acid is the starting material for triple superphosphate (TSP), single superphosphate (SSP), monoammonium phosphate (MAP) and diammonium phosphate (DAP). The phosphate rock used as raw material presents in its composition radionuclides of the U and Th natural series. Taking this into account, the main aim of this paper is to evaluate the fluxes of natural radionuclides and radioactive disequilibria involved in the Brazilian industrial process of phosphoric acid production; to determine the content of radioactivity in several commercial fertilizers produced by this industry; to estimate their radiological impact in crop soils and the long term exposure due to their application. Radiological characterization of phosphate rock, phosphogypsum and phosphate fertilizers was performed by alpha and gamma spectrometry. The fertilizer samples, which are derived directly from phosphoric acid, MAP and DAP, presented in their composition low activity concentrations for 226Ra, 228Ra and 210Pb. As for U and Th, the concentrations found in MAP and DAP are more significant, up to 822 and 850Bqkg(-1), respectively. SSP and TSP, which are obtained by mixing phosphoric acid with different amounts of phosphate rock, presented higher concentrations of radionuclides, up to 1158Bqkg(-1) for (238)U, 1167Bqkg(-1) for (234)U, 1169Bqkg(-1) for 230Th, 879Bqkg(-1) for 226Ra, 1255Bqkg(-1) for 210Pb, 521Bqkg(-1) for 232Th, 246Bqkg(-1) for 228Ra and 302Bqkg(-1) for 228Th. Long term exposure due to successive fertilizer applications was evaluated. Internal doses due to the application of phosphate fertilizer for 10, 50 and 100 years were below 1mSvy(-1), showing that the radiological impact of such practice is negligible.     

Towards integrating production and consumption to reduce consumer food waste in developed countries

Abstract

Literature analysing reasons for Consumer Food Waste (CFW) revealed that it cannot be reduced to consumer behaviour alone. In fact, CFW should not be conceptualised as the problem but as a symptom of a food system that oversupplies and encourages consumerism. This research focuses on preventing CFW in the United Kingdom (UK), as a representative of a developed country, by improving the traditional food provisioning system to better integrate production and consumption. To achieve this, five stages are identified to design a sustainable product service system (PSS) capable of supporting consumers to better manage their food operations: (1) strategic analysis of current food provisioning system, (2) exploring system level innovations leading to minimisation of CFW, (3) refinement and selection of PSS, (4) designing the most promising PSS from an environmental, economic and social perspective, and (5) evaluating designed PSS. This paper considers the first of these stages, reviews reasons for and existing solutions to CFW, and provides a strategic analysis of the current food provisioning system to identify characteristics that could be exploited within a new PSS. Initial investigations reveal applicability of PSS concept to the food provisioning system and potential for reduction of CFW if core causes are addressed.     

(210)Pb content in natural gas pipeline residues ("black-powder") and its correlation with the chemical composition

The present work was carried out to assess the (210)Pb content in "black-powder" found in pigging operations on gas pipelines in Brazil, in particular, on the Campos Basin gas pipeline. Additionally, the chemical composition of such deposits was determined and an eventual correlation with (210)Pb concentration evaluated. Typical "black-powder" generated in the natural gas pipeline from Campos Basin oilfield contains mainly iron oxide ( approximately 81%) and residual organic matter ( approximately 9%). The (210)Pb content ranges from 4.9 to 0.04k Bqkg(-1) and seems to be inversely correlated with the distance to the platforms. On the other hand, (226)Ra concentration is higher on the pipeline branch between the platform and the onshore installations. (228)Ra was only observed in few samples, in particular, in the samples with the highest (226)Ra content.     

The hydrogeochemistry of the Pleistocene aquifer in the Nile Delta area,Egypt

The Pleistocene aquifer represents the main aquifer underlying the Nile Delta area. This aquifer is directly affected by the surface water from the Nile branches. However, the study of the hydrogeochemistry of this aquifer indicates the possibility of classifying it into three hydrochemical zones from south to north. The groundwater chemistry of each zone is the resultant effect of the local factors controlling the development of groundwater quality.     

Estimation of the impact of oil palm plantation establishment on greenhouse gas balance

Estimates of emissions indicate that if tropical grassland is rehabilitated by oil palm plantations, carbon fixation in plantation biomass and soil organic matter not only neutralises emissions caused by grassland conversion, but also results in the net removal of about 135 Mg carbon dioxide per hectare from the atmosphere. In contrast, the emission from forest conversion clearly exceeds the potential carbon fixation of oil palm plantings. Forest conversion on mineral soils to promote continued oil palm mono cropping causes a net release of approximately 650 Mg carbon dioxide equivalents per hectare, while the emission from peat forest conversion is even higher due to the decomposition of drained peat and the resulting emission of carbon oxide and nitrous oxide. The conversion of one hectare of forest on peat releases over 1,300 Mg carbon dioxide equivalents during the first 25-year cycle of oil palm growth. Depending on the peat depth, continuous decomposition augments the emission with each additional cycle at a magnitude of 800 Mg carbon dioxide equivalents per hectare. The creation of ‘flexibility mechanisms’ such as the clean development mechanism and emission trading in the Kyoto Protocol could incorporate plantations as carbon sinks in the effort to meet emission targets. Thus, for the oil palm industry, grassland rehabilitation is an option to preserve natural forest, avoid emissions and, if the sequestered carbon becomes tradable, an opportunity to generate additional revenue. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.     

Composition of soil diatoms in zones of impact from oil production complexes

The impact of territorial oil production complexes on the species composition of soil diatom (Bacillariophyta) communities and the degree of their development has been studied. On the basis of comparisons between dominant diatom assemblages from different natural zones, suggestions are made concerning the strategy of their adaptation to extreme environmental conditions. A scheme of transformation of diatom communities under the impact of oil pollution is proposed.     

Spatial distribution of U isotopes in sea-water sediments, Red Sea, Egypt

Isotopes of uranium in the sea-water sediments collected from two different areas (El Hamraween harbour and Ras El Behar) on the Egyptian coast of the red sea have been studied using radiochemical separation procedures and alpha-particle spectrometry. Activity concentrations of ²³⁸U, ²³⁵U, ²³⁴U were calculated. The activities observed indicated enhanced radioactivity levels in sea-water sediments of El Hamraween harbour area due to the activities of phosphate shipment operation. Secular equilibrium between ²³⁴U and ²³⁸U was found in the analyzed samples. The average activity ratio of ²³⁵U/²³⁸U was close to the value 0.046 for uranium in nature.     

Closed-loop supply chain system with energy,transportation and waste disposal costs

Energy usage and consumption play important and strategic roles in modern manufacturing, inventory and logistics systems. The literature on inventory models for closed-loop supply chains reveals that, for no clear reasons, energy costs were ignored along with transportation and disposal costs. This paper introduces a closed-loop supply chain model that considers the economic value and energy content of products. It also offers a novel framework for studying lot-sizing policies of production processes in that context. Thus, a mathematical model for a closed-loop supply chain system with energy, transportation and disposal costs is developed. Numerical examples are provided with their results discussed. The developed model was also compared to that of Richter (1996) to stress the importance of accounting for the three noted costs. The numerical results emphasise that accounting for energy, transportation and disposal costs in supply chain modelling increases the sustainability of a production-inventory system due to the strong interdependence of the three costs on one hand, and their relationship to the environment on the other hand.     

Soil radium, soil gas radon and indoor radon empirical relationships to assist in post-closure impact assessment related to near-surface radioactive waste disposal

Least squares (LS), Theil’s (TS) and weighted total least squares (WTLS) regression analysis methods are used to develop empirical relationships between radium in the ground, radon in soil and radon in dwellings to assist in the post-closure assessment of indoor radon related to near-surface radioactive waste disposal at the Low Level Waste Repository in England. The data sets used are (i) estimated ²²⁶Ra in the <2 mm fraction of topsoils (eRa226) derived from equivalent uranium (eU) from airborne gamma spectrometry data, (ii) eRa226 derived from measurements of uranium in soil geochemical samples, (iii) soil gas radon and (iv) indoor radon data. For models comparing indoor radon and (i) eRa226 derived from airborne eU data and (ii) soil gas radon data, some of the geological groupings have significant slopes. For these groupings there is reasonable agreement in slope and intercept between the three regression analysis methods (LS, TS and WTLS). Relationships between radon in dwellings and radium in the ground or radon in soil differ depending on the characteristics of the underlying geological units, with more permeable units having steeper slopes and higher indoor radon concentrations for a given radium or soil gas radon concentration in the ground. The regression models comparing indoor radon with soil gas radon have intercepts close to 5 Bq m⁻³ whilst the intercepts for those comparing indoor radon with eRa226 from airborne eU vary from about 20 Bq m⁻³ for a moderately permeable geological unit to about 40 Bq m⁻³ for highly permeable limestone, implying unrealistically high contributions to indoor radon from sources other than the ground. An intercept value of 5 Bq m⁻³ is assumed as an appropriate mean value for the UK for sources of indoor radon other than radon from the ground, based on examination of UK data. Comparison with published data used to derive an average indoor radon: soil ²²⁶Ra ratio shows that whereas the published data are generally clustered with no obvious correlation, the data from this study have substantially different relationships depending largely on the permeability of the underlying geology. Models for the relatively impermeable geological units plot parallel to the average indoor radon: soil ²²⁶Ra model but with lower indoor radon: soil ²²⁶Ra ratios, whilst the models for the permeable geological units plot parallel to the average indoor radon: soil ²²⁶Ra model but with higher than average indoor radon: soil ²²⁶Ra ratios.     

Hazardous waste, impact on health and environment for development of better waste management strategies in future in India

Industry has become an essential part of modern society, and waste production is an inevitable outcome of the developmental activities. A material becomes waste when it is discarded without expecting to be compensated for its inherent value. These wastes may pose a potential hazard to the human health or the environment (soil, air, water) when improperly treated, stored, transported or disposed off or managed. Currently in India even though hazardous wastes, emanations and effluents are regulated, solid wastes often are disposed off indiscriminately posing health and environmental risk. In view of this, management of hazardous wastes including their disposal in environment friendly and economically viable way is very important and therefore suggestions are made for developing better strategies. Out of the various categories of the wastes, solid waste contributes a major share towards environmental degradation. The present paper outlines the nature of the wastes, waste generating industries, waste characterization, health and environmental implications of wastes management practices, steps towards planning, design and development of models for effective hazardous waste management, treatment, approaches and regulations for disposal of hazardous waste. Appraisal of the whole situation with reference to Indian scenario is attempted so that a better cost-effective strategies for waste management be evolved in future.     

Road energy consumption,economic growth,population and urbanization in Egypt: cointegration and causality analysis

The study investigates the causal relationships between road energy consumption, economic growth, urbanization and population growth in Egypt over the period (1980–2011). I use Johansen cointegration approach, vector error correction model (VECM), generalized impulse response functions and variance decomposition technique. The results show the existence of long-run relationship between the variables. Moreover, the results indicate the existence of unidirectional long-run causality running from road energy consumption to urbanization and from road energy consumption to economic growth which implies the existence of growth hypothesis in the long run. Also, there is bidirectional short-run causality between road energy consumption and economic growth, which indicates the existence of feedback hypothesis in the short run. These results imply that road energy consumption determines economic growth in the both short run and long run and economic growth causes road energy consumption in the short run. And according to these results, several policy implications will be suggested for policymakers. They should take into consideration while implementing energy conservation policies, the possible negative effect on economic growth and have to concentrate on technological development policies and to make a shift towards using clean alternative fuel as natural gas and focus on investment in renewable energy resources.     

Assessment of plastic lumber production in Brazil as a substitute for natural wood

Environment, Development and Sustainability - This review aimed to analyze plastic lumber manufacturing in Brazil, a country with a large amount of natural wood, and devise strategies to boost...