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Результаты 321-330 из 741
Implementation of the selective collection in small villages of less than 50 inhabitants in Cantabria region (Spain): Preliminary viability study
2010
Margallo Blanco, María | Aldaco García, Rubén | Bala Gala, Alba | Fullana i Palmer, Pere | Irabien Gulías, Ángel | Universidad de Cantabria
This project develops an algorithm for allowing municipalities of dispersed villages of Cantabria, an Autonomous Community situated in the north coast of Spain, to check the environmental feasibility of extending the selective collection in their municipalities. The algorithm will allow these municipalities to introduce their own data and compare two waste management systems (Scenario A and B). Scenario A is referred to the current waste management system in which no selective collection is being carried out. Consequently, light packaging material (LP) and paper and cardboard (P/C) are collected together with the municipal solid wastes (MSW), following the same path. Scenario B is the hypothetic new waste management system in which selective collection is introduced. To determine the environmental preference of these scenarios, an algorithm based on Life Cycle Assessment (LCA) has been developed. Only if environmental impacts in Scenario B are lower than in A when running the model the extension of the selective collection for each individual municipality should be recommended.
Показать больше [+] Меньше [-]Impact analysis of the Spanish electric energy market liberalization on Chlor-alkali industry
2010
Aldaco García, Rubén | Onandía de Dios, Raquel | Irabien Gulías, Ángel | Universidad de Cantabria
A sodium chloride solution is decomposed electrolytically to generate gaseous chlorine, sodium hydroxide and hydrogen. Electricity accounts for about 50 % of total production cost. In Spain, the Electrical Sector Act 54/1997 commenced the electric market liberalization, with the introduction into national laws the provisions contained in European Directive 96/92/EC. In July 2008, tariffs disappear for industry consumers. Hourly discrimination complement, given by tariffs, it has been an important energy costs optimization way for chlor-alkali industry and now it is not so evident the modulation advantage. This article tries to analyze impacts in chlor-alkali industry of this new electric markett.
Показать больше [+] Меньше [-]Photovoltaic Solar Electrochemical Oxidation (PSEO) for lignosulfonate waste water treatment
2010
Domínguez Ramos, Antonio | Aldaco García, Rubén | Irabien Gulías, Ángel | Universidad de Cantabria
Under the current global energy scenario, the need of self-sustainable processes is encouraged. A process of Photovoltaic Solar powered Electrochemical Oxidation (PSEO) has been developed to remove the organic matter from lignosulfonate waste water. Experimental results show that the process is able to oxidize the organic matter up to removal yields around 90% of Total Organic Carbon (TOC) under the described operating conditions, demonstrating the technical suitability of the PSEO process.
Показать больше [+] Меньше [-]Regulated metal levels in particulate matter in the Cantabria region (Northern Spain) using multivariate linear regression (MLR)
2010
Arruti Fernández, Axel | Fernández Olmo, Ignacio | Irabien Gulías, Ángel | Universidad de Cantabria
The levels and chemical composition of the particulate matter (PM) are linked to the effects of this atmospheric pollutant on human health. An assessment of the PM levels and its constituents present in the atmosphere is an important requirement of the air quality management and air pollution abatement. Taking into account that (i) EC Directives allow the Regional Government to assess the air quality by objective estimation and modelling techniques and (ii) the experimental effort required in the analysis of heavy metals in air, the present work aims to estimate the annual levels of the heavy metals regulated by the EC Directives (Pb in 1999/30/EC, and As, Ni and Cd in 2004/107/EC) in PM10 by means of multivariate linear regression (MLR). The main results show that although important deviations are found for individual measurements, the 2008 annual average metal concentrations are well estimated by the MLR technique at the studied areas. So, these estimations may be used by Regional Governments for the level assessment of regulated metals when their concentrations are below the lower assessment threshold | The authors would like to thank the Spanish Ministry of Education and Science (CTM2006-00317) and the Government of Cantabria (“Actions for improving the air quality and its diagnosis in Cantabria”) for their funding.
Показать больше [+] Меньше [-]Impact of Long-Term Application of Fertilizers on N₂O and NO Production Potential in an Intensively Cultivated Sandy Loam Soil
2010
Ding, Weixin | Yagi, Kazuyuki | Cai, Zucong | Han, Fengxiang
Literature reports on N₂O and NO emissions from organic and mineral agricultural soil amended with N-containing fertilizers have reached contradictory conclusions. To understand the influence of organic manure (OM) and chemical fertilizer application on N₂O and NO emissions, we conducted laboratory incubation experiments on an agricultural sandy loam soil exposed to different long-term fertilization practices. The fertilizer treatments were initiated in 1989 at the Fengqiu State Key Agro-ecological Experimental Station and included a control without fertilizer (CK), OM, mineral NPK fertilizer (NPK), mineral NP fertilizer (NP), and mineral NK fertilizer (NK). The proportion of N emitted as NO and N₂O varied considerably among fertilizer treatments, ranging from 0.83% to 2.50% as NO and from 0.08% to 0.36% as N₂O. Cumulative NO emission was highest in the CK treatment after NH ₄ ⁺ -N was added at a rate of 200 mg N kg⁻¹ soil during the 612-h incubation period, whereas the long-term application of fertilizers significantly reduced NO emission by 54-67%. In contrast, the long-term application of NPK fertilizer and OM significantly enhanced N₂O emission by 95.6% and 253%, respectively, compared to CK conditions. The addition of NP fertilizer (no K) significantly reduced N₂O emission by 25.5%, whereas applications of NK fertilizer (no P) had no effect. The difference among the N-fertilized treatments was due probably to discrepancies in the N₂O production potential of the dominant ammonia-oxidizing bacteria (AOB) species rather than AOB abundance. The ratio of NO/N₂O was approximately 24 in the CK treatment, significantly higher than those in the N-fertilized treatments (3-11), and it decreased with increasing N₂O production potential in N-fertilized treatments. Our data suggests that the shift in the dominant AOB species might produce reciprocal change in cumulative NO and N₂O emissions.
Показать больше [+] Меньше [-]Difference in the Use of a Quartz Filter and a PTFE Filter as First-Stage Filter in the Four-Stage Filter-Pack Method
2010
Aikawa, Masahide | Hiraki, Takatoshi
We evaluated the differences in the use of a quartz filter and a polytetrafluoroethylene (PTFE) filter as a first (F0)-stage filter in a four-stage filter-pack method. A four-stage filter-pack method can completely collect sulfur species (SO₂ and SO ₄ ²⁻ ), nitrate species (HNO₃ and NO ₃ ⁻ ), and ammonium species (NH₃ and NH ₄ ⁺ ) with little or no leakage irrespectively of the first-stage filter used. On the other hand, a seasonal variation was observed in the efficiency of collection between the quartz filter and the PTFE filter depending on the material to be collected. There was no seasonal variation in the efficiency of collection in sulfur species; in contrast, a clear seasonal variation was observed for the nitrate and ammonium species. As for NO ₃ ⁻ , the PTFE filter was more vulnerable than the quartz filter at air temperatures below 21°C, while the quartz filter was more vulnerable than the PTFE filter at air temperatures exceeding 21°C. A similar vulnerability for air temperature was observed for NH ₄ ⁺ , although the threshold air temperature was 23°C for NH ₄ ⁺ . Consequently, the evaporation loss of NO ₃ ⁻ would be mainly attributable to the volatilization of NH₄NO₃, although it is also partially due to the volatilization of NH₄Cl.
Показать больше [+] Меньше [-]Engineering Aspects of Electrochemical Generation of Ferrate: A Step Towards Its Full Scale Application for Water and Wastewater Treatment
2010
Alsheyab, Mohammad | Jiang, Jia-Qian | Stanford, Cécile
The objective of this paper is to design a pilot plant electrochemical reactor and to prove the operational concept of the electrochemical production of ferrate in situ and its online application for sewage treatment. To that end, the first part of this paper focuses on the analysis of the main engineering aspects of the reactor and the electrochemical process that affect the ferrate production, using laboratory scale experiments such as the interelectrode gap, the space-time yield, the area/volume (A/V) ratio, the current efficiency, and the energy consumption. The second part focuses on the production of ferrate using a pilot plant scale to prove the operational concept of the electrochemical generation of ferrate in situ and its online application as a step towards its full scale application for water and wastewater treatment.
Показать больше [+] Меньше [-]Evaluation of Physicochemical Methods for Treatment of Cu, Pb, Sb, and Zn in Canadian Small Arm Firing Ranges Backstop Soils
2010
Laporte-Saumure, Mathieu | Martel, Richard | Mercier, Guy
This paper presents the results of physicochemical treatment on Pb-, Cu-, Sb-, and Zn-contaminated Canadian small arm firing range (SAFR) backstop soils in order to evaluate the potential of such methods for remediation of SAFR backstop soils. Remediation target for the treatment assays was to attain the Québec Department of Environment commercial C criterion or more realistically, to reach the soil burial D criterion. Two treatment lines (TL) were evaluated. TL-1, consisting of jig and Wilfley table (WT) treatments on the 0.5-3 mm and 53-500 μm soil size fractions (SF), respectively, and chemical leaching on the <53 μm SF and TL-2, consisting of jig on the 1-4 mm SF, spiral, and WT treatments on 250 μm-1 mm SF, and Kelsey jig assays on the <250 μm SF. For both TL, the untreated SF (>3 mm for TL-1; >4 mm for TL-2), and the gravimetric separation concentrates could be sent for recycling in smelter facilities. Results showed that the finer SF (<53 μm SF for TL-1; <250 μm SF for TL-2) were very difficult to treat. Even with metal removed mass proportions up to 78% for Pb, concentrations were still very high after chemical leaching; and the Kelsey jig showed deceiving metal removed mass proportions (up to 47% for Pb). In both TL, the jig and the WT showed Pb removed mass proportions up to 98% and treated mass proportions up to 77% in their respective SF. Whole process efficiencies in the cleaned soils showed that TL-1 led to the remediation of up to 65% of the initial total soil, and TL-2, 36%. TL-1 and TL-2 results showed that the WT effectively treated soils of 53 μm-1 mm SF, and the jig, soils of the 1-4 mm SF. Our study shows that gravimetric concentration techniques are very promising for the treatment of SAFR backstop soils, and further research has to be done in order to treat the SF lower than 53 μm.
Показать больше [+] Меньше [-]Does a Synoptic Classification Indicate the NOx Pollution Potential? The Case of the Metropolitan Area of Tel Aviv, Israel
2010
Saaroni, Hadas | Ziv, Baruch | Uman, Tatiana
This study examines the synoptic conditions controlling NOx pollution in the metropolitan area of Tel Aviv, using a semi-objective synoptic classification for the eastern Mediterranean. A day in which NOx concentration exceeded the Israeli standard in ≥1 of the seven monitoring stations was defined an “exceeding day” and in ≥5 as an “extensive exceeding day”. For 1998–2004, 19% and 3% of the days were found exceeding and extensive exceeding days, respectively, over 85% of them in the winter months, November–March. The inter-annual variation in the occurrence of the synoptic types was found to explain 72% of the variations in the number of exceeding days. A significant negative trend in the occurrence of types with high pollution potential explained the decrease of 10% per year in the number of exceeding days during 1998–2004. The Red Sea Trough, though being cyclonic system, contributed 51% of the exceeding days, while highs, though being more frequent, contributed only 35%. The “pollution potential” of a synoptic type was defined as the percentage of exceeding days belonging to this type. The majority of synoptic types with the highest pollution potential were cyclonic, most being the Red Sea Trough with western axis, with 82% potential. Our findings indicate that the identity of the synoptic system as cyclonic or anticyclonic is not the key factor for the pollution potential in the study region, but rather, the ambient atmospheric conditions they induce, i.e., high temperatures, static stability, and weak easterly offshore flow. Local processes are the direct cause of the pollution and that the role of the synoptic conditions is to enable, or even to reinforce, the supportive meso-scale processes. This study is a first step in downscaling synoptic features to local NOx pollution potential, constituting a basis for alarming against pollution events, based on the predicted synoptic conditions.
Показать больше [+] Меньше [-]Representation of Particulate Matter COD in Rainfall Runoff from Paved Urban Watersheds
2010
Kim, Jong-Yeop | Sansalone, John J.
For a half century, total suspended solids (TSS) has been the most commonly utilized particulate matter (PM) gravimetric index for wastewater. While TSS has been extended to urban runoff, runoff phenomena are unique. Runoff is unsteady and transports heterodisperse inorganic granulometry, giving rise to the PM index, suspended sediment concentration (SSC). With respect to PM-associated chemical oxygen demand (CODp) in runoff, it is hypothesized that, while the TSS method can represent effluent CODp, the SSC method is required to represent influent CODp. CODp and PM indices (TSS and SSC) for runoff events with mass balances and manual sampling are analyzed to investigate this hypothesis. This study examined a series of rainfall-runoff events captured from an instrumented fully paved urban catchment subject to traffic loadings in Baton Rouge, LA. Results indicate TSS generated substantial event-based mass balance errors for CODp and Δm p (mg/g) across a hydrodynamic separator (HS) as compared to SSC. TSS underestimates sediment-bound COD (>75 µm), a significant portion (maximum of 63% and median of 50%) of influent load. Negative bias by the TSS method for influent CODp load increases as the heterodisperse particle size distribution becomes coarser. Above a PM of 250 mg/L, underestimation of CODp by the TSS method is statistically significant. Utilizing the SSC method, CODp reduction by a HS upstream of a batch clarifier (BC) indicates that a HS does not provide CODp reduction, compared to a BC with 60 min of residence time. Representative PM and CODP assessment suggests frequent BMP and drainage system maintenance to ensure proper operation and reduce pollutant elution.
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