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61.
62.
This paper describes and examines the schemes established in five EU countries for the recycling of packaging waste. The changes in packaging waste management were mainly implemented since the Directive 94/62/EC on packaging and packaging waste entered into force. The analysis of the five systems allowed the authors to identify very different approaches to cope with the same problem: meet the recovery and recycling targets imposed by EU law. Packaging waste is a responsibility of the industry. However, local governments are generally in charge of waste management, particularly in countries with Green Dot schemes or similar extended producer responsibility systems. This leads to the need of establishing a system of financial transfers between the industry and the local governments (particularly regarding the extra costs involved with selective collection and sorting). Using the same methodological approach, the authors also compare the costs and benefits of recycling from the perspective of local public authorities for France, Portugal and Romania. Since the purpose of the current paper is to take note of who is paying for the incremental costs of recycling and whether the industry (i.e. the consumer) is paying for the net financial costs of packaging waste management, environmental impacts are not included in the analysis. The work carried out in this paper highlights some aspects that are prone to be improved and raises several questions that will require further research. In the three countries analyzed more closely in this paper the industry is not paying the net financial cost of packaging waste management. In fact, if the savings attained by diverting packaging waste from other treatment (e.g. landfilling) and the public subsidies to the investment on the “recycling system” are not considered, it seems that the industry should increase the financial support to local authorities (by 125% in France, 50% in Portugal and 170% in Romania). However, in France and Portugal the industry is paying local authorities more than just the incremental costs of recycling (full costs of selective collection and sorting minus the avoided costs). To provide a more definitive judgment on the fairness of the systems it will be necessary to assess the cost efficiency of waste management operators (and judge whether operators are claiming costs or eliciting “prices”).  相似文献   
63.
The control and inhibition of pyrite bioleaching involved in the generation of acid mine drainage was studied. Inhibition of pyrite bioleaching was performed by varying the pyrite concentration in the medium (substrate inhibition) and/or by addition of limestone (inhibition by pH increase) and olive pomace (inhibition by organic compounds). Inhibition tests of pyrite bioleaching were performed according to a full factorial design with three factors (pyrite, limestone and olive pomace) taken at two levels. Preliminary pyrite bioleaching tests showed the ability of the available inoculum to oxidise the mineral. Subsequently, experimental data for total soluble iron denoted strong inhibition under all the different operating conditions of the factorial design, except when larger pyrite concentrations were used. In particular, inhibition by limestone was due to the increase in pH which negatively affects microorganisms, while inhibition by olive pomace may be related to the antioxidant properties of polyphenols. Interactions among operating conditions were specifically assessed by analysis of variance. Only limestone and/or pomace addition resulted in a significant (95%) diminution of iron extraction.  相似文献   
64.
Escalation theory proposes enemy-related selection as the most relevant factor of natural selection among individual organisms. When hazardous to predators, prey might be considered enemies that influence predator evolution. Opisthobranch molluscs that prey on chemically defended prey are an interesting study case on this subject. Predation on chemically defended species paved the way for opisthobranchs to enter in an arms race, developing means to detoxify and/or excrete harmful compounds, which led to the sequestration of those compounds and their self-defensive use, an escalation of defenses. Here we aim to understand whether the opisthobranch predator is better protected than its chemically defended prey, using as predator–prey model, a nudibranch (Hypselodoris cantabrica) and the sponge it preys upon (Dysidea fragilis), and from which it obtains deterrent chemical compounds. Specimens of both species were collected on the Portuguese coast, and their crude extracts were analyzed and used in palatability tests. Nudibranchs revealed a higher natural concentration of crude extract, probably due to a progressive accumulation of the compounds. Both predator and prey extracts revealed similar mixtures of deterrent metabolites (furanosesquiterpenes). Palatability tests revealed a more effective deterrence in the nudibranch extracts because significant rejection rates were observed at lower concentrations than those necessary for the sponge extracts to have the same effect. We concluded that the predator is chemically better protected than its prey, which suggests that its acquisition of chemical defenses reveals a defensive escalation.  相似文献   
65.
The reproductive cycles and abundance of the sympatric colonial ascidians Pycnoclavella brava, Pycnoclavella aurilucens and Pycnoclavella communis from two Northwestern Mediterranean sites over a period of 2.5 years are reported. The species showed some differences in their biological patterns. Gonad maturation and larval brooding took place during autumn and early winter for P. communis, during spring for P. aurilucens and during late winter and spring for P. brava. Summer was found to be the unfavorable season for all species, and an aestivation period occurred in P. communis and P. brava. Maximum abundance for the three species was observed during winter. Growth rates of the most abundant species, P. communis, were also monitored and found to peak during the initial phases of reactivation after aestivation. Growth rates decreased afterwards, becoming negative as water temperature started to increase after the winter minima. Reproductive activity and growth rates for P. communis displayed a temporal lag that suggested partitioning of resources to either reproduction or growth in this species.  相似文献   
66.
The coastline of the state of Rio Grande do Sul (Brazil) is used annually as a migratory route by a number of seabird species. Thirteen surveys were carried out between July 1997 and July 1998 to obtain information on the diet of Puffinus gravis, Puffinus griseus, and Puffinus puffinus along the coast of Rio Grande do Sul. Sampling efforts focused on dead beach-cast specimens. One hundred twenty-one stomach content analyses were performed on P. gravis from a total of 238 specimens; 17 stomach content analyses were performed on P. griseus from a total of 54 specimens; and 25 stomach content analyses were performed on 25 P. puffinus from a total of 61 dead specimens. Cephalopods were the main prey found in the stomachs of the three species and were present in 96% of the P. gravis stomachs. The following cephalopods were observed: Ommastrephidae, Gonatus antarcticus, Gonatus sp., Lycoteuthis lorigera, Lycoteuthis sp., Histioteuthis sp., Cycloteuthis sp., Loligo plei, Loligo sanpaulensis, Sepiidae, and Argonauta nodosa. The latter was the most abundant species in the three species of Puffinus. The following fish were identified from otoliths: Porichthys porosissimus, Ctenosciaena gracilicirrhus, Paralonchurus brasiliensis, Cynoscion guatucupa, and Trichiurus lepturus. There was also a high incidence of synthetic materials such as plastic, polyethylene and rubber.  相似文献   
67.
The relationship between specific particulate emission control and ambient levels of some PM10 components (Zn, As, Pb, Cs, Tl) was evaluated. To this end, the industrial area of Castellón (Eastern Spain) was selected, where around 40% of the EU glazed ceramic tiles and a high proportion of EU ceramic frits are produced. The PM10 emissions from the ceramic processes were calculated over the period 2000–2006, taking into account the degree of implementation of corrective measures throughout the study period. Abatement systems were implemented in the majority of the fusion kilns for frit manufacture in the area as a result of the application of the Directive 1996/61/EC, leading to a marked decrease in PM10 emissions. By contrast, emissions from tile manufacture remained relatively constant because of the few changes in the implementation of corrective measures. On the other hand, ambient PM10 levels and composition measurements were carried out from 2002 to 2006. A high correlation between PM10 emissions from frit manufacture and ambient levels of Zn, As, Pb and Cs (R2 from 0.61 to 0.98) was observed. On the basis of these results, the potential impact of the implementation of corrective measures to reduce emissions from tile manufacture was quantified, resulting in a possible decrease of 3–5 μg/m3 and 2 μg/m3 in ambient mineral PM10 (on an annual basis) in urban and suburban areas, respectively. This relatively simple methodology allows us to estimate the direct effect of a reduction in primary particulate emissions on ambient levels of key particulate components, and to make a preliminary quantification of the possibilities of air quality improvement by means of further emission reduction. Therefore, it is a useful tool for developing future air quality plans in the study area and in other industrialised areas.  相似文献   
68.
Green sand reclamation using a fluidized bed with an attrition nozzle   总被引:1,自引:0,他引:1  
The objective of this study was to determine the technical feasibility of green sand reclamation using attrition in a gas–solid fluidized bed. Reclamation of foundry sand is becoming important as it may help solve concerns related to transportation and dumping of the used sand, and reduce production costs by recycling sand. The crucial step in green sand reclamation is the removal of small clay particles that are bound to the sand particles.For this study two different types of green sand were used and supplied by two different foundries. Tests were performed in a fluidized bed equipped with an attrition nozzle operating at pressures of either 350 or 550 kPa (50 or 80 psig). Attrition experiments for one green sand were performed on either unburned or burned (calcined) green sand, to determine the effect of prior calcination of the green sand on its reclamation potential by attrition. Calcination temperatures of over 700 °C were employed, and the results suggest that calcination facilitates the removal of clay from the green sand.Green sand was analyzed for clay and organic content, acid request, and particle size before and after attrition. Attriting calcined green sand produces the best results. Also experiments conducted at the highest attrition pressure of 550 kPa gave good results. According to the mass balance, the mass lost during the attrition process may be limited to less than 14%, and this could be considered acceptable. The volume of air required for the attrition nozzle is rather high and this may adversely affect the economics of the process.  相似文献   
69.
Natural hazards were the cause of approximately 16,600 hazardous material (hazmat) releases reported to the National Response Center (NRC) between 1990 and 2008-three per cent of all reported hazmat releases. Rain-induced releases were most numerous (26 per cent of the total), followed by those associated with hurricanes (20 per cent), many of which resulted from major episodes in 2005 and 2008. Winds, storms or other weather-related phenomena were responsible for another 25 per cent of hazmat releases. Large releases were most frequently due to major natural disasters. For instance, hurricane-induced releases of petroleum from storage tanks account for a large fraction of the total volume of petroleum released during 'natechs' (understood here as a natural hazard and the hazardous materials release that results). Among the most commonly released chemicals were nitrogen oxides, benzene, and polychlorinated biphenyls. Three deaths, 52 injuries, and the evacuation of at least 5,000 persons were recorded as a consequence of natech events. Overall, results suggest that the number of natechs increased over the study period (1990-2008) with potential for serious human and environmental impacts.  相似文献   
70.
Solids and nutrient removal from flushed swine manure using polyacrylamides   总被引:1,自引:0,他引:1  
Most of the organic nutrient elements (nitrogen and phosphorus) and carbon compounds in liquid swine are contained in fine suspended particles. Flocculation treatment with polyacrylamide (PAM) followed by screening is one the best methods to separate the liquid fraction from the solid fraction in swine manure, and thus to eliminate nutrient elements associated with solids. In this study, the efficiency of a synthetic polyacrylamide to treat swine manure was evaluated. After polymer treatment samples were sieved and the filtrated liquid was analyzed. TSS, VSS and COD concentrations in the liquid fraction were 2.17, 1.93 and 16.42 g/L respectively, accounting for 94, 94 and 77% removal percentages for TSS, VSS and COD using 30 mg/L of PAM.  相似文献   
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