Volume 20 - 2018

Sustainable recovery of critical metals (CM) from Waste Electrical and Electronic Equipment (WEEE) in the European Union (EU) requires information for detailed analysis, monitoring and decision-making. Related knowledge is currently insufficient or disseminated through the network of stakeholders. This paper assesses the requirements of an adequate Database Management System (DBMS) with participation of different actors involved in the recovery of critical metals and analyses the difficulties and the possibilities found for its implementation. The authors define a conceptual scheme of a DBMS to assess the information requirements and to establish the interactions between different actors of the WEEE supply chain, with the aim of supplying standardized information for management and research. Barriers are studied through a survey to identify obstacles for its elaboration. Limitations for its development are addressed and practical solutions for its elaboration are presented.

The present study aims to investigate the human thermal stress with respect to the synoptic scale circulation over the metropolitan city of Athens in Greece. The Universal Thermal Climate Index (UTCI) was applied in order to assess the levels of thermal stress employing three-hour meteorological data for four stations of the urban complex for a ten-year period (2006-2015). The patterns of the synoptic atmospheric circulation were classified in eight distinct categories based on a clustering scheme. The obtained results in summer reveal low UTCI values on days that are associated with a cyclonic pattern or a cold advection from the northwest or north. On the contrary, the days with an anticyclonic pattern show high UTCI values. During winter, low UTCI values are observed on days that are associated with a pure cyclonic pattern, a prevailing northern flow and a strong cold air advection from the northwest or north. During nighttime, high UTCI values are noted on days with south-westerly flow. However, this is not observed during daytime and especially around midday. The analysis also shows that the position of the station affects the levels of thermal stress for the same synoptic category.

Changji is an arid city in the north west of China which suffers from severe air pollution due to increasing vehicle use and heating with coal. Samples (TSP, PM10, PM5, PM2.5) were collected before and after several snow events, for revealing the snow scavenging effect and influencing mechanisms. The result indicated that the snow scavenging effect was obvious. The highest snow scavenging quantity and scavenging ratio is TSP, followed by PM10, PM5 and PM2.5. Snow scavenging quantity was dependent on the particulate diameter. Snow intensity, drying time and amount of snow influenced scavenging ratio, and snow intensity is the key influencing factor. Scavenging ratio increases with the increase of snow intensity. Higher snow intensity can reduce the selective scavenging of particulate diameters, the scavenging ratio of different particulate diameter will get close to each other. The lower snow intensity was, the higher selectivity was. Light snow will scavenge large particles obviously, but little for small particle.

In this study, the potential use of Azolla filiculoides Lam. for the bioremediative solution to polycyclic aromatic hydrocarbon (PAH) pollution due to crude oil spills in freshwater was investigated. The plants were grown in nitrogen-free Hoagland nutrient solution media containing 0.05%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5% crude oil by volume for 15 days under greenhouse conditions. Relative growth rates of A. filiculoides decreased in the presence of crude oil in a concentration-dependent manner. The probable influence of A. filiculoides on the biodegradation of polycyclic aromatic hydrocarbons was measured by using synchronous UV fluorescence spectroscopy. GC-MS analysis were also carried out to elucidate the behavior of the oil in experimental and control samples. Although 1-2 rings PAHs have not been encountered in control or plant samples, the measured intensity for 3-4 ring PAHs in plant samples was remarkably lower in comparison to the control. Furthermore, these results demonstrated that the predominant efficacy of the A. filiculoides was for 3-4 ring PAHs at the range 0.05 to 0.2% crude oil concentrations. It could be concluded that the bioremediative potential of A. filiculoides for the removal of polycyclic aromatic hydrocarbons strongly depends on the amount of oil in the contaminated water resource. In other words, A. filiculoides could be used more effectively after the removal of excess crude oil in the spilled freshwater areas.