Distribution of minor metallic elements within waste incineration bottom ashes defined by WDX/EDX spectrometry

A number of metallic elements are inherited from waste during thermal treatment and concentrated in the incineration residues. Because the major part of the incineration residue mass are bottom ashes (BAs), their study is of great importance from the point of view of their environmental impact or resource potential. The general focus of this study was on the minor metallic elements present in BAs. They co-occurred with main phases and often determined the inherited potential of the material. The analysed residues were produced from municipal and industrial waste. The BAs were studied using spectroscopic methods of chemical microanalysis: energy dispersive X-ray spectrometry (EDX) and wavelength dispersive X-ray spectrometry (WDX). Both the main and minor metallic elements were concentrated in metallic components. They were typically present as separate grains and metallic inclusions (commonly in the glass matrix of the grains) ranging in size from several to hundreds of micrometres. Despite Fe-, Al- and Cu-rich occurrences, metallic elements rarely occurred in fragments composed of a single element. Their main forms of occurrence were alloy grains, admixtures in polymetallic occurrences and micro-inclusions in glassy matrix. The content of particular elements in those forms was investigated and described in greater detail. Even though two types of bottom ash were formed from different types of waste and differences in used technologies were present, the obtained materials contained metallic components having similar attributes. Elevated concentrations of not only Fe and Al, but also Ti, Cu and Zn, allow us to consider bottom ash as a promising material from the point of view of metallic elements' recovery (e.g. by the physical concentration of elements through gravity or magnetic methods)

The assessment of phosphorus recovery potential in sewage sludge incineration ashes : a case study

A sewage sludge incineration ash contains large amounts of phosphorus, which are considered as a novel anthropogenic waste–based substitute for phosphorus natural resources. Phosphorus is accumulated at most in phosphate minerals of whitlockite structure, that contain Fe, Ca, and Mg and in the matrix composed of Si, Al, Fe, Ca, P, Mg, K, Na in various proportions. The goal of this study was to estimate phosphorus recovery potential. A four-stage sequential extraction, following the modified Golterman procedure, was applied. Separation of four independent fractions enabled to understand better the manner of phosphorus occurrence in the studied ash. The results of the extraction indicated the greatest release of phosphorus combined with organic matter using sulfuric acid. The release was on average at the level of 64%. The chelating Na-EDTA compound indicated lower ability to extract phosphorus (at the level of 35%), and the highest ability to extract heavy metals and potentially toxic elements (As, Zn, Mo). The sequential extraction led to the total recovery of phosphorus of around 40–60

Adjustable Aggressive Pre-Buffer Amount Based On User Location

A system and method for aggressively pre-buffering media content on a device is disclosed. The system includes a mobile computing device installed with an application (app) for accessing a digital distribution platform through a network connection. The app is in communication with a server including a user database. The method includes providing instructions for choosing when to aggressively pre-buffer media content by classifying the likelihood the user will change to a lower quality connection. This likelihood is determined based on the past median connection duration of other users on the same connection. The disclosed system and method reduce the total bandwidth cost required to ensure most users have an appropriate amount of content pre-buffered on their local device. Further, it reduces battery consumption by only aggressively streaming the content when the user is likely to change to a lower quality connection

Iron metallurgy slags as a potential source of critical elements : Nb, Ta and REE

The recovery of valuable metals from metallurgical slag disposals is a promising option to protect natural resources, limited due to technology development and increased consumption. The Ad-hoc Working Group on Defining Critical Raw Materials within the Raw Materials Supply Group has proposed a list of critical elements which have the greatest economic importance and meet the requirements of sustainable development in Europe. The goal of this study was to examine steelmaking- and blast-furnace slags from metallurgical processes to determine concentrations of elements of the greatest criticality for Poland, e.g. Nb, Ta and REE, and to discuss the viability of their recovery. Slag analyses indicate enrichment of REE relative to UCC, NASC and average chondrite compositions in blast-furnace slags and Nb and Ta in steelmaking slags. To make recovery of these critical elements reasonable and profitable, it is recommended that they be recovered together with other useful raw materials

Automatically Adapting Content To Audio-Only Versions

A device and method are disclosed for automatically adapting content to audio-only versions for video playback in situations with bad network connectivity. The method includes replacing a video stream with a non-video version of content stream on detection of poor internet connection. The non-video version of the stream is a different asset in comparison with audio of the video stream, for example, the non-video version might be shorter as they don’t have leading or trailing periods of silence that might be required for on screen transitions, scenes, credits, etc. Further, the method may also include recommending audio-only version of the content to the user instead of mixed media content. When the device recognizes that it is in a poor connectivity state, it can adjust the recommendations, the endpoints, or both

Bee Pollinators and Economic Importance of Pollination in Crop Production : Case of Kakamega, Western Kenya

Bees are the main animal pollinators of crops worldwide. In Kakamega, Western Kenya, farmers do not manage them for pollination but rely on feral pollinators from the nearby habitats. The ability of these habitats to continuously support bees depends on how they are managed by the adjacent communities. Therefore, the overall aim of this study was to elucidate strategies that can be used to improve bee pollination in the Kakamega farmland. The following objectives were defined: i) determine whether the presence of Kakamega forest affects bee pollinator diversity and foraging activity density in crops in the farmland, ii) establish the contribution of bee pollination to crop productivity, iii) assess the knowledge of farmers about bees and pollination, and iv) quantify the economic benefit that farmers derive from pollination of their crops by bees. The data were collected: i) through observation of bees along a transect from fields near the forest to fields 8 km away, ii) in experimental plots with crops with and without bee-pollination, iii) through questionnaire administration to 352 farmers, and iv) through secondary data, mainly sourced from the Ministry of Agriculture. The number of bee species recorded in the fields near and far from the forest was not statistically different, implying that bee diversity in the farmland does not necessarily depend on the forest. However, the activity density of some bee populations (e.g., Xylocopa calens) was significantly higher in fields near the forest, indicating that the forest might be an important element in providing sufficient pollination services in the system, while the presence of a sufficient number of bees for pollination will depend on how the farmland landscape is managed. The increase in crop yield due to bee pollination, tested on nine crops (beans, cowpeas, green grams, bambara nuts, tomatoes, capsicum, passion fruit, sunflower and squash) ranged from 25% (tomatoes) to more than 99% (squash). Thus, although some crops can produce without bee pollination, presence of bees is important to increase yields, and hence, food security and income. Similarly, bee pollination is essential for reproduction in other crops. There was a significant increase in the quality of seeds (e.g., 21%; sunflower oil) and fruit sizes (e.g., capsicum by 29%, leading to a higher market price). The contribution of bee pollination to the farmers’ income in Kakamega in 2005 was about 50% of the annual value of the selected crops (except squash). This was an almost 40% net benefit, suggesting that bee pollination economically benefits crop producers. More than 98% of the farmers knew different bee species but only about 50% knew of the function of bee pollination in crop production. However, after informing them of the role of pollination, more than 98% were willing to pay an estimated US$90 per household annually for pollination of their crops by bees. Both the knowledge of pollination and willingness to pay amount correlated significantly with the education of the farmers. This suggests that education of farmers on issues of bees and pollination can have an impact on bee conservation in the Kakamega farmland. Therefore, farmers and other stakeholders should be trained on the role of bee pollination and its contribution to their welfare and on the use of cost-effective strategies for bee conservation, taking into consideration the locally available resources. For example, landscape management strategies are possible, e.g., proper utilization of hedgerows, which are unique in the farmland and connects it with the forest. Other methods such as use of trap nests for cavity nesting bees and integrated farm management systems, e.g., pest management, should also be considered. Research should be done to provide guidance on how best these strategies can be adopted for bee conservation in the region.Bienenbestäuber und die wirtschaftliche Bedeutung der Bestäubung in der landwirtschaftlichen Produktion - Beispiel Kakamega, West-Kenia Bienen sind die wichtigsten tierischen Best äuber von Nutzpflanzen weltweit. In Kakamega, West-Kenia, betreiben die Bauern keine Bienenhaltung, sondern verlassen sich ausschließlich auf wilde Bestäuber aus den nahe liegenden Habitaten. Die Fähigkeit dieser Habitate, dauerhaft als Lebensraum für die Bienen zu dienen, hängt davon ab, wie diese durch die angrenzenden lokalen Dorfgemeinschaften bewirtschaftet werden. Das Gesamtziel dieser Studie war daher, Strategien zur Verbesserung der Bienenbestäubung im Farmland in Kakamega herauszuarbeiten. Die Ziele im einzelnen waren: i) herauszufinden, ob die Existenz des Kakamega-Waldes die Diversität der Bienenbestäuber sowie die Aktivitätsdichte der futtersuchenden Bienen in den Nutzpflanzen beeinflusst, ii) den Beitrag der Bienenbestäubung zur Produktivität der Nutzpflanzen zu bestimmen, iii) die Kenntnisse der Bauer über Bienen und Bestäubung zu ermitteln, und iv) den wirtschaftlichen Nutzen für die Bauern durch die Bestäubung ihrer Nutzpflanzen durch die Bienen zu quantifizieren. Die Daten wurden erhoben durch: i) Beobachtung der Bienen entlang eines Transekts von Feldern nahe dem Wald bis zu Feldern in 8 km Entfernung, ii) in Versuchsflächen mit Nutzpflanzen mit und ohne Bienenbestäubung, iii) durch Befragungen (Fragebogen) von 352 Bauern, und iv) durch Sekundärdaten, hauptsächlich vom Landwirtschaftsministerium. Die Anzahl der Bienenarten in den Feldern in der Nähe und weiter entfernt vom Wald unterschied sich nicht signifikant. Dies deutet darauf hin, dass die Bienendiversität in den Feldern nicht notwendigerweise von der Nähe des Waldes abhängt. Jedoch war die Aktivitätsdichte einiger Bienenvölker (z.B. Xylocopa calens) signifikant höher in Feldern nahe am Wald, was darauf hindeutet, dass der Wald ein wichtiges Element in der Bereitstellung von Bestäubungsdiensten durch diese Bienenarten darstellen könnte. Der Mehrertrag der Pflanzen durch Bienenbestäubung wurde an neun Anbaupflanzen (Bohne, Kuhbohne, Kichererbse, Bambaranuss, Tomate, Paprika, Passionsfrucht, Sonnenblume und Kürbis) gemessen und lag zwischen 25$ 90 jährlich pro Haushalt zu bezahlen. Sowohl die Kenntnisse über die Bestäubung als auch die Höhe der Summe, die sie bereit waren zu bezahlen, korrelierte signifikant mit der Bildung der Bauern. Dies deutet darauf hin, dass eine entsprechende Ausbildung zum Schutz der Bienen im Farmland in Kakamega beitragen würde. Daher sollten die Bauern und andere Beteiligte eine Ausbildung hinsichtlich der Rolle der Bienenbestäubung und deren Beitrag zu ihrem Wohlergehen sowie über kosteneffektive Bienenschutzstrategien erhalten, wobei die lokalen Gegebenheiten berücksichtigt werden sollten. Strategien zur Bewirtschaftung der Landschaft wären u.a. möglich durch die richtige Nutzung der dort einzigartigen Hecken, die die Felder mit dem Wald verbinden. Andere Maßnahmen wie die Nutzung von Fallennestern für höhlennistende Bienen und integrierte Farmbewirtschaftung, z.B. in der Schädlingsbekämpfung, sollten ebenfalls in Erwägung gezogen werden. Weitere Forschung sollte aufzeigen, wie diese Strategien für den Bienenschutz in dieser Region umgesetzt werden können

The leaching potential of sewage sludge and municipal waste incineration ashes in terms of landfill safety and potential reuse

Incinerations residues from different types of materials (sewage sludge incineration ash and municipal waste incineration ashes) can either be by-products used in industry, or can pose a serious environmental problem related to their composition and the presence of potentially hazardous elements. State regulations and standards indicate whether material is inert, non-hazardous or hazardous. These standards, however, do not provide a complete overview on the leaching behavior of potentially hazardous elements in the environment. This study presents the result of batch experiment performed in accordance with the PN-EN 12457-2 (2006) and PN-EN 12457-4 (2006) standards. The results indicated that the leachability of elements is strongly dependent on the mineral composition of the waste product (the concentration and composition of soluble phase), the chemical composition (the mobility of hazardous elements and their affinity to soluble minerals), and the pH. To ensure environmental safety a thorough characterization of the waste is required followed by qualitative assignment to a particular waste type based on available guidance. Furthermore, to avoid leaching of potentially harmful elements into soils or surface water, it is also paramount to perform environmental impact assessment of wastes used as by-product in industry e.g., as building or road construction materials (aggregate) and fertilizers

Metallic elements occurrences in the municipal waste incineration bottom ash

Bottom ash (BA) samples from a municipal waste incinerator in Poland were collected to investigate metallic components. Numerous metal-rich phases were present in the BA as a part of the incombustible waste fraction, concentrated and modified during thermal treatment. Metallic components in the BA occurred as heterogeneous assemblages of elements with various oxygen content. Fe- and Al-rich occurrences prevailed other types of compositions (e.g. Cu-, Zn- and Ti-rich). Elements in metal-rich phases co-occurred with each other (e.g. Fe occurred with Si, Ca, P, Al and Ti; Al occurred with Fe, Si and Ca; Zn occurred with Ca, Al and Si)

Mineral carbonation of metallurgical slags

Due to increasing emissions of greenhouse gases into the atmosphere number of methods are being proposed to mitigate the risk of climate change. One of them is mineral carbonation. Blast furnace and steel making slags are co-products of metallurgical processes composed of minerals which represent appropriate source of cations required for mineral carbonation. Experimental studies were performed to determine the potential use of slags in this process. Obtained results indicate that steel making slag can be a useful material in CO_2 capture procedures. Slag components dissolved in water are bonded as stable carbonates in the reaction with CO_2 from ambient air. In case of blast furnace slag, the reaction is very slow and minerals are resistant to chemical changes. More time is needed for minerals dissolution and release of cations essential for carbonate crystallisation and thus makes blast furnace slags less favourable in comparison with steel making slag