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)

Hip arthroplasty : infections, thromboembolic events and surgical environment

Background Each year hip arthroplasties increase the quality of life for over 1 million patients worldwide. Although the complication rates are low, the absolute numbers are rising as the numbers of procedures increase. Prosthetic joint infections resulting from intraoperative contamination are regarded as compensable by the Swedish patient insurance. Healthcare personnel are obliged to inform patients about their injury and the possibility to claim it. In this thesis aspects of two complications after hip arthroplasty are discussed. Both have gone from being relatively frequent complications of uncommon procedures in the early days of hip arthroplasty, to infrequent complications of common procedures, resulting in many suffering patients. Prosthetic joint infection (Study I – III) is the most feared complication and venous thromboembolism is the most common medical complication, (Study IV). Methods Studies I and II are based on outcomes of operations performed at the Department of Orthopaedics, Stockholm South General Hospital (Södersjukhuset). Studies III and IV cover the nationwide population of Sweden and are based on data from national quality and healthcare registers. Study I: 3 884 patients operated between 1996 and 2005, due to degenerative hip disorder or hip fracture (primary and secondary fracture prostheses) were analysed for the incidence, microbiology and outcome of prosthetic joint infection after hip arthroplasty. Study II: Air quality in the operating room was evaluated through comparison of three clothing systems through 244 measurements of colony forming units per square meter, during 37 operations. Study III: A national cohort of prosthetic infections after total hip arthroplasties in patients operated between 2005 and 2008 has previously established. We analysed the number of filed patient claims in 441 infections and examined the incidence and outcome (accepted, rejected, approved disability). Study IV: Low molecular weight heparins and new oral anticoagulants were compared as thromboprophylaxis after 32 663 elective hip arthroplasties, through determination of effectiveness as incidence of venous thromboembolic events and assessment of safety by analysis of bleedings, reoperations and mortality. Results Study I: The infection rates for degenerative hip disorder and primary and secondary fracture prostheses were 0.4%, 2.1% and 2.5% respectively. The patient factors associated with a significantly increased risk for developing a surgical-site infection were both fracture indication for surgery and male gender. Staphylococcus Aureus and Coagulase-Negative Staphylococci dominated as microbiological agents. Treatment of 27 (44%) patients resulted in permanent resection arthroplasty, of which 22 (81%) were fracture patients. Study II: Compared with the two other reusable suits, the significantly lowest values of colony forming units were observed with the single-use polypropylene BARRIER® Clean Air Suit. Study III: 329 (75%) of patients did not file a claim of injury to LÖF and of those 112 that did, 108 (96%) were accepted as eligible for compensation. Patients’ age above 72 years and fracture diagnosis were the only significant factors associated with not filing a claim of injury. Study IV: Compared to low molecular weight heparins, new oral anticoagulants reduced the risk of venous thromboembolic events with more than 50% with simultaneously remained safety profile. In the subset of patients treated with low molecular weight heparins no significant difference with regards to the studied outcomes was observed. Conclusion Patients with fractures of the neck of femur, treated with primary or secondary fracture prostheses, have a greater risk of infection and display worse outcomes compared with patients operated due to degenerative hip disorders. Additionally, among the overall low rate of patient claims, fracture patients stand out with an even greater share of non-claimants (87%). Healthcare personnel should increase their knowledge about LÖF. Improving air quality is difficult in existing facilities. Evaluation of clothing in real-life surgical environments can, by decreased counts of airborne bacteria, result in better prevention of infections. Compared to low molecular weight heparins, thromboprophylaxis with new oral anticoagulants extending for a minimum of 28 days is a superior regimen for the majority of patients undergoing elective primary total hip arthroplasty

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

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)

Assessment of valuable and critical elements recovery potential in ashes from processes of solid municipal waste and sewage sludge thermal treatment

Due to the increasing amount of produced and accumulated wastes, a potential source of elements might be the global waste stream coming from the waste incineration process. As a result of this process, bottom ash, fly ash and air pollution control residues are produced. The goal of this study was to evaluate the raw material potential of the anthropogenic materials which are fly ashes from municipal waste incineration and municipal sewage sludge incineration, and the possibility for the recovery of metallic or other economically valuable elements by comparison of their chemical composition with the chemical composition of Earth materials (ultramafic, mafic and felsic igneous rocks, various sedimentary rocks), and with their lowest content in currently exploited ores. Fly ashes contain more valuable and critical elements when compared to Earth materials; however, they are less concentrated in comparison to the content in currently exploited ores. Since natural resources are becoming depleted, the costs of exploitation, mineral processing and related operations are increasing and the fly ashes are easily accessible. Cheap materials do not demand complicated treatment which might be considered as a future source of P, Zn, Sn, Cr, Pb, Au and Ag, and thus fulfilling the assumptions of close-loop economy and to maximize natural resources protection

Characterization of incineration residues from wastewater treatment plant in Polish city : a future waste based source of valuable elements?

To support the rational management of raw materials in the European Union more attention is being paid to the resource potential of waste materials, which are increasing in volume due to industrial development and the world population growth. One of the methods to reduce the amount of produced and landfilled waste is incineration. As a result of sewage sludge incineration, fly ash (ISSA-incinerated sewage sludge ash) and APC (air pollution control) residues are produced. The goal of this study was to characterize incineration residues from waste water treatment plant in Polish city with ca. one million inhabitants using mineralogical, chemical methods, and to estimate the recovery potential of valuable components. Both incineration products accumulate elements which are of valuable concentrations, such as P (17 wt% of P_{2}O_{5} on average in the ISSA), as well as significant amounts of metals such as Zn, Pb, Cu, Ni, and Cr. Small particle sizes < 125 \mu m in both materials favor the accumulation of elements of higher volatility during incineration, but they are usually dispersed within a matrix, main minerals or amorphous substance, or are present in the form of micro inclusions or grains < 10 \mu m, which thus excludes their easy recovery

Seasonal changes in chemical and mineralogical composition of sewage sludge incineration residues and their potential for metallic elements and valuable components recovery

The incineration products composition is dependent on the incineration technology, operating conditions and also on the waste feed composition, which can change seasonally, depending on the temporal growth of the population due to tourism, micro-industry seasonality, intensity of atmospheric precipitation and other factors. Seasonal variations in potentially valuable elements concentrations in incineration products are visible but their overall content is low, therefore this material should not be considered as a source of valuable elements. Due to high content of phosphorus (7.5 wt%) only the fly ash can be considered as a potential source of this critical raw material

Metallic elements fractionation in municipal solid waste incineration residues

Municipal solid waste incineration residues from one of the Polish incineration plants were sampled to characterize the distribution of metallic elements among them. Those elements previously dispersed within the waste mass, as a result of incineration processes were unequally distributed to bottom ash (BA), fly ash (FA) and air pollution control residues (APC) due to their physical properties, form of occurrence and characteristics of the incineration system. Fe, Cu, Cr were concentrated in BA; Mg, Ti in FA; Pb, Sn in APC. Beside them several elements were equally distributed among BA and FA (Al, Mn), and FA and APC (Zn)

Metals accumulation during thermal processing of sewage sludge : characterization of fly ash and Air Pollution Control (APC) residues

Sewage sludge thermal utilization leads to production of fly ash and APC residues which may contain elevated amounts of some metallic or toxic elements (Fe, Zn, Pb, Sn, Au, Hg, Cd, As). Distribution of these elements in studied fly ash and APC residues was unequal and dependent on their melting temperature. Metals in fly ash are present as Fe-rich grains and rims around Si-glass whereas in APC metallic components are mostly represented by Sn-rich inclusions dispersed in matrix, Ca-phosphates or as separate micro-grains. Elements concentrations were elevated but overall content was low thus disqualifying the material in terms of recovery