Investigating sources and sinks of N2O expression from freshwater microbial communities in urban watershed sediments

Wastewater treatment plants (WWTPs) serve as point-source inputs for a variety of nutrients often dominated by nitrogenous compounds as a result of anthropogenic influence. These effluents can impact biogeochemical cycles in freshwater estuaries, influencing microbial communities in both the water and sediment compartments. To assess the impact of point source nutrients, a transect of sediment and pore water samples were collected from 4 locations in the Little River Sub-watershed including locations above and below the Little River Pollution Control Plant (LRPCP). Variation in chemistry and microbial community/gene expression revealed significant influences of the effluent discharge on the adjacent sediments. Phosphorus and sulfur showed high concentrations within plume sediments compared to the reference sediments while nitrate concentrations were low. Increased abundance of denitrifiers Dechloromonas, Dok59 and Thermomonas correlating with increased expression of nitrous-oxide reductase suggests a conversion of N2O to N2 within the LRPCP effluent sediments. This study provides valuable insight into the gene regulation of microbes involved in N metabolism (denitrification, nitrification, and nitrite reduction to ammonia) within the sediment compartment influenced by wastewater effluent. © 2017 Elsevier Lt

Biogeochemical Characterization of Metal Behavior from Novel Mussel Shell Bioreactor Sludge Residues

Acid mine drainage (AMD) remediation commonly produces byproducts which must be stored or utilized to reduce the risk of further contamination. A mussel shell bioreactor has been implemented at a coal mine in New Zealand, which is an effective remediation option, although an accumulated sludge layer decreased efficiency which was then removed and requires storage. To understand associated risks related to storage or use of the AMD sludge material, a laboratory mesocosm study investigated the physio-chemical and biological influence in two conditions: anoxic storage (burial deep within a waste rock dump) or exposure to oxic environments (use of sludge on the surface of the mine). Solid phase characterization by Scanning Electron Microscopy (SEM) and selective extraction was completed to compare two environmental conditions (oxic and anoxic) under biologically active and abiotic systems (achieved by gamma irradiation). Changes in microbial community structure were monitored using 16s rDNA amplification and next-generation sequencing. The results indicate that microbes in an oxic environment increase the formation of oxyhydroxides and acidic conditions increase metal mobility. In an oxic and circumneutral environment, the AMD sludge may be repurposed to act as an oxygen barrier for mine tailings or soil amendment. Anoxic conditions would likely promote the biomineralization of sulfide minerals in the AMD sludge by sulfate reducing bacteria (SRB), which were abundant in the system. The anoxic conditions reduced the risk of trace metals (Zn) associated with oxides, but increased Fe associated with organic material. In summary, fewer risks are associated with anoxic burial but repurposing in an oxic condition may be appropriate under favorable conditions

Physicochemical gradients, diffusive flux, and sediment oxygen demand within oil sands tailings materials from Alberta, Canada

The Athabasca Oil Sands contain one of the world\u27s largest oil reserves consisting of approximately 168 billion barrels of currently recoverable bitumen. With 20% recoverable through open pit mining methods, this extraction process produces a considerable amount of fluid fine tailings (FFT) waste material, which must be deposited on site in tailings ponds. These ponds allow the waste sand, clay and residual bitumen to settle out of the water column, allowing for the water to be recycled for use again in the extraction process. It is vital to gain a better understanding of the processes contributing to the development of physicochemical gradients (pH, Eh, Oxygen etc…) that form in these tailings ponds over time, with the goal of remediation and subsequent construction of end-pit lake systems once oil extraction has ceased. To differentiate between the impacts of biotic and abiotic processes in fresh (newly processed material) and mature FFT (∼38 year old tailings) over a 52-week study, a specific experimental design was utilized in accordance with novel microsensor profiling techniques. The sulfide diffusive fluxes within mature biotic systems measured 37.6 μmol m−2 day−1 at the onset of the experiment, decreasing over time, as FeS mineralization progressed. In addition, DO fluxes also showed strong correlation to the physical affects of consolidation, and overall biological consumption of O2 at the FFT-water interface. This holistic study comparing different tailings pond materials provides insight regarding biotransformation and physicochemical controls effecting sediment oxygen demand associated with reclaimed wetlands and end pit lake development

Mikroskopische Visionen für Montage und Greiftechnik

Montage und Handhabungstechnik gewinnen in der Produktion von Mikro-Systemen eine immer größere Bedeutung, wie die am IPA durchgeführten Marktstudie zeigt. Neue Greifsysteme wie der Adhäsionsgreifer ermöglichen ein Vordringen in kleinste Dimmensionen von Bauelementen

Verfahren sowie Vorrichtung zum Zusammenfuehren und Fuegen wenigstens zweier dielektrischer Mikrobauteile

The method uses controlled handling of the microcomponents via electric fields, with relative positioning of the microcompnents separated from one another via a liquid or gel of relatively low electrical conductivity. One of the microcomponents is fixed in position via the electrical field provided by a holding and positioning electrode device (20), a further microcomponent controlled via a dynamic electrical field, for positioning and fixing relative to the first microcomponent. USE - For assembly of hybrid microsystems, e.g. dielectric motors etc., having dimensions of the order of tenths of millimetres

Biogeochemical Characterization of Metal Behavior from Novel Mussel Shell Bioreactor Sludge Residues

Acid mine drainage (AMD) remediation commonly produces byproducts which must be stored or utilized to reduce the risk of further contamination. A mussel shell bioreactor has been implemented at a coal mine in New Zealand, which is an effective remediation option, although an accumulated sludge layer decreased efficiency which was then removed and requires storage. To understand associated risks related to storage or use of the AMD sludge material, a laboratory mesocosm study investigated the physio-chemical and biological influence in two conditions: anoxic storage (burial deep within a waste rock dump) or exposure to oxic environments (use of sludge on the surface of the mine). Solid phase characterization by Scanning Electron Microscopy (SEM) and selective extraction was completed to compare two environmental conditions (oxic and anoxic) under biologically active and abiotic systems (achieved by gamma irradiation). Changes in microbial community structure were monitored using 16s rDNA amplification and next-generation sequencing. The results indicate that microbes in an oxic environment increase the formation of oxyhydroxides and acidic conditions increase metal mobility. In an oxic and circumneutral environment, the AMD sludge may be repurposed to act as an oxygen barrier for mine tailings or soil amendment. Anoxic conditions would likely promote the biomineralization of sulfide minerals in the AMD sludge by sulfate reducing bacteria (SRB), which were abundant in the system. The anoxic conditions reduced the risk of trace metals (Zn) associated with oxides, but increased Fe associated with organic material. In summary, fewer risks are associated with anoxic burial but repurposing in an oxic condition may be appropriate under favorable conditions

Microperfusion pump-systems and development

Transluminal coronary angioplasty has become an established form of treatment for coronary artery disease. The dilatiation time is normally restricted by the ischaemic tolerance. Until today passive perfusion catheters have been used to maintain coronary blood flow to the distal segment. However, such continuous perfusion has often been insufficient to retain myocardial function. Active perfusion catheters, instead, have not been introduced so far for technical reasons. Active coronary perfusion via dilatation catheters with an intracorporal rotary micropump was the objective of investigations by Fraunhofer IPA and the University of Essen. The result of the development activities was an internal geared pump with an outer diameter of 2,5 mm. Several design studies were undertaken to integrate the micropump in a PTCA catheter. The most important aspect of the integrated micropump is that the dilatation time can be prolonged. First in vitro tests with whole-blood showed acceptable mechani cal haemolysis of the pump system. Further in vitro tests will lead to an optimized pump design with low mechanical haemolysis and a high flow rate

Neue Werkzeuge für die minimalinvasive Therapie auf der Basis eines fluidisch angetriebenen, rotatorischen Mikromotors bzw. einer Mikropumpe

Die Entwicklungsarbeiten haben gezeigt, daß mikrohydraulische Komponenten eine interessante und leistungsfähige Erweiterung der heute in der Medizintechnik verfügbaren Aktoren darstellen. Hervorzuheben sind bei Pumpsystemen der hohe Druck sowie der äußerst variable Durchfluß bei einem gleichzeitig sehr einfachen und robusten Aufbau des Gesamtsystems. Hydromotoren erzielen im Verhältnis zu ihrer Größe hohe Drehmomente. Im Größenbereich von 1-20 mm Außendurchmesser bieten diese Systeme ein hochinnovatives Potential für neue Produktentwicklungen. Hervorragende Erfahrungen hinsichtlich der Fertigung der komplexen Teile konnten mit der Erosion erzielt werden, die aufgrund der erzielten Formtoleranz die außerordentlichen Leistungdaten der Mikropumpe möglich macht